We exploit microscale, thin-film gallium arsenide (GaAs) lasers integrated onto silicon (Si) substrates via transfer printing, with a thermally conductive interface material for continuous wave (CW) operation at room temperature. Concepts that bypass existing challenges for III-V/Si integration are presented, and we demonstrate them in strategies for releasing and transfer printing fully formed, functional thin-film microscale GaAs based lasers onto Si substrates where a metallic thin film serves as an adhesive and a thermally conductive interface. Numerical simulations reveal the key considerations in thermal management, with an emphasis on the role of this interface layer. Electrically pumped devices printed on Si exhibit continuous-wave (CW) lasing in the near-infrared range (around 820 nm) at room temperature, with performance comparable to unreleased devices on their native substrates. The spectral shift is consistent with thermal modeling. In addition, preliminary experiments show that the laser devices are possible to be integrated with Si waveguide arrays as well as flexible substrates. The results presented here have promise as generalized routes for advanced heterogeneous integration in next-generation electronic and photonic circuits.

The damages of TEA-CO₂ laser to HgCdTe imaging sensor are researched experimentally and theoretically. The shadows, cracks and dark line are observed. There is a gap between photosensitive layer and CdZnTe which decreases light transmittance, so that the shadows occur. It shows that the crack damages begin from photosensitive layer. The sensor is irradiated by pulse laser, the absorptivity of photosensitive layer is strong, sharp temperatures fluctuations inside the sensor, leading to stress. With the stress increased, the cracks are observed on the surface of the detector. Cracked the surface of the substrate, and effective transmission reduced, which caused gray pixel response decline. The dark line in image occurs several times because Hg atoms separate out from the detector and gather together at the Si-COMS which makes a short circuit between silicon substrate and signal choice line. The volatility of Hg makes the short circuit is unstable, resulting in the dark line repeated in the output image, but the short circuit occurs by chance.

The spatial temporal evolution of the electromagnetic instability and thermal flux reduction in anisotropic plasmas were investigated by using electromagnetic relativistic particle-in-cell simulations. The onset and nonlinear saturation process generating mechanism of the self-generated magnetic fields and physical essence of electron thermal flux reduction were discussed. Numerical simulations show that: In an anisotropic plasma electronic return and internal transport of hot electrons to the target in the process of formation of self-generated magnetic field on the epithermal electron beam heat flux carried by inhibition. These results may be important for understanding of the self-generated magnetic fields generating mechanism, electron thermal flux reduction and electron propagation in fast ignition physics.

Recent years, millisecond laser become a research hotspot. Avalanche photodiode (APD) based on silicon structure has excellent characteristics such as low noise and high-sensitivity. It is key components in receives for long-haul high-bit-rate optical communication system. The failure mechanism of silicon APD remains quite unknown, although some silicon p-i-n photodiode failure modes have been speculated. The COMSOL Multiphysics finite element analysis software was utilized in this paper. And the 2D model, which based on heat conduction equation, was established to simulate the temperature field of the silicon avalanche photodiode irradiated by millisecond laser. The model presented in the following section is a work which considers only melting of silicon by a millisecond laser pulse. The temperature dependences of material properties are taken into account, which has a great influence on the temperature fields indicated by the numerical results. The pulsed laser-induced transient temperature fields in silicon avalanche photodiode are obtained, which will be useful in the research on the mechanism of interactions between millisecond laser and photodiode. The evolution of temperature at the central point of the top surface, the temperature distribution along the radial direction in the end of laser irradiation and the temperature distribution along the axial direction in the end of laser irradiation were considered. Meanwhile, the fluence threshold value was obtained through the model. The conclusions had a reference value for revealing the mechanism of interactions between millisecond laser and the silicon avalanche photodiode.

A high efficiency Tm³⁺-doped fiber seed source system has demonstrated. The pumping laser and output laser in the optical fiber distribution were analyzed. High performance output laser would be obtained by reasonable design of laser parameters, selecting the optimum length of gain fiber, and increasing injection power. Tm³⁺-doping concentration of 7.5×10²⁴ m^-3 and the optimum length of gain fiber of 2 m were used in the experiments. The continuous wave laser with output power of 5.01 W and the beam quality of M²_x = 1.35, M²_y = 1.51 was obtained by fiber coil diameters of 10 cm and injection power of 17.61 W. A slope efficiency and conversion efficiency were up to 36.2% and 28.4%, respectively. The fiber length of 1 m, 1.5 m, 2 m, 2.5 m, 3 m were chosen in the experiments, and the effects of different fiber lengths on the output characteristic were researched. The laser loss was reduced, and the conversion efficiency and beam quality were improved effectively by selecting the length of gain fiber and Tm³⁺-doping concentration reasonably. Theoretical analysis and experimental results show that a higher output power can be achieved by increasing the injection power. It provides a strong experimental foundation for further researching on high power Tm³⁺-doped pulse fiber amplifier by using this Tm³⁺-doped fiber laser as a seed source system.

The affecting factors of 2 μm Tm³⁺-doped fiber laser output characteristics were theoretical analyzed. On the basis of the energy level structure and optical absorption properties of Tm³⁺ ion, combining with the basic principle of Tm³⁺-doped fiber laser, and starting from the energy level structures and the cross relaxation processes of Tm³⁺ ion, the three pumping methods of Tm doped fiber laser (TDF) were analyzed and discussed. The influences of output characteristics by different influence factors were simulated. Based on optimization of the equations, for different fiber lengths, doping concentrations and pumping absorption coefficients and other influence factors, the laser output characteristics under different conditions were obtained and analyzed. Combination the simulation analysis, through the reasonable design and the selection of the optimum parameters of the laser system, the high laser output performance scan be achieved by improving the injection power and controlling of fiber coil diameter. The influences of different factors on the output characteristics were analyzed in the issue. The high laser output performances can be obtained and the laser loss was reduced by selecting the parameters of the laser system properly.

Using millisecond pulse laser irradiating CCD detector, the interacting process between millisecond pulse laser and CCD detector was studied, the forming reason of different damage effects was analyzed, the damage process and damage laws of CCD detector under millisecond pulse laser were revealed. The results show that: with the same laser energy density, the maximum temperature and the damaged area increased with the increase of pulse number; with the same pulse number, the range of the noise widened with the increase of laser energy density, and the vertical shift register impedance values decreased with the increase of laser energy density; the microlens layer on the damaged edge of CCD detector occurred stress damage.

In asymmetrical suspension systems, triaxial signals' phase differences of fiber optic vector hydrophones are nonzero, which is a serious problem for direction of arrival (DOA) estimations of underwater acoustic signals. In this paper, an asymmetrical suspension system is described. Dynamics analysis of the suspension system is performed by using the analytic geometry method. Triaxial resonant frequencies of the suspension system are gotten, phase delays between the outer signals and the hydrophone's triaxial signals are derived, and influence of the suspension system on phase differences in low frequency zone is theoretically explained and simulated. Then frequency responses of the hydrophone in four suspension states are tested in a standing wave tube. The results indicate that both phase differences of xy axes and zy axes are large at resonant frequencies of the suspension system, which is approximately coincided with the theoretical analysis. Phase difference of zy axes at frequency higher than 500 Hz is obvious, which results from resonant responses of the fiber optic vector hydrophone. It proves that symmetry of the suspension system has great influence on phase differences of the fiber optic vector hydrophones.

We have demonstrated a single frequency mid-infrared optical parametric oscillator pumped by a high power continuous wave single frequency fiber amplifier. The pump power was 15W and the corresponding extraction efficiency was 56%, which is close to the theoretical calculated maximum efficiency of 70% under Gaussian beam assumption. In the experiments the volume Bragg grating was 14.9 mm long with the diffractive efficiency of 99.5% at 1550.5 nm. The diffractive spectral linewidth was 0.27 nm. When the working temperature of the PPLN crystal was 51.5°C and the poling period was 30.5μm a stable idler radiation at 3400 nm was generated. To obtain single frequency operation, an uncoated YAG inter-cavity etalon with 5 mm thickness was inserted into the folded cavity. Stable single frequency operation was obtained with the spectral linewidth of 37.5 MHz and the output power of 2.2 W. The central wavelength stability was better than 520 MHz over 1 hour, which was limited by the resolution of the spectrometer. By changing the angle of the YAG etalon the central wavelength of the idler was varied in the range of 0.24 nm.

The 1064nm fundamental wave (FW) and the 532nm second harmonic wave (SHW) of Nd:YAG laser have been widely applied in many fields. In some military applications requiring interference in both visible and near-infrared spectrum range, the de-identification interference technology based on the dual wavelength composite output of FW and SHW offers an effective way of making the device or equipment miniaturized and low cost. In this paper, the application of 1064nm and 532nm dual-wavelength composite output technology in military electro-optical countermeasure is studied. A certain resonator configuration that can achieve composite laser output with high power, high beam quality and high repetition rate is proposed. Considering the thermal lens effect, the stability of this certain resonator is analyzed based on the theory of cavity transfer matrix. It shows that with the increase of thermal effect, the intracavity fundamental mode volume decreased, resulting the peak fluctuation of cavity stability parameter. To explore the impact the resonator parameters does to characteristics and output ratio of composite laser, the solid-state laser’s dual-wavelength composite output models in both continuous and pulsed condition are established by theory of steady state equation and rate equation. Throughout theoretical simulation and analysis, the optimal KTP length and best FW transmissivity are obtained. The experiment is then carried out to verify the correctness of theoretical calculation result.

In this paper, a novel criterion for evaluating the beam quality of high energy laser is proposed, which is called “power outside the large bucket”, P_OLB for short. The novel criterion does not demonstrate the divergence of the beam but focuses on the high spatial frequency wavefront aberration of the beam. The P_OLB values of the laser beams with various aberrations are calculated. It shows that the more high spatial frequency components in the aberration the larger P_OLB value is. Moreover, it is theoretically analyzed that the laser beams with various aberrations are corrected by ideal adaptive optics (AO) systems with different deformation mirror (DM) actuator numbers. It is shown that the residual error of the corrected wavefront aberration with many high spatial frequency components is quite large. Finally, the dependence of the residual wavefront error on the P_OLB value is investigated. Only if the P_OLB is smaller than 3.8/3.4/2.5/1.7 the residual error of the wavefront may be smaller than λ/10, which is corrected by an ideal AO system with 127/61/37/19 actuators. It is necessary to employ a complicated AO system for improving the laser beam of which the P_OLB value is large. The novel evaluating criterion P_OLB is able to demonstrate the amount of high spatial frequency aberration and the residual wavefront error corrected by AO system. It is an accessible and useful criterion for evaluating the beam quality of high energy lasers.

Optical earth imaging simulation of a space target in orbit and it's extraction in laser illumination condition were discussed. Based on the orbit and corresponding attitude of a satellite, its 3D imaging rendering was built. General simulation platform was researched, which was adaptive to variable 3D satellite models and relative position relationships between satellite and earth detector system. Unified parallel projection technology was proposed in this paper. Furthermore, we denoted that random optical distribution in laser-illuminated condition was a challenge for object discrimination. Great randomicity of laser active illuminating speckles was the primary factor. The conjunction effects of multi-frame accumulation process and some tracking methods such as Meanshift tracking, contour poid, and filter deconvolution were simulated. Comparison of results illustrates that the union of multi-frame accumulation and contour poid was recommendable for laser active illuminated images, which had capacities of high tracking precise and stability for multiple object attitudes.

Plasma produced by the radiation of a 1064 nm Nd:YAG laser focused onto a standard aluminum alloy E311 was studied spectroscopically. The electron density was inferred by measuring the Stark broadened line profile of Cu I 324.75 nm at a distance of 1.5 mm from the target surface with the laser irradiance of 3.27 GW/cm2. The electron temperature was determined using the Boltzmann plot method with eight neutral iron lines. At the same time, the validity of the assumption of local thermodynamic equilibrium was discussed in light of the results obtained.

Removing space debris by high-energy pulsed laser may be the most effective way to mitigate the threat posed by the increasing space debris. Laser ablation of a thin surface layer causes recoil impulse, which will lower the orbit perigee of space debris and accelerate the atmospheric capture. When the laser beam vertically irradiates a flat debris, it requires a certain laser fluence to reach the optimal impulse coupling, and the recoil impulse is parallel to the laser beam. However, the incident laser fluence varies in different parts of a non-flat surface. We have taken the shape effect into account to propose a numerical method of calculating the recoil impulse. Taking cylinder debris as the target, we have compared the recoil impulse in different laser fluences through simulation experiments, which implies that a higher laser fluence than the optimal one is needed to obtain a larger recoil impulse for irregularly shaped space debris.

In this paper, we demonstrate a narrow linewidth random fiber laser (RDFL), which employed a narrow-band fiber Bragg grating (FBG) to construct a half-open cavity and function as filtering element. Spectral linewidth down to 40 GHz has been measured. The maximum output power reaches 2.15 W at 1081.4 nm when 8.97 W pump light centered at 1036.5 nm is launched into the half-open cavity, which is more powerful than the previous reported results with ~100 mW output power.

Thermal control of the volume Bragg grating (VBG) in the LD with the external cavity is critical for the tuning of the wavelength and the narrowing of the bandwidth. Based on finite element theories, thermal properties of the VBG were researched under different conditions of LD illumining area, laser power, gratings’ working temperature and heat convection. Both the VBGs in the external cavity of LD bar and LD stack were considered in the experiments. The results show that higher working temperature of the VBG and adopting better heating convection cooling methods is beneficial to realize the uniformity of the VBG temperature distribution.

In this paper, a 15-direction ring laser diode array is chosen as pumping source in order to get uniform pump in laser medium. The diameter of laser rod is 15mm for obtaining high output laser energy. A numerical model of the side-pump pulsed Nd:YAG laser amplifier is set up. The finite element method using Ansys software is adopted to analyze the time-varying thermal effect. In order to find the temperature influence of the pump light’s distribution, the temperature distributions in laser rod loaded by 15-direction Gaussian beam and simplified uniform beam are calculated and the results are comparatively analyzed. Despite the highest temperature in laser rod is different, the whole variation trend is similar which indicates time-varying characteristic. The thermal lens effect is also calculated and the results indicate that the temperature gradient in the medium plays the most important role. This study could provide a simulation tool to evaluate the thermal effect of the laser amplifier.

The plasma channel evolution tendencies are studied numerically with the change of initial conditions based on the Nonlinear Schrödinger Equation. Then, the accuracy of an optical scheme to detect the plasma density inside the filaments is certified numerically. A Gaussian beam with pulse width 50fs, radius 2.5mm ranging energy from 10mJ to 50mJ at interval of 10mJ are simulated to yield plasma channel. With the augment of energy, firstly, the beginning position of plasma channel tend to be drew back gradually whereas the end position of the channel can be putted forward in a gradient form instead of continuously. Secondly, the number of peaks add one each time when the energy increase 10mJ. Lastly, the radius of plasma channel barely changes with initial energy up from 10mJ to 50mJ. On the other hand, plasma channel produced by a Gaussian beam with pulse width 50fs, energy 50mJ ranging the radius from 2.5mm to 10mm at interval of 2.5mm are simulated. With the increase of initial beam waist, the plasma channel length becomes shorter. The channel becomes broader and broader whereas the length of the channel becomes shorter. In order to verify the rationality of the approximation, Nornaraki detecting scheme through interference of the probe laser has been tested with the numerical simulation. As a consequence, the integral of refractive index along the radius direction can be replaced by the product of average refractive index and plasma channel diameter.

Resonant optical gyroscopes suffer serious performance degradation induced by noises. We propose using an air-gap silicon-on-silica slot waveguide ring resonator as the resonant cavity of a resonant integrated optical gyroscope. We estimate possible backscattering, Kerr effect, polarization fluctuation, and thermal drift in the air-gap slot waveguide. It is shown that the backscattering, Kerr nonlinearity, and thermal instabilities can decrease significantly compared to those in a common solid-core silicon waveguide cavity, and perturbations of the polarization fluctuation may be eliminated. In addition, a slot-waveguide cavity is more beneficial for integration than a photonic bandgap fiber cavity.

Wide band and low dispersion slow light in optofluidic infiltrated photonic crystal waveguide has been theoretically demonstrated. By adjusting the refractive indices of infiltrated optofluidic in the nearest two rows of air holes beside the defect waveguide and tuning the radius of bulk holes, the group index and bandwidth can be enlarged effectively at the same time. Considering the restricted variation of group index ng within ±10%, the flat band slow light at any group index from 17.80 to 77.55 with large normalized delay bandwidth product staying in the range of 0.32 to 0.36 has been obtained. The most attractive is that there is a stable bulk hole r=0.328a as the refractive index of second row holes n₂ changed for optimized slow light performances with large NDBP in large n_g range.

The third-order nonlinear optical properties of benzothiadiazole copolymer with triphenylamine derivative side chain (BCT) dissolved in chloroform are investigated by top-hat Z-scan and time-resolved pump-probe techniques with a picoseconds pulses laser at wavelength of 532nm. Organic polymers of triphenylamine have been widely applied to optoelectronic devices owing to its outstanding physics and chemistry characteristic. So its nonlinear optical characteristic is worth studying. The sample's excited-state dynamics can be detected by the pump-probe with phase object device with/without an aperture in the far field. We can determine the sample's nonlinear absorptive and refractive coefficient by the top-hot Z-scan device with/without an aperture in the far field. The experimental results show that the BCT has a good reverse saturation absorption and negative refraction. At the same time, the BCT showed up long excited-state lifetimes. By means of a five-level model and analyzing the experimental curves, all nonlinear optical parameters are obtained. With the proper lifetime and intersystem crossing time, this sample can be a candidate for optical limiting.

Based on combining material schemes and structure optimizing of two-dimensional triangular lattice photonic crystal, one methodology to improve slow light properties are proposed to support large NDBP at any group index in a photonic crystal line defect waveguide. Firstly, the effects of first and second row holes reflective indies n₁ and n₂ has been discussed, respectively. Then, one of the structural parameters, radius of holes in the first row r₁, has been adjusted to extend the range of group index with large NDBP. By properly adjusting various combinations of n₁ and r₁, the value of NDBP higher than 0.319 can be obtained at group index from 50 to 200. The design has shown the feasibility of post-fabrication technology to generate high performance slow light at any group index.

The third-order nonlinear optical properties of 1-(pyrene-1-y1)-3-(3-methylthiophene) acrylic keton named PMTAK was investigated by using Z-scan technique. The light sources for picoseconds(ps) and femtosecond(fs) Z-scan were a mode-locked Nd: YAG laser (21 ps, 532 nm,10 Hz) and an Yb: KGW based fiber laser (190 fs, 515 nm,532 nm, 20 Hz), respectively. In the two cases, reverse saturation absorption(RSA) are observed. The dynamics of the sample’s optical nonlinearity is discussed via the femtosecond time-resolved pump probe with phase object at 515nm. We believe that the molecules in excited state of particle population count is caused by two-photon absorption(TPA). The five-level theoretical model is used to analysis the optical nonlinear mechanism. Combining with the result of picosecond Z-scan experiment, a set of optical nonlinear parameters are calculated out. The femtosecond Z-scan experiment is taken to confirm these parameters. The obvious excited-state nonlinearity is found by the set of parameters. The result shows that the sample has good optical nonlinearity which indicates it has potential applications in nonlinear optics field.

A tunable nonreciprocal device is presented based on PT symmetry. This device structure is composed of two pairs PT symmetry ring. Signal λ1 is only transmitted in the forward direction, while another signal λ2 is transmitted in the backward direction. The signal channel spacing can also be controlled.

An SOI LDMOS device structure with Oxide By-passed(OB) was investigated and its breakdown mechanism and characteristic of structure was analyzed. Its performance was verified by 3D numerical simulation with SILVACO TCAD software. The simulated results show that the electrical field element of the device is modulated by the concept of similar Superjunction(SJ) structure. Compared with the SJ LDMOS device, OB LDMOS obtains the same breakdown voltage, simultaneously the specific on-resistance of the OB LDMOS reduces from 3.81mΩ·cm² to 1.96mΩ·cm², except for achieving comparable performance and overcoming the high aspect ratio of fabrication structure and the difficulty of accurate concentration match of SJ LDMOS.

In this paper, we have investigated the upconversion luminescence properties of Er³⁺ doped and Er³⁺/Yb³⁺ codoped potassium lithium tantalate niobate (KLTN) ceramics. The green, red, and near infrared upconversion photoluminescence properties are analyzed by the steady-state spectra under 980 nm laser excitation. We research the relationship between UC fluorescence integral intensity and Er³⁺ / Yb³⁺ concentration. We research the pump energy dependence of UC luminescence intensities, and summarize the changing trend for the slopes n with Er³⁺/Yb³⁺ ions concentrations. Finally, we make steady-state rate equations to describe the power dependence behavior and the UC mechanism. The deduced results is consistent with experimental results.

In order to weaken the chemical laser exhaust gas influence of the optical transmission, a vent pipe is advised to emissions gas to the outside of the optical transmission area. Based on a variety of exhaust pipe design, a flow field characteristic of the pipe is carried out by numerical simulation and analysis in detail. The research results show that for uniform deflating exhaust pipe, although the pipeline structure is cyclical and convenient for engineering implementation, but there is a phenomenon of air reflows at the pipeline entrance slit which can be deduced from the numerical simulation results. So, this type of pipeline structure does not guarantee seal. For the design scheme of putting the pipeline contract part at the end of the exhaust pipe, or using the method of local area or tail contraction, numerical simulation results show that backflow phenomenon still exists at the pipeline entrance slit. Preliminary analysis indicates that the contraction of pipe would result in higher static pressure near the wall for the low speed flow field, so as to produce counter pressure gradient at the entrance slit. In order to eliminate backflow phenomenon at the pipe entrance slit, concerned with the pipeline type of radial size increase gradually along the flow, flow field property in the pipe is analyzed in detail by numerical simulation methods. Numerical simulation results indicate that there is not reflow phenomenon at entrance slit of the dilated duct. However the cold air inhaled in the slit which makes the temperature of the channel wall is lower than the center temperature. Therefore, this kind of pipeline structure can not only prevent the leak of the gas, but also reduce the wall temperature. In addition, compared with the straight pipe connection way, dilated pipe structure also has periodic structure, which can facilitate system integration installation.

This paper describes a demonstration of a high power 888 nm end-pumped Nd:YVO4 picosecond regenerative amplifier operated at high repetition rate. By utilizing an all-fiber mode-locking picosecond laser as seed source and 888 nm continuous wave (CW) as pumping source, we obtained regenerative amplified output at 1064.07 nm with spectrum width 0.16 nm, pulse width of 38 ps, maximum power of 21 W, and the repetition rate is continuously adjustable from 300 to 500 kHz. The regenerative amplifier has high power stability and high compact structure.

In the paper, a decoupling method for homogeneous and dual-medium cells’ refractive index, and the entropy tomographic phase imaging method are proposed. Based on the decoupling method, the 3D morphology of sample can be obtained by the imaging method, which only needs two phase images of the cell. Thus the information about 3D refractive index distribution is given, and the 3D structure image of the model is reconstructed as well based on the relationship between the refractive index and thickness. In order to verify these methods, we set up the typical models after analysing the characteristic of blood cells, and the related orthogonal phase images are obtained by simulation experiment. Thus the 3D reconstructed structure images of the models are presented in this paper. Finally, the feasibility of this method is verified by simulating on a red blood cell and a monocyte model. The results show that subsurface imaging of samples can be achieved based on this method with a good accuracy.

A novel method for designing a silica waveguide based visible etched diffraction grating (EDG) with uniform loss is proposed. The designed 1st-order EDG comprises 121 output waveguides with a 2.5 nm channel spacing at a wavelength range from 400 nm to 700 nm. Using the conventional flat-field design with two-stigmatic-points method, the simulated channel loss non-uniformity of a conventional EDG is 2.66 dB. By changing the central output waveguide position and rotating the angles of grating facets according to an appropriately designed distribution function, the loss non-uniformity is reduced to 1.36 dB and the highest loss of marginal channels is decreased from 2.69 dB to 2.13 dB simultaneously. With a total chip size of 30 mm×16 mm, this visible EDG is suitable for realization of spectrometer-on-chip. The proposed design method can achieve insertion loss uniformity in a wide wavelength range with no additional element or extra fabrication step.

In this paper, we present the design of a 6 kW fiber-coupled laser diode system by using ZEMAX, and power scaling and fiber coupling techniques for high-power laser diode stacks were introduced in detail. Beams emitted from eight laser diode stacks comprised of four 960 W stacks with center wavelength of 938 nm and four 960 W stacks with center wavelength of 976 nm are combined and coupled into a standard fiber with a core diameter of 800 μm and numerical aperture of 0.22. Simulative result shows that the final power came out of the fiber could reach 6283.9 W, the fiber-coupling efficiency is 87%, and the brightness is 8.2 MW/ (cm²·sr).

The noise immunity of spectral detection is analyzed theoretically for the kind of chip spectrometer based on the combine of integrated filter matrix and sparse recovery. With the sparse representation algorithm, the mathematic model of the detection noise and condition number of filter matrix is built for the Gaussian shaped incident spectrum. In the simulations, the filter matrix with different condition number is produced by changing the cavity length with the fabry perot (FP) interference model. An exponential relationship between the spectrum recovery variance and the condition number is obtained, which is consistent with the built theory model. The result reveals that when the condition number of filter matrix is 10³ level, the noise tolerance of chip spectrometer will be as large as 10% when the variance is about 5 ×10^-3 in the sparse recovery.

The Laser drilling processes, in particular the interaction between the pulsed infrared Laser and the target materials were investigated on the CFRP composite laminate. The incremental freezing method was designed to reveal experimentally the temporal patterns of the ablation profiles in the CFRP composite laminates subjected to pulsed Laser irradiation. The temperature characteristics of the specimens were analyzed with Finite Element Method (FEM) and the phase change history studied. The theoretical results match well with the experimental outcome.

Dye-doped distributed feedback (DFB) structure is an essential structure for DFB laser. This paper presents an operative method to design a kind of dye-doped distributed feedback laser based on dye-doped holographic polymer dispersed liquid crystal (HPDLC) matrix. The results show that we have processed DFB structure of 10μm period, with a relatively low period deviation of less than 1%. Furthermore, we gain output characteristics of DFB structure through experimental methods, which show good characteristics for wide tuning range, narrow linewidth laser output production.

In the research of inertial confinement fusion, laser plasma interaction (LPI) is becoming a key problem that affects ignition. Here, multi-frequency modulation (Multi-FM) smoothing by spectral dispersion (SSD), continuous phase plate (CPP) and polarization smoothing (PS) were experimentally studied and equipped on SG-III laser facility. After using these technologies, the focal spots of SG-III laser facility can be adjusted, controlled and repeated accurately. Experiments on SG-III laser facility indicate when the number of color cycles adopts 1, imposing SSD with 3.3 times diffraction limit (TDL) did not lead to pinhole closure in the spatial filters of the preamplifier and the main amplifier with 30-TDL pinhole size. The nonuniformity of the focal spots using Multi-FM SSD, CPP and PS drops to 0.18, comparing to 0.26 with CPP+SSD, and 0.84 with CPP and wedged lens. Polarization smoothing using flat birefringent plate in the convergent beam of final optics assembly (FOA) was studied.

In this paper, electric field induced Pockels effect and optical rectification were demonstrated in the space charge regions of surface layers of (001)- and (110)-cut silicon crystals. The Pockels signals were much larger than the Kerr signals. These effects were considerable that they should be taken into account when designing silicon devices. Dependence of the optical rectification on various depth of the silicon crystal was investigated which could be used as a simple and nondestructive method to detect distribution of electric field of silicon devices.

Excimer laser in condition of high voltage, large current and fast discharge will produce strong electromagnetic pulse radiation and electromagnetic interference on the around electrical equipment. The research on characteristics and distribution of excimer laser electromagnetic radiation could provide important basis for electromagnetic shielding and suppressing electromagnetic interference, and further improving the electromagnetic compatibility of system. Firstly, electromagnetic radiation source is analyzed according to the working principle of excimer laser. The key test points of the electromagnetic radiation, hydrogen thyratron, main discharge circuit and laser outlet, are determined by the mechanical structure and the theory of electromagnetic radiation. Secondly, characteristics of electromagnetic field were tested using a near field probe on the key positions of the vertical direction at 20, 50, and 80 cm, respectively. The main radiation frequencies and the radiation field characteristics in the near field are obtained. The experimental results show that the main radiation frequencies distribute in 47, 65, and 130 MHz for electric field and the main radiation frequencies distribute in 34, 100, and 165 MHz for magnetic field. The intensity of electromagnetic field decreases rapidly with the increase of test distance. The higher the frequency increases, the faster the amplitude attenuate. Finally, several electromagnetic interference suppression measurement methods are proposed from the perspective of electromagnetic compatibility according to the test results.

The transmission characteristics of one-dimensional photonic crystal microring resonators are studied. Transmission spectra and field localization in the ring at resonant wavelengths are calculated. It is indicated that there is a relationship between the number of the periodic circular holes in the ring waveguide and the number of the field localization regions. When the number of the periodic circular holes is even or odd, the number of the localization regions is also even or odd. At the same time, the existence of the coupled-resonator-induced transparency is confirmed by the transmission spectra and field distribution in the ring.

With diode end pumped Nd:YAG directly and LBO intracavity frequency doubling, a compact, high efficient continuous wave blue laser at 473nm is realized. When the incident pump power reach 6.2W, 630mW maximum output power of blue laser at 473nm is achieved with 15mm long LBO, the optical-to-optical conversion efficiency is as high as 10.2%.

The polarization control(PC), as one of the important issues in photonic information technologies, has attracted great attention. In this paper, we proposed an efficient and compact polarization converter on silicon-on-insulator (SOI) platform based on asymmetrical direction couplers (ADCs). The ADCs consists of two parallel fully etched straight waveguides with different sizes in both width and height. This polarization converter can realize direct conversion between the TE₀ mode and the TM₀ mode with high conversion efficiency. Numerical simulations show that the present PC has a good fabrication tolerance for the variation of the waveguide width and height with high polarization conversion efficiency up to 82%.

As one of the most interesting II–IV compound semiconductors, ZnO has large band gap (3.37 eV) and high excitonic binding energy (60 meV). Based on this, it has attracted a great deal of attention for applications in ultraviolet light-emitting devices (LED) and photodetectors. There are many preparation methods to prepare ZnO films, such as metal organic chemical vapor deposition (MOCVD), magnetron sputtering, vacuum thermal evaporation, and so on. Among them, there are many advantages on using magnetron sputtering to form ZnO thin films, such as good adhesion, good thickness uniformity, high density of films, so we take advantage of this method in our experiment. In this work, we present a simple, rapid and cost effective method to fabricate ordered periodic substrates by preparing single layer polystyrene microspheres masks, with 300, 600, 800and 1100 nm in diameters. Then the layer of zinc oxide thin films on the mask by RF magnetron sputtering technique have been deposited, and two-dimensional zinc oxide nano-array samples were obtained at last. Using this active plasmonic substrate, the optical properties of ZnO films on polystyrene microspheres template has been investigated.

Compact, high power, and low-cost green laser light sources are needed in projection-related applications such as digital cinema, rear-projection television, simulators, and command and control stations. We report a LD array directly pumped intracavity SHG Nd:YVO₄/PPMgLN laser without lens or waveguide in this letter. A compact 3.12 W green laser was demonstrated by intra-cavity frequency doubled using a PPMgLN bulk crystal by a 19-emitter LD array pumped(single bar), the conversion efficiency from input LD array was 9.2%. A line-beam output suitable for laser projectors was generated, which has the potential to be scalable to small volumes and low costs for laser projection displays.

A master oscillator power amplifier (MOPA) is thought to be a suitable equipment to realize the power scaling for a diode pumped alkali laser (DPAL). In fact, the characteristics of a DPAL-MOPA system strongly depend on the central wavelengths of both a seed laser and a pump laser due to the extremely narrow nature linewidth for atomic alkali. In this report, a theoretical model of an end-pumped DPAL-MOPA system is first developed to study the influence of deviations in central wavelengths on the output features. Then, the relationship between the environmental parameters and the output linewidth as well as the output power is analyzed. The results reveal that the deviation in central wavelengths of both a seed laser and a pump LD will lead to a dramatic decrease of the output power for a DPAL-MOPA system. The conclusions are thought to be helpful for design of an end-pumped DPAL with high powers.

In this paper, the phenomena of plasma oscillations in silicon-based p-n junction photoelectric detector are researched. Starting from the classic Drift-Diffusion Model, the basic equations of photodetector with reverse bias under the radiation of femtosecond optical pulse were deduced. In our physical model, the carrier mobility in low electric field was introduced, and basic parameters including diffusion coefficients and damping coefficients were modified according to the nonlinear relation between carrier drift velocity and high electric field. A numerical algorithm base d on the finite difference method is proposed to solve the model. By solving the equations numerically, we obtained the transient dynamic behaviors of this kind of photoelectric detector, the current responses of the plasma oscillations phenomena, and the frequency of plasma oscillations, etc. By comparing the numerical solutions of plasma oscillations with approximate analytical solutions, we explored the reason for the difference between them.

In the recent years, alkali vapor lasers have become the most promising candidates for realization of a light source with both good beam quality and high output power because of their excellent performances. A rubidium laser is a typical kind of alkali vapor lasers. In this study, we developed a theoretical mode to evaluate the population densities of three levels as well as mode-matching efficiency of a rubidium laser pumped by a narrow-linewidth Ti:Sapphire laser under two different focal conditions. In the evaluation, at least two values of the output power of a rubidium laser must be known, which are usually obtained from the experiment. We performed a series of experiments by using two pump lenses with two focal lengths of 150 and 200 mm, and acquired two corresponding values of the laser output power. Then, we applied the experimental results in the theoretical calculation and then obtained the population densities of three levels and mode-matching efficiency of the rubidium laser. The study demonstrates that the outputted pump power can be used for evaluation of the population densities of three levels and mode-matching efficiency of an alkali laser under the different experimental conditions. The study might be valuable to better understand the physical features of an alkali vapor laser and to optimize the configuration of a high-powered alkali laser in the future.

A novel ultra-compact one dimensional (1D) photonic crystal (PC) nanobeam integrated sensor (1D PC NIS) is presented in this work, which is formed by series-connected 1D PC nanobeam bandstop filter (1D PC NBF) and 1D PC nanobeam cavity sensor (1D PC NCS). 1D PC NBF is based on an array of the same rectangular grating, with the photonics bandgap (PBG) range for 1538nm~1763nm. 1D PC NCS consists of a 1D PC nanobeam cavity, with the circle air-hole radius parabolically decreasing. By connecting these two parts above, the resonance within the stop band of 1D PC NBF will be filtered out, only the goal resonance used for refractive index sensing is left. Resonance wavelength position of the goal resonance remains the same basically. A high Q-factor of above 1.43×10³ and a high sensitivity of 127.07nm/RIU can be obtained simultaneously, which agrees well with the 122.07nm/RIU obtained above without filter. Moreover, benefiting from the ultra-compact size (0.7μm×11μm), 1D PC NIS proposed in the paper is promising to be used for sensors array and multiplexed sensing.

Laser diode end-pumped passively Q-switched Nd:YAG/Cr⁴⁺:YAG micro lasers, with short pulse width, high repetition rate, high peak power and compact structure, have widely applications in laser mico processing, optical communication, laser radar, medical and other fields. But its beam quality is not excellent because of short resonant cavity, thermal effect of crystal, and pump laser. The beam quality is promoted in this paper by compressing the pump beam size and confirming the best position of pump beam focus in crystal. The repletion rate of laser is 20kHz. The output single pulse energy is 18.2μJ and pulse width is 1.23ns. The beam quality of laser is M²=1.18.

In this paper, we present an experimental comparison of coherent beam combining (CBC) effect with different truncation factors based on a triangle fiber laser array for the first time to our best knowledge. First, we fabricate a triangle fiber laser array based on adaptive fiber optics collimators with the fixed focusing length of 0.18m and clear aperture of 50mm. Two output fiber arrays (6/125 fiber array and 20/400 fiber array) with different numerical apertures (0.12 and 0.065, respectively) are used to generate different truncation factors. The direct measurement method is used to measure the intensity distribution of the two collimated beams with different sizes. Results show that the beam diameters are 14.5mm and 27.6mm for 20/400 output fiber and 6/125 output fiber, separately. This means that two fiber laser arrays with truncation factors of 0.29 and 0.55 are achieved. Then we numerically calculate the CBC efficiencies of two situations with different truncation factors. The analytical results show that the CBC efficiency improves from 0.144 with truncation factor of 0.29 to 0.413 with truncation factor of 0.55. At last, a CBC experiment platform is set up. Throughout the whole experiment, single frequency dithering algorithm and SPGD algorithm are separately used to perform the phase-locking control and the tilt control. Two CBC experiments of triangle fiber laser arrays are achieved successfully both with residual phase errors about λ/15. By analysis the experimental results, we get the CBC efficiencies are 0.099 (69% of 0.144) and 0.264 (64% of 0.413) for the two fiber arrays. The experimental results identify the importance of truncation factor on CBC efficiency and provide an important reference on the selection of fiber array parameters in order to achieve the largest energy proportion in the central lobe.

A stable pulse-burst GdVO4/Nd:GdVO4 laser oscillator with repetition rate up to 500kHz is demonstrated by use of a pulsed diode-laser of Stabilized Wavelength 879nm as the pump source. While the pulsed 879nm LD was operated at the repetition rate of 100Hz and the pump duration was 1ms, the different output characteristics of pulse-burst GdVO₄/Nd:GdVO₄ laser were obtained by adjusting the repetition rate of A-O Q-switch. When the total pump energy was 120mJ, the pulse number of 100, 200 and 500, the burst energy of 25mJ, 35mJ and 40mJ, the pulse width of 8.5ns, 12ns and 27ns were achieved at repetition rate of 100kHz, 200kHz and 500kHz, respectively. The relative single pulse energies were reached to 250μJ at 100kHz, 175μJ at 200kHz and 80μJ at 500kHz. The peak powers were reached to 29.4kW at 100kHz, 14.6kW at 200kHz and 3.0kW at 500kHz. The M² factor was measure to 1.4.

This paper reports a study on the relationship between the combining efficiency and reflectivity of output coupler of diode array in spectral beam combining. The combining efficiency is analyzed theoretically by using principle of the resonator. The simulation shows that high reflectivity will lead to low combining efficiency, and low reflectivity may cause the failure of wavelength locking. With increasing of the reflectivity of the OC, the combining efficiency changes like a downward parabola which has a maximum value of ~10%. The experiments demonstrate that the highest efficiency is obtained at a reflectivity of 10%, and the experimental results agree well with the theoretical analysis.

Integration-Test-Bed(ITB) is China's first laser devices with single-beam ten-thousand joules output for Inertial Confinement Fusion (ICF) research. In this paper we describe the development of single-segment slab amplifiers for Integration-Test-Bed (ITB) with 400mm× 400mm aperture. The experiment results shows that the average small signal gain coefficient in 400mm×400mm aperture reach 5.28%/cm with the gain uniformity is about 1.09:1(maximum value/ average value), and up to 1.063:1 (maximum value/ average value) in 360mm×360mm beam-diameter clear aperture. The storage efficiency of system is about 1.47%. The pump-induced wave-front distortion is 5.3λ for the laser beams, which within the correction range of deformable mirror; the thermal recovery time was less than 4 hours. All of this guaranteed the output of 19.6kJ/5ns with wavelength of 1053nm from the Integration-Test-Bed (ITB) device.

We represent a design of a high brightness, fiber coupled diode laser module based on 16 single emitters at 915nm. The module can produce more than 150 Watts output power from a standard fiber with core diameter of 105μm and numerical aperture (NA) of 0.22. To achieve a high power and high brightness laser beam, the spatial beam combination and polarization beam combination are used to combine output of 16 single emitters into a single beam, and then an aspheric lens is used to couple the combined beam into an optical fiber. The simulation show that the total coupling efficiency is more than 95% and the highest brightness is estimated to be 11MW/ (cm²*sr).

This PDF file contains the front matter associated with SPIE Proceedings Volume 10152 including the Title Page, Copyright information, Table of Contents, Introduction, and Conference Committee listing.