Laser Q-Switching Pulse Energy Calculator
Solid-state laser dynamics: Calculate Q-switched giant pulse energy (E_p), peak optical power (P_peak), pulse duration (FWHM), and population inversion dynamics (Wagner-Lengyel).
Laser Medium & Pumping Inversion
Giant Pulse Characteristics
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Frequently Asked Questions
How does Q-switching generate megawatts of peak power?
A Q-switch initially introduces high optical loss into the laser resonator (low Q), preventing stimulated emission while optical pumping pumps the crystal to a massive, unnatural population inversion. When the Q-switch is suddenly turned transparent (high Q), the stored energy discharges in an avalanche burst of stimulated emission, releasing all photons in a few nanoseconds.
What is the difference between active and passive Q-switching?
Active Q-switching uses an externally triggered Pockels cell (electro-optic) or acousto-optic modulator (AOM) to precisely control firing timing and repetition rate. Passive Q-switching uses a saturable absorber crystal (such as Cr⁴⁺:YAG), which bleaches transparent automatically when the intracavity intensity reaches saturation, creating compact, self-firing pulses.
Why does a shorter laser cavity produce shorter Q-switched pulses?
Pulse duration is proportional to the photon cavity lifetime τ_c = 2L / (c · Losses). A shorter physical cavity (L) allows photons to make round-trip passes between mirrors much more rapidly, speeding up the avalanche build-up and decay of the optical pulse.