Nachweis schwacher Phasenmodulationen von Lichtbündeln

We describe a piezoelectrically tuned and electronically stabilized Michelson Interferometer. The use of a compensation method together with an appropriate modulation technique enables us to measure optical phase modulation Δϕ in light beams interferometrically with a resolution of Δϕ≈3·10⁻⁹ rad, where Δϕ stands for the rms value. The sensitivity of the instrument is limited only by shot noise

Detection of Weak Phase-Modulations in Light-Beams