Interferometric measurements with laser FM sidebands

Abstract

Hysteresis in piezoelectric transducers down to 20 Å and gas pressure changes as small as 10 mTorr are measured by locking a laser FM sideband to an interferometer resonance. In addition, rapid monitoring of large excursion motions with 200-Å accuracy is achieved using an "optical frequency comb" consisting of multiple FM sidebands.