1. Ghost Beam Suppression in Deep Frequency Modulation Interferometry for Compact On-Axis Optical Heads.
- Author
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Gerberding, Oliver, Isleif, Katharina-Sophie, and Joo, Ki-Nam
- Subjects
- *
BESSEL beams , *LASER interferometry , *INTERFEROMETRY , *CUBES - Abstract
We present a compact optical head design for wide-range and low noise displacement sensing using deep frequency modulation interferometry (DFMI). The on-axis beam topology is realised in a quasi-monolithic component and relies on cube beamsplitters and beam transmission through perpendicular surfaces to keep angular alignment constant when operating in air or in a vacuum, which leads to the generation of ghost beams that can limit the phase readout linearity. We investigated the coupling of these beams into the non-linear phase readout scheme of DFMI and implemented adjustments of the phase estimation algorithm to reduce this effect. This was done through a combination of balanced detection and the inherent orthogonality of beat signals with different relative time-delays in deep frequency modulation interferometry, which is a unique feature not available for heterodyne, quadrature or homodyne interferometry. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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