Investigation of Piezoelectric Ringing Frequency Response of Beta Barium Borate Crystals

Polarization-insensitive wide-angle resonant acousto-optic phase modulator

Phase modulators are commonly used devices in optics. Free-space phase modulators are typically constructed from optically anisotropic crystals exhibiting the Pockels effect. To preserve the light's polarization state as it propagates through the crystal, it is essential to align the polarization and the angle of incidence of the light with respect to the crystal. In this study, we demonstrate the feasibility of constructing free-space resonant phase modulators with a broad acceptance angle and minimal dependence on the polarization state of light using an acousto-optic approach. These modulators operate in the megahertz frequency range, require modest power levels, have aperture sizes exceeding 1 cm2, and feature sub-millimeter thickness.

Active Suppression of Piezoelectric Ringing in Pockels Cells for Laser Cavity Application

Pockels cells used as electro-optical modulators in high-power high-repetition lasers suffer from piezoelectric ringing phenomenon due to piezoelectric properties of the crystals. A new method for active suppression of the piezoelectric ringing in Pockels cells is proposed in this work. It is based on symmetric control of Pockels cell using burst of short positive and negative voltage pulses with the same amplitude instead of a single long pulse for light polarization modulation. Rising and falling edges of pulses of the burst induce symmetrical acoustic waves of the opposite phase and cancel the piezoelectric ringing of the crystal. A new high voltage driver capable of generating positive and negative pulses of tens of nanoseconds of 3 kV magnitude was developed for this purpose. The amplitude of laser beam intensity pulsations caused by the piezoelectric ringing can be reduced up to five times when active suppression method is used for the deuterated potassium dihydrogen phosphate (DKDP) Pockels cell. Such crystals like DKDP, LiNbO3, and LiTaO3 may benefit from the proposed method and find new use in lasers of high repetition rate where piezoelectric ringing is a major limiting factor.

Electro-elastic features of Nd-doped YAl3(BO3)4 single crystal

The NYAB crystal shows relatively high resistivity and good temperature stability of piezoelectric activity, potential for high temperature piezoelectric applications.

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.

Crystal Growth of Multifunctional Borates and Related Materials

Crystalline materials play an important role in modern physics and electronics [...]