We report a pulsed, widely tunable Ti:sapphire laser pumped by an all-solid-state Q-switched intra-cavity
frequency-doubled Nd:YAG laser with repetition rate of 7 KHz. Using two dense flint glass prisms as dispersion
elements, the output wavelength could be continuously tuned over 675-970 nm, with spectral line-width of 2 nm.
Gain-switching characteristics of Ti: sapphire laser shortened the pulse width to 17.6 ns. Well mode matching between
pump and laser beam in the sapphire crystal and thermal design of the cavity ensured stable, efficient laser operation.
The maximum output power was 6.2 W at 780 nm when the 532 nm pump power was 22 W; corresponding conversion
efficiency was 28.2%.
In this paper, we report on the near-field distribution of multi-core photonic crystal fiber lasers. The supermodes of
photonic crystal fibers with foursquarely and circularly distributed multi-cores are observed. The supermode properties
are investigated by using full-vector finite-element method (FEM). The mode operations of our 16-core foursquare-array
and 18-core circular-array photonic crystal fiber lasers are simulated by the COMSOL Multiphysics software. The
near-field distribution patterns of in-phase supermode are presented.
Multicore fiber lasers have larger mode areas, resulting in higher power thresholds for nonlinear processes such as
stimulated Raman scattering and stimulated Brillouin scattering. Because of longer distributed distance of the cores,
thermal mechanical effects are decreased compared with those of single-core lasers. Therefore, multicore fiber lasers are
proposed as a candidate for the power scaling. The progress of multicore fiber lasers is simply introduced. Optical fields
propagating in multicore fibers are coupled evanescently, resulting in what are called supermodes. In this article, the
coupled-mode theory for analyzing supermode of fiber transmission is introduced. By mean of the theory, assuming
under weak-coupling conditions, the supermodes are approximated as linear superposition of modes of individual cores
with appropriate coefficients. The near-field mode distributions of some supermodes are numerically calculated, and the
corresponding mode distribution patterns are drawn. For making the multicore fiber laser preferentially operate in a
particular supermode so that improving beam quality, an in-phase locking method based on self-imaging Talbot external
cavity is introduced.
Though controlling the coating reflectivity and intracavity diffraction loss, in the four cavity mirror configuration, a dual-wavelength continuous wave (cw) diode-side-pumped Nd:YAG laser that generates simultaneously at wavelengths of 1064 nm and 1319 nm is demonstrated. The relationship between power ratio of the two wavelengths and cavity length is studied. The cw dual-wavelength output power reaches 85 W when the average pump power is more than 500 W. The output power of respective wavelength exceeds 40 W, which is the best record as we know.
The article mainly focused on mobile on-line air quality monitoring system. By deeply analyzed DOAS theory, we designed this new air quality monitoring system. It is mobile and may monitoring many pollution sources on-line everyday.
The Differential Optical Absorption Spectroscopy (DOAS), based on the work by U. Platt and co-workers, is becoming increasingly popular for environment monitoring. DOAS may measure many trace gases like NO2, O3, BrO, NO3 , and SO2. It is designed for the measurement of primary and secondary urban air pollutants with high precision and little cross interference. In the DOAS technique, the spectrum of an artificial light source within a given bandwidth is measured after passing through the open atmosphere for between 100 m and 10 km. After removing the emission spectrum of the light source, the remaining differential absorption features are compared with the absorption cross sections of relevant trace gases. This allows both the qualitative and quantitative determination of their concentration in the light path.
After deeply research, we design this new system. It uses fiber spectroscopy, and it is mobile. User may monitor many pollution sources in a car. This makes auto-monitoring more easily.
Our DOAS system has these merits: New Light Emission-Receiver Unit which united emission,receiver and collimation lenses. New Background Elimination Fiber. And dynamic-feedback self-adapting program. In our experiment by this design idea, we get accurate data.
This letter reports the CW red laser radiation at 659.5 nm by intracavity frequency doubling a side pumped Nd:YAG laser with a KTP crystal (type II phase match, Θ=59.8°, Φ=0°). The thermal lens effect related to the laser crystal is analyzed and parameters of the three-mirror folded cavity are calculated. To enhancing the high gain at 1319 nm of the operating wave of Nd:YAG, the reflectivity of the mirrors is designed, and the red laser radiation at 659.5 nm is achieved by intracavity frequency-doubling. The generation of 1.2 W of the CW red laser beam is obtained with 260 W pumped power.
In this paper, high power and high efficiency operation of an all solid state, quasi-continuous-wave, Ti: sapphire laser is obtained with a laser diode pumped frequency doubled Nd: YAG laser. Discussing the output characters with three kinds of oscillate cavity, we acquire high output power, high light quality Ti: sapphire laser with flat to flat oscillate cavity. The maximum output power is 6.1W at 797nm with pump power of 27W, conversion efficiency is 22.6%, FWHM is 38.4ns and M2 is 3.6. Tuning by birefringent filter, all solid state titanium doped sapphire laser's output wavelength is from 750~950nm and average output power is 4.7W.
Pump-tuning method is very important and useful to OPO because it can relieve the OPO of any requirement for crystal translation or temperature variation. In this way, using PPLN crystal with poled period of 20.5mm, 1017~3384nm quasi-continuous-wave output is obtained pumped by Ti: sapphire laser which is tuned from 770 to 820nm. The maximum output power is 1.9W at 1208nm and conversion efficiency is 32%.OPO's average output power is 1.3W in whole output wavelength.
High-power red laser are of great interest in the fields of medical application, laser display and also as a pumping source for tunable lasers such as Cr:LiSAF. This letter reports the generation of a 12W Q-CW red laser beam by intracavity frequency-doubling of a Nd:YAG laser operating at 1.3μm with a KTP crystal. A laser module that consisting of a Nd:YAG rod side-pumped by thirty 20W LDs of a triangle radial pump geometry, a acousto-optic Q switch and a KTP crystal were used in the experiment. Because the efficiency of SHG is sensitive to the type II phase-matching angles of KTP, we calculate the value of phase-matching angles according to several of Sellemier equations of KTP, and modify the phase-matching angles to θ=59.9° and φ=0° by experiment. The maximum average power of 12W of red laser is achieved at 10KHz when the pump power of LDs is about 470W.
The stabilization and modes of a high-power intracavity frequency-doubled Nd:YAG laser are numerically analyzed, the great influence of frequency-doubler’s thermal lensing on the stabilization and modes of this laser is demonstrated, and a compensating method is developed. A high-power QCW 532 nm green laser has been fabricated in the experiment, with a KTP crystal (θ=90°, φ=24.7°, 6×6×9.2mm, cut for high-temperature (80°C) application) as frequency-doubler. With the KTP crystal warmed up to 48.8°C and resonator parameters adjusted optimum according to the calculated thermal focal length of KTP crystal, a maximum 110W green laser is generated at 10.6kHz repetition rate, and its pulse width is 142ns, instability 2%, and optical-to-optical efficiency 11%.
Disk fiber laser is a novel fiber laser. The pumping scheme of such type of fiber laser is side pumping by LD arrays and the pumping scale is large in comparison with the core pumping manner in a typical clad pumping scheme. More pumping power could be coupled into the disk and higher output power could be achieved. To optimize the system of disk fiber laser, it is necessary to analyze the parameter of each part of it. In this paper, the configuration factors that influence the pumping efficiency of disk fiber laser were analyzed and propagation of the rays in disk fiber laser was simulated using the method of BPM. In the process of simulation, the fiber was treated as cylindrical lens. The optimal position of pump resource is obtained with a fixed size of the fiber cross section.
Pico-second solid-state lasers with multi-watt average power and multi-kilowatt peak power are required for numerous applications such as UV generation and pumping of optical parametric oscillators for RGB laser TV display. In the past few years laser diode bars as pump source with continue output power of hundreds watts or more have become commercially available. LD side pumping YAG laser module can be used to generate high reputation mode locked output pulse with SESAM (Semiconductor Saturable Absorber Mirror) as an end cavity mirror. In this paper, we demonstrate an all solid-state mode-locked YAG laser with three-mirror folded cavity with a SESAM mirror, 80MHz pulse rate, about 10ps pulse width, and 2W 1064 nm output power. Thermal effect of laser rod, and polarization of intra-cavity beam are considered in laser cavity design. The enhancement of laser performance and decreasing Q switching effect are discussed. Further investigation is greatly needed.
This paper reports a high output power, high conversion efficiency, all-solid-state, quasi-continuous-wave Ti:sapphire laser system pumped by frequency-doubled Nd:YAG laser with DPL and by employing it as a pump source, we got the tunable broadband wavelength varying from 750nm to 950nm. Comparing with correlative research fields, two uppermost improvements were achieved, including the topmost output power and its broadband tuning. To ensure the ideal broadband output of Ti:sapphire laser, two sets of Ti:sapphire resonator mirrors were used respectively One is from 750 to 850nm, the other is from 850 to 950nm. Because the centric wavelength of the resonator laser is nearly 795nm, the maximum of the Ti:sapphire laser output power we obtained was 6W with the first set of mirror and the transmission rate of the output mirror is 10%. The power tops this field so far and the higher conversion efficiency is 22.2%. The second set of mirror we used can generate the output power of 3W, which is high enough to achieve broadband tuning for the future. And then, by using a tunable and line width compressed implement-birefringent filter which was Brewster angle placed, we achieved continuous tuning from 750nm to 950nm with reasonably high power.
We presented a diode end-pumped passively mode-locked Nd: YVO4 picosecond laser with a semiconductor saturable absorber mirror home made. Choosing a low-transmission output coupler and extending the cavity length suppressed the Q-switching mode-locked tendency in V-shaped cavity. We observed the pulse trains gone with a continuous background which was decreased with the decreasing of pulse repetition rate. The stable continuous mode-locked pulse was attained. The pulse repetition rate was 80.4MHz and the corresponding spectrum width was measured to be 0.15nm.
We present a theoretical study of a double microcavity resonators system with absorption or gain. The output intensity and the power intensity inside the microresonator are derived. Some interesting features and their possible application are discussed. The results may be useful for modulator, amplifier, laser and sensor.