One fascinating thing about a pulsed laser is that, though the average power may be measured in watts or milliwatts, the peak power can easily reach millions of times that. This happens even in normal operation, but as [Les’ Lab] demonstrated, adding a Q-Switch can considerably enhance the peak power.

A Q-switch is an optical attenuator; when placed in the laser cavity, it keeps the cavity from reaching resonance. This greatly limits stimulated emission, allowing energy to build up in the chamber as the gain medium becomes increasingly saturated. Eventually, at some energy level, the Q-switch suddenly stops blocking light, and the cavity lases in a very short, powerful pulse. The Q-switch doesn’t increase the energy in a laser shot, but it does release it much more quickly. In this case, [Les] used chromium-doped yttrium aluminum garnet crystals as the Q-switch and compared performance across several different crystals.

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