Q-Switch Pulse Estimator
Estimate Q-switched pulse duration, buildup time, and energy from cavity and gain parameters.
Q-switching generates short, energetic pulses by allowing population inversion to build under a high-loss cavity condition, then rapidly switching the cavity to low loss. The photon lifetime τ_c = 2L/(cδ) — where L is the one-way optical length, c is the speed of light, and δ is the round-trip loss including output coupler and internal losses — sets the fundamental pulse timescale. When the initial inversion ratio g_i = 2g₀l/δ exceeds one, pulses form with duration τ_p ≈ 3.5τ_c/(g_i − 1) and buildup time t_b. Enter cavity length, output coupler and high-reflector reflectivities, single-pass internal loss, small-signal gain, stimulated emission cross-section, beam area, and lasing wavelength to estimate stored energy, pulse duration, and peak power. Results assume an ideal fast Q-switch with uniform gain and approximately 60% extraction efficiency.