Frequency shifts of laser standards with external absorbing cell in Fabry–Perot cavity

Abstract

We describe theoretically the form of non-linear absorption resonance used for the frequency stabilization of laser standards, when the absorber is placed in an external Fabry–Perot (FP) resonator. We calculate the frequency shifts induced by diaphragms located outside the FP resonator. The resulting shifts can be of the order of magnitude 10 −3–10 −2 γ, where γ is the width of non-linear resonance. They strongly depend on the transit time phenomenon, which even changes the sign of the shift in the transit time limit.