The paper presents the research and development of a low-volume brightness amplifier for imaging laser active optical systems (laser monitors) with a pulse repetition frequency (PRF) of up to 100 ...kHz. A small-sized active element and pumping source based on tasitron have been developed. The effect of the brightness amplifier’s operating features (concentration of CuBr and HBr) on the numerical characteristics of images obtained in the laser monitor has been studied. The optimal concentrations were determined, and it was proven for the first time that they should be 30% lower than what is needed for obtaining maximum laser power. It was shown that increasing the CuBr concentration leads to a decrease in the field of view. The effect of the one-pass amplification profile on the quality of LOAS-based images was experimentally determined. A small-sized active element (40 cm3) excited with a specific pulse energy input of 238 μJ/cm3 can be used to obtain images with a time resolution of up to 10 μs.
•100 kHz CuBr low volume brightness amplifier was developed.•The optimal operating mode of the active element is determined and provided by lower concentration of CuBr and HBr in active medium.•The field of view of laser monitor determined by the beam profile of brightness amplifier and can be increased by decreasing CuBr concentration.
One of the key challenges in the design of gas lasers powered by pulsed power circuits pertains to reducing the flow of current through the electrodes during the filamentary discharge phase. This ...phase occurs after the lasing period ("volume glow") is terminated due to discharge instabilities and the current flow during this period is referred to as late currents. Late currents contribute to electrode erosion. The ejected electrode material contaminates the gas, and lowering the service life of the laser. Snubber circuits are an economic solution to reducing late currents in pulsed power circuits that do not employ a magnetic switch. In a simple snubber, which is connected directly across the main storage/drive capacitor <inline-formula> <tex-math notation="LaTeX">C_{0} </tex-math></inline-formula>, it was found that the stray series inductances of both <inline-formula> <tex-math notation="LaTeX">C_{0} </tex-math></inline-formula> and the high voltage snubber diodes significantly reduced the magnitude of current flowing through the snubber. A new coaxial capacitor and snubber assembly was proposed to improve the effectiveness of the snubber in reducing the late currents. The design exploited the high degree of mutual coupling between the concentric coaxial cylinders to reduce the total inductance in the snubber loop. Experimental results showed an almost 40% reduction in the total charge that flows through the discharge in the late currents stage. Although the improvement was significant, it is expected that improvements to the construction quality of the prototype could potentially lower the late currents even further.
Long pulse gas lasers utilizing double-discharge circuits are different from the single-short pulse gas lasers in that they do not require all of the desired energy to be deposited into the peaking ...capacitors prior to ignition of the main gap. Instead, the majority of the energy is held in another capacitor that is then discharged in the form of a longer duration discharge pulse output compared with that of single-short pulse lasers. Extended stability of the discharge is typically achieved by igniting the main gap discharge at higher ignition voltages. Several double-discharge circuit topologies exist in the literature. However, each topology has its own disadvantages primarily centered around the components needed and the resulting complexity. In this article we introduce the application of the new hybrid circuit pulsed power topology as a double-discharge circuit with high ignition voltages. The hybrid circuit pulsed power topology was originally published by the authors of this article in their previous publication titled "A New Hybrid Pulsed Power Circuit Topology for Gas Laser Applications." The advantage of the hybrid circuit as a double-discharge circuit is that it does not require any special device e.g., semiconductor opening switch (SOS) diode and can use commonly available components.
In this paper, the tendency is towards looking for a correction factor in the diffraction loss from (TEM01) in order to search for the same parameters, diffraction loss in a cavity has standing ...(TEM01) modes. This will be through a lengthy analysis in the far-field intensities the waves via – Gaussian beam shaped wave patterns. The analysis is in the same criteria as that of (TEM00) modes, except for a little complicating factor in the round-trip by pass on the surface of the aperture mirror. The results showed that the diffraction loss procedure is just the continuate for the earlier work, except that the field intensities change for TEM01, as that of TEM00, as such, it has a direct effect on the equation fitting it. The Combination of experimental and Theoretical results in this study are in excellent agreement as in g = 0.80 and they were both functions of the physical parameters of the active medium and the laser resonator.
We reported here a high-efficiency, high peak-power, narrow linewidth 1.9 μm fiber gas Raman amplifier based on stimulated Raman scattering (SRS) in an H 2 -filled antiresonance hollow-core fiber. A ...CW seed fiber laser near 1908 nm is amplified by the first vibrational Stokes wave of hydrogen molecules while pumping with a pulsed 1064 nm microchip laser. The seed laser significantly enhances the vibrational SRS and suppresses the rotational SRS, resulting in a record optical-to-optical conversion efficiency of ~41% (quantum efficiency ~73.5%) for such H 2 vibrational Raman experiments in hollow-core fibers, with 1.4 m fiber and only 3 bar H 2 , which is more preferable in applications. The maximum average Stokes power of 74.2 mW and the peak power of ~150 kW with the linewidth about 1 GHz (~12 pm) are obtained. The linewidth characteristics of such fiber gas Raman laser sources are systematically studied for the first time by experimental methods. This paper provides an effective method to obtain efficient 1.9 μm fiber sources of both high peak power and narrow linewidth.
The paper presents the results of the research and development the brightness amplifier excited by longitudinal capacitive discharge with a pulse repetition frequency (PRF) up to 24 kHz for using in ...systems with optical signal amplification. The amplification features of the active element were experimentally studied. The results of the use the designed brightness amplifier in the MOPA system and in the laser monitors (bistatic and monostatic) demonstrate the efficiency of the designed active element for an optical signal amplification. The effect of the vapor concentration in the medium on image brightness amplification characteristics was experimentally estimated. The concentration of the CuBr vapors should be lower to provide the optimal features of laser monitors. The difference between concentration provided maximum output power and optimal active optical system parameters reaches 25%–30%. The contrast of the images in the monostatic and bistatic laser monitors higher 90%.
•CuBr brightness amplifier excited by longitudinal capacitive discharge was developed.•The effect of the vapor concentration in the medium on image brightness amplification characteristics was experimentally estimated.•The results of the use the designed brightness amplifier in the MOPA system and in the laser monitors (bistatic and monostatic) are presented.
Liquid crystal (LC) device has high tunability with low power consumption and it is important not only in visible region but also in terahertz region. In this study, birefringence and absorption ...losses of hydrogen-bonded LC was estimated at 2.5 THz. Our results indicate that introduction of alkoxy chain to hydrogen-bonded LC is effective to increase birefringence in terahertz region. These results indicate that hydrogen-bonded LCs are a strong candidate for future terahertz devices because of their excellent properties in the terahertz region.
—Collisional broadenings and shifts of argon lines at 811.5 nm and 912.3 nm relevant to the lasing cycle of an optically pumped rare gas laser (OPRGL) are calculated. The calculations are based on ...the Lindholm–Foley theory and van-der-Waals potential. The results allowed estimation of the validity of previously measured broadening and shift coefficients of these Ar lines in pure gas and Ar–Ne mixture.
We report here the first hundred-watt continuous wave fiber gas laser in H2-filled hollow-core photonic crystal fiber (PCF) by stimulated Raman scattering. The pump source is a homemade ...narrow-linewidth fiber oscillator with a 3 dB linewidth of 0.15 nm at the maximum output power of 380 W. To efficiently and stably couple several-hundred-watt pump power into the hollow core and seal the gas, a hollow-core fiber end-cap is fabricated and used at the input end. A maximum power of 110 W at 1153 nm is obtained in a 5 m long hollow-core PCF filled with 36 bar H2, and the conversion efficiency of the first Stokes power is around 48.9%. This work paves the way for high-power fiber gas Raman lasers.
The novel and sensitive In-Gas Laser Ionization Spectroscopy (IGLIS) technique enables high-precision laser spectroscopy of the heaviest elements and isotopes very far from stability that are ...produced in fusion-evaporation reactions at in-flight separators. Powerful and dedicated laser systems are required in these facilities to realize in-gas jet laser spectroscopy with optimal spectral resolution and efficiency. The performance with respect to the requirements for IGLIS studies at the low energy front-end of the Super Separator Spectrometer (S3) at GANIL, France, of Dye and Ti:sapphire laser systems is investigated. In addition, a number of specific experimental cases on key isotopes of the elements Ag, Sn, Ac, and No are discussed in detail.
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