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Free keywords:
Physics, Optics, physics.optics, Physics, Instrumentation and Detectors, physics.ins-det
Abstract:
To reach sub-picometer sensitivity in the millihertz range, displacement
sensors based on laser interferometry require suppression of laser-frequency
noise by several orders of magnitude. Many optical frequency stabilization
methods exist with varying levels of complexity, size, and performance. In this
paper, we describe the performance of a compact Mach-Zehnder interferometer
based on a monolithic optic. The setup consists of a commercial fiber injector,
a custom-designed pentaprism used to split and recombine the laser beam, and
two photoreceivers placed at the complementary output ports of the
interferometer. The structural stability of the prism is transferred to the
laser frequency via amplification, integration, and feedback of the
balanced-detection signal, achieving a fractional frequency instability better
than 6 parts in $10^{13}$, corresponding to an interferometer pathlength
stability better than $10^{-12}$ m$/\sqrt{\mathrm{Hz}}$.
