The hybrid gas phase and solid state laser shows its inherent advantages in heat management and high efficiency and compactness, with DPAL becoming a perfect example. However, this kind of laser is limited by concern, for example, narrow absorption linewidth and a series of problems resulting from chemical reactions. As a matter of fact, Prof. Krupke proposed some hybrid gas phase and solid state lasers before DPAL, while they were chemically unfavored. As a newest type of hybrid gas phase and solid state laser, diode pumped nanoparticle gas laser (DPNGL) is a potential candidate in high power laser field. We put forward a rate equation model for Yb<sup>3+</sup> doped nanoparticle gas laser, and scattering of nanoparticles at the nano scale is included in this model. In addition, modifications of fluorescence lifetime and laser emission and pump absorption cross section are coupled into this model. Some vital factors are simulated and discussed. The results obtained from the modeling show that the influence of scattering is weak, and the Yb<sup>3+</sup> concentration is not necessarily high to achieve a good laser performance. The results are sufficiently positive for DPNGL to be a promising high power laser.
Alkali laser has been one of the most promising paths to high energy laser during past dozen years. As the first group realized DPAL and XPAL lasing in China, we had done lots of theoretical and experimental works to further clarify the mechanism of alkali lasers, such as exploring scaling parameters design balance and MOPA configuration amplified spontaneous emission suppression in DPAL based on our self-developed fast converging algorithm, XPAL’s continuous wave operation threshold, performance degradation of VBG narrowed diode laser array and stacks due to conductive thermal flow, heat deposition induced gas dynamic parameters variation estimation, local atomic number density change measurement with single frequency tunable diode laser, ionization and other higher level nonlinear effects with opto-galvanometer method. Based on above research works, preliminary c onsiderations and conclusions for alkali laser scaling are given.
Alkali laser has been one of the most promising paths to high energy laser during past dozen years. As the first group
realized DPAL and XPAL lasing in China, we had done lots of theoretical and experimental works to further clarify the
mechanism of alkali lasers, such as exploring scaling parameters design balance and MOPA configuration amplified
spontaneous emission suppression in DPAL based on our self-developed fast converging algorithm, XPAL’s continuous
wave operation threshold, performance degradation of VBG narrowed diode laser array and stacks due to conductive
thermal flow, heat deposition induced gas dynamic parameters variation estimation, local atomic number density change
measurement with single frequency tunable diode laser, ionization and other higher level nonlinear effects with opto-galvanometer method. Based on above research works, preliminary considerations and conclusions for alkali laser
scaling are given.
Diode pumped alkali vapor lasers (DPAL) is a rising high-energy laser. The wavelength of which is consistent with the response curve peak position of solar cell, and it has broad application prospects in laser directed energy transfer. The paper bases on the application of solar unmanned aerial vehicle (UAV) energy transfer in high altitude and longendurance conditions. For the first time by using the MODTRAN and FASCODE, we calculate the transmittance of Potassium, rubidium, cesium laser in the typical atmospheric conditions vertically and different angles of atmospheric slant path by the numbers, The result shows that DPAL has a very high atmospheric transmittance, and also a valuable reference in other applications with the atmospheric transmission.
An optical parameter oscillator base on KTP nonlinear optical crystals and a frequency doubling Nd:YAG lase was built. The wavelength of the signal light could be tuned from 750-800nm. At the wavelength of 780.2nm it could provide 62mJ each pulse with duration of 14 ns and spectrum (FWHM) about 0.4nm, and at the wavelength of 755nm the energy of each pulse was 10mJ with duration of 8ns. When the signal passed through a 10cm long Rb cell with Ar buffer gas at the temperature of 120°C and the wavelength was tuned from 779nm to 781nm, it could be observed that the fluorescence in the cell changed from dim to clear at first and then declined. Fluorescence could also be observed when the signal wavelength was 755nm and the cell was heated to 180℃. Which indicated that this OPO can provides over 1MW peak power for the research of rubidium lasers and rubidium-rare gas excimer lasers.
A strip Volume Bragg Grating (VBG) locked 64 emitter diode laser array’s center wavelength shift of each emitter
according to VBG’s local temperature is experimentally studied, which is consistent well with thermal imaging
temperature distribution, Finite element analysis (FEA) is then used to study strip and large area VBG’s temperature
gradients, we find even with minute heat deposition, due to PTR glass’s low heat conductivity, tens degrees temperature
gradient could easily be built, we suggest it may be partially respond for stack’s poor spectra narrowing performance
compared to single laser diode and diode array. Finally, some measures are further suggested to alleviate the effect.
The thermal effect produced by quantum defect is an important factor that affects the performance of DPAL. We
report on 3D simulation results of temperature distribution inside the alkali gain medium. The results show a
high and non-uniform temperature rise under CW pumped condition, and the current models that assume
uniform alkali density distribution needs to be modified. A convective cooling scheme should be applied for high
In this paper, a simple one dimensional heated flow analysis model and 3-D finite volume method (FVM) is set to
discuss the real gas dynamic effect in FDPAL. We found that huge amount of waste heat deposited in extreme compact
volume size will notably affect active medium’s local velocity, temperature and the density distribution along flow
direction, and would accordingly affect pump beam’s absorption and change optimized lasing conditions, hence, a
comprehensive model incorporate gas dynamic effect should be built for DPAL’s next stage development. We further
proposed that expanding fluid channel may be a choice to increase optical thickness along pumping direction and
alleviate this effect.
Excimer Pumped Alkali Laser (XPAL) is a hopeful choice to solve Diode Pumped Alkali Laser (DPAL)’s
disadvantages. Theoretical and experimental investigations of Rb-Ar XPAL were carried out in this paper. Time
dependent rate equation model illustrated that extreme pump strength was needed to exceed threshold and to assure
efficient cw running. 780nm lasing of four level Rb-Ar excimer was realized with a surrogate 15 ns pulsed optical
parametric oscillator (OPO). Possible resonator configuration may increase pumping strength was proposed.