100 kHz, 3.1 ns, 1.89 J cavity-dumped burst-mode Nd:YAG MOPA laser

Cavity-dumped burst-mode Nd:YAG laser master-oscillator power-amplifier system with a flat-top beam output realized by gain profile-controlled side pumping

We report a compact cavity-dumped burst-mode Nd:YAG laser master-oscillator power-amplifier system with a flat-top intensity distribution across the output-beam section. Custom-designed gain profile-controlled diode side pumping modules providing flat-top and concave gain profiles were utilized to generate a uniform beam profile and suppress thermal lensing during amplification, respectively. Bursts with an energy of 2.0 J and duration of 1.6 ms were operated at 10 Hz. Within the bursts, single pulses with an energy of 12.7 mJ and pulse width of 3.3 ns were achieved at 100 kHz.

30 mJ, 1 kHz sub-nanosecond burst-mode Nd:YAG laser MOPA system

We demonstrated a sub-nanosecond burst-mode MOPA Nd:YAG laser at 1.06 µm that consists of a cavity-dumped Q-switched master oscillator and a double-pass side-pumped amplification system. During the 1 kHz burst-mode operation, outputs with the single pulse energy of 29.8 mJ were obtained within the burst duration of 100 ms. The pulse width was 900 ps, which resulted in a peak power of 33.1 MW. During the 10 Hz operation, the single pulse energy reached 81 mJ with a pulse width of 900 ps, which resulted in a peak power of 90 MW.

Investigation of piezoelectric ringing effects in Pockels cells based on beta barium borate crystals

A detailed investigation of piezoelectric ringing and resonance effects in beta barium borate (BBO)-crystal-based Pockels cells in a pulse picker device is presented. Measurements mapping piezoelectric oscillation amplitude distribution in the aperture of BBO crystal are also performed. It is determined that in BBO Pockels cells, due to piezoelectric ringing and related effects, the optical contrast ratio is reduced by six to 70 times at certain (resonance) frequencies. Moreover, we demonstrate that in our pulse picker device, which uses a special sequence of control pulses (regeneration method) for the Pockels cell, at certain high-voltage control signal durations, piezoelectric oscillations can be suppressed, which significantly improves performance of the Pockels-cell-based laser pulse picker device at resonance frequencies: in such cases, the optical contrast ratio is stable and higher than 1000:1. Numerical simulation results support the experimental data.

Investigation of Piezoelectric Ringing Frequency Response of Beta Barium Borate Crystals

The piezoelectric ringing phenomenon in Pockels cells based on the beta barium borate crystals was analyzed in this work. The investigation results show that piezoelectric ringing is caused by multiple high voltage pulses with a frequency in the range from 10 kHz up to 1 MHz. Experimental investigation of frequency response and Discrete Fourier transformation was used for analysis. The method of piezoelectric ringing investigation based on the analysis of difference of real and simulated optical signals spectrums was proposed. The investigations were performed for crystals with 3 × 3 × 25 mm, 4 × 4 × 25 mm and 4 × 4 × 20 mm dimensions. It was estimated that piezoelectric ringing in the beta barium borate crystal with dimensions of 3 × 3 mm × 25 mm occurred at the 150, 205, 445, 600 and 750 kHz frequencies of high voltage pulses.