Equations · equation
Laser Rate Equations
Photonics · 1960
- Equation
- dN/dt = P − N/τ − B·N·φ · dφ/dt = B·N·φ − φ/τ_c
- Field
- Photonics
- Named After
- Hermann Statz · George deMars
- Year
- 1960
Symbols
N population inversion (excited atoms) · φ photon number in the cavity · P pumping rate · τ excited-state lifetime · τ_c cavity photon lifetime · B stimulated-emission strength
Significance
The laser as a ledger: pumping fills the upper level, photons breed photons off the inversion, the cavity leaks. Above a pump threshold the light term runs away and the cavity blazes coherently — written in the very year Maiman's ruby laser first flashed, and still how engineers model everything from laser pointers to fiber amplifiers.
Referenced by
element
equation
Open on the Equations shelf — the interactive card, the filters, and everything alongside it.