FM and double modulation interferometry with sub-nanometer resolution using the iLens technique

We report a modulation technique applicable to optical two-beam interferometers with unequal arm lengths that allowsfor highly precise, low-noise displacement measurements below the nanometer regime with a compact optical layout.The technique is inspired by frequency modulation (FM) spectroscopy and employs an external electro-optic modulatorwith sinusoidally phase modulated laser light in the radio-frequency (RF) regime (MHz […]