Recent developments in high resolution saturation spectroscopy obtained by means of acousto-optic modulators

TLDR

The study presents three applications of acousto‑optic modulators in high‑resolution saturation spectroscopy: improving laser stabilization, detecting saturation resonances, and enabling line‑shape studies with a single laser. The authors use acousto‑optic modulators to (i) stabilize Ar⁺ laser frequency and amplitude outside the resonator, (ii) detect saturation resonances via a frequency‑shifted, modulated beam that yields high signal‑to‑noise and background cancellation, and (iii) perform line‑shape studies with a single laser.

Abstract

We present three applications of acousto-optic modulators to high resolution saturation spectroscopy. — First, an A/O modulator is used to improve both frequency and amplitude stabilization of Ar+ lasers outside the laser resonator. — Second, a new technique to detect saturation resonances is demonstrated. In this method the saturation beam is both frequency shifted and modulated and the induced modulation of the probe beam is detected resulting in a highly improved signal to noise ratio and a high degree of background cancellation. — Third, an auxiliary A/O modulator is used for line shape studies with a single laser.