Very high <i>Q</i> frequency-locked Fabry–Perot cavity

Abstract

We report measurements on a 1.75 m long Fabry–Perot cavity locked to a Nd:YAG tunable laser using the Pound–Drever technique. The cavity decay time was measured to be about 291 μs corresponding to a quality factor Q of about 5×1011, the highest value ever reported for an optical resonant cavity.