This PDF file contains the front matter associated with SPIE Proceedings Volume 11564, including the Title Page, Copyright Information, and Table of Contents.

Based on the influence of surface metal materials on electric field, a terahertz metamaterial absorber with a highly symmetrical open box was designed. Aiming at the traditional square ring absorber, the absorber is made of three open square rings and a pair of symmetrical strips of silicon. Starting from the structure and material of the absorber, the absorption rate of the absorber to the three-frequency band wave is regulated by changing the size of the surface metal ring, changing the thickness of the dielectric layer, changing the dielectric constant of the dielectric layer material, and adjusting the conductivity of the silicon material after the addition of semiconductor silicon. When no semiconductor silicon is added, the absorption rate of the absorber in the low frequency band reaches 94.77% and the absorption frequency band is 0.73thz. By increasing the thickness of dielectric layer, the phenomenon of redshift is obvious, which can realize the purpose of continuous frequency band absorption. By adding the silicon strip with symmetrical structure and changing the conductivity comparison, it is found that it can close the absorption peak in the high frequency band, reducing the absorption rate to less than %, and at the same time affecting the absorption rate of the low frequency band.

In this paper, a one-dimensional photonic crystal with dielectric defect layer was studied in near-infrared band. For photonic crystal with only one defect layer, the effects of refractive index and thickness of defect layer, photonic crystal structure and incident angle on defect mode were discussed in detail. A photonic crystal structure with two defect layers was proposed, which had two defect modes in the forbidden band. The position of the two defect modes could be regulated by adjusting the number of photon periods and the thickness of the defect layer. Based on this structure, a twochannel narrow band filter was designed. The calculation results showed that the transmittance at the two defect modes of 1310 nm and 1550 nm reached 92.16% and 95.44%, respectively, while the full width at half maximum was only 5.5 nm and 9.7 nm. The simulation of the electric field distribution in the defect mode further proved the correctness of the design results. The research results had important value in the field of optical communication.

In this paper, a new structure of optical filter based on micro-ring resonator (MRR) and Bragg grating is proposed. The micro-ring resonator consists of two linear waveguides, one ring waveguide and two Bragg gratings. The filter has four ports. When optical signal input from one of the four ports, the output optical signals output from other three ports. The spectra of output ports of the optical filter are analyzed by using transmission matrix method. The result shows that the output channels of this optical filter are twice as large as that of the micro-ring resonator without Bragg gratings.

Herein, the optical and electrical property improvements of the InGaN MQW laser diode with an emission wavelength around 410 n1m are theoretically investigated by tuning the composition of AlGaN/GaN/AlGaN EBL, which is achieved with the simulation software Crosslight. The simulation results show that, compared with the reference structure (p-Al_0.2Ga_0.8N EBL), composition-graded AlGaN/GaN/AlGaN EBL structure A can increase the electron concentration in the quantum well, and ultimately increase the laser power, in which the Al content of EBL decreased from 0.2 to 0.05 along the growth direction. On the one hand, the height of EBL itself does not decrease compared to reference structure. On the other hand, gradually decreasing the Al content can reduce the polarization effect of the overall EBL, further increase the barrier height of EBL to electrons, resulting in reduced leakage current from 14.5% to 4.8% and increased output power by 0.28 times. For structure B, the EBL Al content increases from 0.05 to 0.2 in the growth direction, the barrier height of the EBL is significantly reduced, and a large amount of electrons leak into the EBL and p-GaN regions, resulting in an increase in leakage current. Therefore, the efficiency is significantly reduced compared to the structure A. The AlGaN/GaN/AlGaN composite EBL with gradually decreasing Al composition is an effective method to increase output power and suppress electron leakage in InGaN lasers.

In order to develop a fast and efficient method to produce structural colors on textiles, the structural colored textiles were successfully prepared. The formation mechanism of photonic crystal on textiles was proposed. The photonic crystals with structural color on textiles were fabricated by allowing a colloidal suspension of SiO₂ to deposit on textile fabrics through gravitational sedimentation. It was proved that the structural colors on polyester fabrics could be modulated by the size of colloidal microspheres, and the decrease in diameters of colloidal microspheres resulted in the blue-shift of structure color on the polyester fabrics. These results were well in accordance with Bragg’s law. The photonic band gap position of photonic crystals on polyester fabric was consistently confirmed by reflectance spectra of structural color. It is known that to form photonic crystals on textiles using gravitational sedimentation technology is an efficient and promising method on green printing and packaging industries.

In this paper, the direct bonding InGaAs/Si avalanche photodiode (APD) with certain gain is developed. This structure separates the optical absorption region (InGaAs) from the multiplication region (Si). Avalanche multiplication takes place in the Si layer after the carriers injected from the absorption region. InGaAs and Si wafer are connected together by wafer bonding technology. The interface quality of InGaAs / Si material is good through optimizing the physical and chemical cleaning methods and bonding conditions of InGaAs/InP and Si epitaxial wafers. The InGaAs / Si APD is fabricated by conventional semiconductor process. The gain of InGaAs / Si APD is 43 at 38V. Further optimization of the process can obtain lower dark current and higher gain bandwidth product. This kind of device can be used for long-distance optical fiber communication.

We propose and theoretically investigate a hybrid silicon/aluminum nitride waveguide on the SOI platform. The proposed scheme enables both piezomechanical interaction and optomechanical interaction within the hybrid waveguide. The microwave is piezoelectrically coupled to mechanical vibration in the optical waveguide through the deposited aluminum nitride. On the other hand, the light is coupled to the mechanical vibration through the radiation pressure and electrostriction. The simulation results show that near-unity internal conversion efficiency from the microwave domain to the optical domain can be achieved.

By using the finite difference method, the nonlinear effects of high repetition rate femtosecond pulse trains in silicon nanowire waveguides were analyzed. By numerically modeling the propagation of femtosecond pulse in silicon nanowire waveguides with the generalized nonlinear Schrödinger equation, the temporal and spectral properties of femtosecond pulses propagating are discussed, and the physical mechanisms of pulse evolution are demonstrated. The simulation results indicate that, owing to the remarkable nonlinear effect, the carriers in the silicon waveguide are rapidly excited with the increase of the input laser power, subsequently have significant modulation effects on the high repetition rate pulses train. For various repetition rate and power of the laser pulses train, the output pulsestrain will get different temporal compression and broadening under the dominance of different nonlinear effects. Furthermore, the results demonstrate that the spectrum evolution of pulse train with different transmission distances is similar to the calculated results of single pulse transmission. The results will provide an important reference for the design of optical sampling clock, microwave photonic radar system and the sweep of carriers in waveguide.

We design and experimentally demonstrate an all-optical analog to electromagnetically induced transparency with a Mach–Zehnder interferometer nanostructure with waveguides that are side-coupled to photonic crystal nanobeam cavities. When the phase difference between the two interferometer beams is designed to be odd multiples of π and the resonance peaks of the two cavities intersect, the transparency resonance occurs. The measured transparency linewidth is 0.6 nm, which is much narrower than the destructive interference linewidth carried out by the interferometer. When the phase difference between the two beams increases slightly, the destructive interference wavelength decreases accordingly and causes the transparency line shape to change into a Fano-like line shape. By replacing the single cavity with coupled cavities, multiple transparency phenomena can also be observed and further enhance the quality factor of the cavity.

Two types of patterned hybrid plasmonic waveguide structure are proposed to enhance the localization of light within a small modal area. With the presence of convex silicon ribs sandwiched between metal and highpermittivity material layers, the modal area can be dramatically reduced when compared with that of a normal hybrid plasmonic waveguide without significantly increased propagation losses. Analysis of the modal field distribution of the waveguides shows that this tight field localization is a result of the confinement in the vertical direction caused by the continuity of electric displacement field and horizontal confinement caused by mismatching of the wavevectors of the modes. An ultra-small modal area of less than one ten-millionth of the square of the wavelength can be achieved when using the proposed structure. These technologies are used in a ring resonator to demonstrate compact field confinement and an ultra-high-sensitivity sensor.

As a fundamental components for the integrated microwave photonic links, the nonlinear loss of the Silicon waveguides will significantly affect the links’ performance. We study the effects of the effective mode area (A_eff), two-photon absorption (TPA), free-carriers absorption (FCA), and linear propagation loss on the insertion loss in silicon waveguides. According to our simulations, the results show that it should be an efficient way to reduce the insertion loss of the silicon by combining the large mode area, small linear propagation loss and carriers sweep out techniques. And, we can also know that when the nonlinear loss will dominate with the coupled power becoming larger. Thus, the results can provide guidances on the gain, loss, and linear dynamic range of analog photonics links based on silicon waveguide.

As a new type of wind field detection technology, Doppler Asymmetric Spatial Heterodyne（DASH）can invert information such as atmospheric wind speed by monitoring the Doppler frequency shift of the absorption line or emission line of the atmospheric composition. It is widely used in the detection of middle and upper atmospheric wind fields. In this paper, a flexible support structure suitable for DASH interferometer is designed, so that the bonding process between different materials has a high safety margin in environmental testing. After modal analysis and random vibration analysis of the whole structure, the results show that the design meets the requirements. First, the fundamental frequency of the interferometer (765.79Hz>100Hz) meets the requirements of general satellites for the load; secondly, the random vibration analysis results show that the bonding stress between the surfaces is less than the allowable stress of the material (2MPa<14MPa), and it has a certain safety margin (>2); finally, the optical parts and structural parts did not collide with the structural parts during the vibration process, and the flexible structure did not undergo plastic deformation, and the whole structure of the interferometer was safe and reliable

An efficient design method based on the vector diffraction theory is presented for high numerical aperture achromatic imaging lenses (HADLs). Simultaneously achieving high numerical aperture and achromatic performance puts extremely demanding requirements on the design of HADLs. Therefor an efficient numerical technique is devised by combining the finite-difference time-domain (FDTD) method with improved binary search algorithm and thus sets up a routing to facilitate the smooth connecting between vector diffraction computing with optimizing iteration. Furthermore by taking advantage of lens symmetry when optimizing the phase transmission function, tremendous computational resources saves. By taking advantage of FDTD rigorous electromagnetic computing and choosing carefully parameters, search strategy and objective function, optimal solution is obtained and the search time is very short. To validate the proposed method, a HADLs with focal length f=3.5um and numerical apertures (NA) of 0.753 is designed and focusing efficiency of over 30% across the visible light wavelength is obtained by numerical evaluation. A brief comparing with scalar diffraction theory is also carried out.

Due to the hard and brittle nature for optical materials, such as single crystal silicon, sapphire and fused silica, it is still difficult to machine those materials directly. Laser assisted turning (LAT) is an advanced method for machining the optical materials, which improve the local cutting performance by softening the workpiece. It has been demonstrated the great potential in LAT process for improving the surface quality and reducing the cutting force. This study reviewed the recent application of LAT in these materials. The material removal mechanisms was also analyzed and summarized. According to the experimental results, the machining efficiency and tool life were significantly increased. Finally, the development trend of LAT is prospected.

Three types of gallium nitride (GaN) materials grown on sapphire (001) by metal chemical vapor deposition (MOCVD) were design for the study of different doping types on the characteristics of GaN epilayers. Surface photovoltage (SPV) spectroscopy of samples was measured in the photo energy range 2.9≤hv≤4.5eV with different chopping frequency. The similar surface photovoltage signals were obtained under sub-band-gap illumination in the photo energy range 2.9≤hv≤3.4 eV and the origins about signals were determined by comparing the surface photovoltage magnitude and phase spectra. By changing the incident light frequency, it can be found that the surface photovoltage magnitude shows a downward trend in the entire photon energy range, and the surface photovoltage magnitude has a more significant decrease in the sub-band gap region. In additional, a laser with 3.06eV photo energy was used to aid measured the surface photovoltage signals of sample with Si doped in the photo energy range 2.9≤hv≤4.5eV with chopping frequency at 172 Hz, 440 Hz, 1k Hz and 3k Hz. The defect states at the interface of the undoped GaN layer and Al₂O₃ were proved to be the major contribution to the SPV signals in the sub band gap region and were "slow processes" during the formation of SPV of the GaN samples.

A spatial light modulator based on sub-wavelength gold grating structure, named GLCoS by us, has been devised and tested to meet the challenge of the high space-bandwidth product in holographic video display. A sample GLCoS has been made and its display color appears green. However, if it is to be a device of a display system, its color characteristics must be further investigated, that is, its ability to display RGB color and its color purity. There are two MIM (Metal-Insulator-Metal) in the GLCoS, sub-wavelength gold grating plus liquid crystal cell and aluminum electrode forms a hybridized MIM and sub-wavelength gold grating itself is a MIM acting as an open-end TM-FP (TM-Fabry-Pérot) resonator. Based on our previous study involving GLCoS theoretical model, simulation software platform (FDTD plus CST Studio Suite) and an experimentally verified sample of single color, we seek an engineering way with simplicity and compatibility in the sense of the technique to investigate the red-green-blue (RGB) color display with GLCoS. Among the huge parameter space including the geometry and size of the structure, material, wavelength and light incident angle. We choose to change width of the slit, incident angle, LC (liquid crystal) birefringence to find the appropriate GLCoS spectral characteristics. The simulation results show that the dynamic modulation of the RGB phase can be achieved in the visible light band, and its amount of phase modulation is close to 2π and high chromatographic purity.

Bound states in the continuum (BICs) remain localized even though they coexist with a continuous spectrum of radiating waves that can carry energy away. These modes can be almost perfectly localized in the structure, making lasers working at BIC or quasi-BIC have an ultrahigh quality factor (Q) and hence low threshold. Lowcontrast gratings (LCGs) have better mode selectivity than high-contrast gratings and promise higher single-mode output power for LCG-based vertical-cavity surface-emitting lasers. A quasi-BIC (i.e. supercavity mode) with a Q factor of 9.2 × 10⁵ is obtained in the LCG, and a simplified three-layer slot laser with a Q factor of 9.66 × 10⁶ is constructed. Further, a law of using the period of a grating to control resonant wavelength and using etched depth and width to control Q factor can be used for designing a high-Q structure at a specified wavelength. The calculated Q factor is optimized systematically by changing various parameters, and the highest Q factor obtained reaches 2.81 × 10⁷ . The results of all these analyses are instructive to the design of grating-based low threshold electrically injected surface-emitting lasers or other high-Q devices.

The atomic spin co-magnetometer operating in the spin-exchange relaxation-free regime is a promising rotation sensor for its ultrahigh sensitivity to inertial forces. However, it was found that the bias magnetic sensitivity (BMS) of the comagnetometer was much larger than theoretically expected, making magnetic noise a dominant error. This paper reports on the experimental results of the effect of cell temperature on the BMS. It is found that the BMS increases rapidly as the cell temperature rises. This is attributed to the polarization gradient of atomic spins induced by the absorption of the pump beam by the atoms. The experiments and theory reveal that a high-power laser source for pumping is essential for the suppression of BMS and the improvement of bandwidth in the co-magnetometer.

In the continuous-variable quantum key distribution with real local oscillators, the reference pulses transmitted in the insecure quantum channel results in phase compensation noises on the homodyne detection of quantum signals. Traditionally, the phase compensation noise is modelled as a zero-mean Gaussian distribution for simplicity. However, it is more likely to be the one with non-zero mean in the actual environment. In this paper, the phase compensation noise is considered to be with a non-zero mean, and then the secure bound is analyzed according to the imperfect phase compensation noise model. The actual transmittance and excess noise are compared between the evaluation values derived from the theoretical analysis and the estimation values calculated by training signals. Simulation results show that the security analysis is consistent with the practical implementation, and the secret key rate decreases with the increasing mean value and noise variance.

A new design of compact zero-field atomic gradiometer was proposed and integrated using alkali vapor cell and customized optical components. This gradiometer used two parallel elliptically polarized lights, whose output intensity was measured to perform gradient magnetic field detection, respectively. To improve the gradiometer’s sensitivity of the magnetic field detection, the gradiometer was operated in the spin-exchange relaxation-free (SERF) regime. For the sensitivity study, the gradiometer was placed in a person-sized four-layer μ-metal magnetic shielding. With the magnetic shield closed up, the sensitivity of each channel was near 34 fT/ √ Hz, and the corresponding gradient sensitivity could reach 14 fT/√ Hz/cm on a 1cm baseline. When the cover of magnetic shielding was removed, the magnetometer sensitivity of single channel was about 90 fT/√ Hz, and the corresponding gradient sensitivity could reach 34 fT/√ Hz/cm. The experimental results implied that in a poor magnetic shielding environment, the performance of magnetometer was limited due to the fluctuations of the environmental magnetic field, while the gradiometer could work well.

Quantum illumination makes use of the strong correlation between entangled photons, making it possible to detect targets that break through physical limits. The Gaussian entangled state is a continuous variable entangled state with a high number of Hilbert spatial modes, which is currently a viable alternative to quantum lighting. In order to explore the target detection ability of Gaussian entangled state, this paper starts from the Gaussian entanglement model of Lloyd, establishes the target detection error probability boundary model under Gaussian entangled quantum illumination, and explores the optimal detection condition of Gaussian entangled state based on the detection signal-to-noise ratio and the number of measurements. The results show that when the Gaussian entangled state is optimal for the coherent state, the number of measurements is inversely proportional to the signal-to-noise ratio. Under the same error probability, the difference between the detection distances of the two states is determined by the atmospheric attenuation coefficient. The smaller the attenuation coefficient is, the smaller the attenuation coefficient is, the difference is greater.

The max-cut is used to solve maximum partition for given undirected weighted graph, the sum of the weights of all sides between the subset of vertex and complementary subset obtains a maximum value. Quantum adiabatic approximation is used to design system Hamiltonian H_sys, and the ground state of system Hamiltonian corresponds to the solution of max-cut problem. System Hamiltonian H_sys changes slowly along with initial Hamiltonian Hini follow the evolution path of Hamiltonian H_max, and then the ground state of Hamiltonian can be calculated. By analyzing the change of expected value with evolution time, one can judge whether the approximate solution is the optimal solution or not. In this paper, we test the adiabatic evolution of complete undirected graph with vertices from 6 to 14. Based on Python and Project Q package, we write a solver program that sets parameters according to the number of vertices and edges of undirected graph, and then obtain experimental results by measuring the state of qubits in quantum registers. It can be inferred from experimental results that for a complete undirected graph with less vertices, expected value can converge well, and then the optimal solution of max-cut problem can be obtained. When the number of vertices increase, the energy variation of Hamiltonian become more complex and the expected value is hard to converge.

Measuring the transverse relaxation time of noble gas nuclei with the Free-induction-decay (FID) signal is one of the key technical challenges and prerequisites for the nuclear magnetic resonance gyroscope (NMRG), which is a quantum sensor to form an inertial navigation system. In this paper, a novel method to estimate the parameter of the freeinduction-decay signal based on the adaptive internal model (AIM) controller is proposed and it is verified by the free induction decay data collected from the gyro prototype. In the proposed methods, the AIM con troller can provide estimates of the FID signal, such as the amplitude, the frequency, and the relaxation time. The feasibility of the scheme is proven by theoretical analysis and the reliability of the method is verified by the test results.

Microchannel plate (MCP) is an important compact two-dimension multiplier for parallel multiplication of charged particles. With the advantages of high temporal resolution, high spatial resolution, high electron gain and compact structure, microchannel plate has become an important potential readout device for cryogenic quantum computing, such as the quantum computation based on floating electrons of liquid helium surface. For the sake of ultra-fast reading, it requires the signal readout time is less than 10^-5 s at a temperature lower than 30K in the cryogenic quantum computing. However, the bulk resistance of MCP multiplier became giant at cryogenic temperature for the property of huge negative temperature coefficient of resistance, almost 10⁵ Gohm at 20K~30K, resulting in a readout time of 10^-2 -1s at cryogenic temperature, which was one of the major bottlenecks for the application of MCPs in the cryogenic quantum computing. In this paper, the bulk resistance of MCPs in two different bismuth contents (1at%, 2.4at%) under the same hydrogen reduction temperatures (730K) were present as the surrounding temperature controlled from 300K to 20K. The cryogenic bulk resistance of MCP was only decreased into 24% with the increase bismuth content from 1at% to 2.4at%, while thereof the normal bulk resistance was decline into 5%. The normal bulk resistance reduced only in the manner of improving the conductivity of conductive layer, could also increase the temperature-resistance sensitivity of MCP, leading an even greater temperature coefficient of resistance, which deteriorated the stability of readout in the cryogenic quantum computing.

This paper presents the design of a power amplifier (PA) used in a magnetic measurement system based on nitrogenvacancy (NV) centers in diamond. The core of the PA is CGH40035F from CREE, which can realize a larger output power and higher power added efficiencies (PAE) over wide frequency ranges. Through extensive source-pull and load-pull, the best load impedance and source impedance at the maximum output power are found, and the input and output impedance matching are achieved by the method of hybrid matching, which uses microstrip lines and capacitors. The simulation results show that the PA has a small-signal gain greater than 16 dB at 2.87 GHz, and the input return loss S₁₁ lower than - 17.7 dB. After calculation, the gain fluctuation in the 2.74-3.00 GHz is only 0.7 dB. Moreover, the output power of the 1 dB compression point P_1dB of the PA is 40.5 dBm with above 40% PAE, and the large-signal power gain is greater than 15 dB. The above data proves that the designed PA has extremely high performance and it is suitable for the manipulation of NV centers, which contributes to the integration of the magnetic measurement system.

Here we theoretically analyzed the impact of the laser uniformity on the magnetic sensitivity with the negatively charged nitrogen-vacancy (NV− ) centers in diamond. The maximum slope of the optically detected magnetic resonance signal was simulated under Gaussian laser excitation. The signal to noise ratio (SNR) with different integral radius was calculated. Results show that the SNR can be improved by selectively integrating the fluorescence within the optimal integral radius. The SNR can be improved by 16.4% under conditions that the average excitation rate is 69.6 kHz and Rabi frequency is 250 kHz. This method will benefit the sensitivity improvement of NV-based sensors with CCD detection.

In this work, we report an integrated configurable device, which successfully solved the synchronization problem of signals and provided the possibility for the “closed-loop” control of measurement. The digital part of the device is completely realized in the field programmable gate array (FPGA). According to the requirements of measuring arbitrary waveform generator(AWG) and high accuracy in the design of high-performance lock-in amplifier(LIA). the integrated and configurable design has more portable advantages in future practical applications. The device is suitable for measuring devices with quantum sensing and can be used in other measuring systems with weak signal. We design the arbitrary waveform generator and the lock-in amplifier in a digital circuit, and control the entire measurement system under the same clock, which can solve the problem of signal synchronization. The bandwidth of the output dual-channel arbitrary waveform generator can reach 30 MHz, The 4 V voltage signal is output through the operational amplifier and the signal is output as an analog quantity through a 30MHz low-pass filter. The designed arbitrary waveform generator can provide a reference signal for the lock-in amplifier. The lock-in amplifier adopts a double-channel orthogonal design, and finally uses the coordinate rotation method to calculate the final result.