Actively Q-switched Nd:YLF laser emitting at 908 nm

An actively Q-switched quasi-three-level Nd:YLF laser emitting at 908 nm, for the first time to our knowledge, was demonstrated. A RTP double-crystal scheme was used to realize electro-optical Q-switcher, and a L-shaped cavity structure was designed to suppress parasitic oscillation at 1047 nm. An 806 nm laser diode was used as the pump source with about 480 μs pulse width. With 46.4 mJ pump pulse energy input at repetition rate of 100 Hz, maximum output pulse energies of 0.84 mJ and 0.73 mJ were obtained with output transmissions of 6.5% and 11%, respectively. The corresponding peak pulse powers were up to 14.3 kW and 12.1 kW, and the output pulse widths were 58.6 ns and 60.3 ns. The central laser wavelengths were both at 908.3 nm with spectral bandwidth of over 0.7 nm.

Injection-Seeded Terahertz Parametric Oscillator with a Ring-Cavity Configuration

This paper reports the characteristics of an injection-seeded terahertz parametric oscillator (TPO) with a ring-cavity configuration based on the MgO:LiNbO3 crystal. The ring cavity is constituted of three mirrors and the THz wave output surface where the pump and Stokes beams are totally reflected. The THz pulse energies and the Stokes pulse energies as functions of the pump pulse energy for different seed powers of 47.5 mW, 150.7 mW, and 312.8 mW were investigated. The experimental results showed that the injection-seeded ring cavity TPO exhibited the benefits of lower pump thresholds and higher output energies for the Stokes and THz waves. The smaller the pump pulse energy, the more obvious the effect of the seed injection. The reasons for the laser performance improvement were analyzed.

Studying the Effect of Laser Pump Pulse Energy and Delay Time on Conversion Efficiency of KTP

In this study, the effect of increasing pump pulse energy and delay time on the energy conversion efficiency of the Potassium Titanyl Phosphate (KTP) crystal at room temperature was investigated. It was found that the higher the pump pulse the greater the efficiency at a certain value of the delay time. Moreover, at the delay time 3.524ns, we found that the efficiency of the conversion of energy increases from 0.0112 to 0.0159. We also observed that the lower delay time between the pump and the probe pulses leads to increase the rate of energy conversion efficiency of the KTP crystal, where the reaches up to 3, which is higher than the value recorded in the absence of a pump pulse. The highest value of the rate of energy conversion efficiency recorded in this study was 0.0159. This work was achieved at room temperature.

Связь релаксации собственного стимулированного пикосекундного излучения GaAs с характерным временем остывания носителей заряда

During the powerful picosecond optical pumping of a thin (~ 1 µm) GaAs layer, a stimulated intense (up to 1 GW/cm^2) picosecond emission appeared. As was found, for a fixed density of the pump pulse energy, with an increase of its diameter the characteristic picosecond time τr of the emission and carrier density n relaxation increases. Due to interrelation of the density and the temperature of the carriers at high-intensity emission (in the saturation state of the emission amplification), time τr is associated with the characteristic temperature relaxation time τT of the photo-pumped carriers, which was determined earlier theoretically with the emission-caused carrier heating taken into account. The corresponding analytical expressions for τr as a functions of τT are consistent with the above experimental results.

Numerical study of few-cycle pulses generation from supercontinuum in ANDi-PCF

This paper presents the design of all-normal dispersion photonic-crystal fiber optimized for pulse-preserving supercontinuum generation near 800 nm. The supercontinuum generation is analyzed numerically addressing the role of pump pulse energy and the pump wavelength deviation from the zeroth point of third-order dispersion. We have also shown that supercontinuum generated in designed ANDi-PCF from a few nanojoule 100 fs pulses can be efficiently compressed down to a sub-10-fs pulse with a simple quadratic compressor.