The electro-optic Q-switch can be used to adjust the loss in the laser cavity to generate high-intensity pulsed laser. When an electromagnetic field acts on a photoelectrically active crystal, such as lithium niobate crystal (LN), the change in refractive index is proportional to the electric field, the so-called Pockels effect. Light passing through the active crystal undergoes a phase change proportional to the length of the interaction, thereby changing its polarization. By placing the crystal between a pair of crossed polarizers, light can pass or block at very fast switching speeds. This makes lithium niobate crystals often used to create a Pockels Cell to adjust the light intensity in the laser cavity to achieve Q-switching and generate very short, intense laser pulses.

WISOPTIC’s LN crystals provide low loss, high contrast, low wavefront distortion, and meet the use conditions of 100~250MW/cm2. The temperature-stable version of the electro-optic LN Pockels cell allows operation in a wide range of temperatures while maintaining good extinction ratio. LN Pockels cells can be used in both military and commercial applications, including target position transmission systems, laser ranging, and eye surgery. When used in a transverse electric field perpendicular to the optical axis or Z-axis, lithium niobate can exhibit high extinction ratio, extremely low transmission loss, low switching voltage and constant temperature in a large temperature range. The characteristics of these crystals, combined with expertise based on the growth of lithium niobate crystals and excellent anti-reflective (AR) coatings, make them ideal for military reinforcement and industrial applications.

A high-quality E-O Q switch has several important characteristics:

- Very low loss in the “off” state to maximize output intensity

- High contrast ratio in “on” and “off” states

- Able to withstand very high peak laser power