@inproceedings{e404153622254d0fba9df541d6b2c51a,
title = "Homodyne displacement measuring interferometer probe for optical coordinate measuring machine with tip and tilt sensitivity",
abstract = "In this proceedings, we present a 3DoF (one linear, two angular) optical probe for measuring freeform optics in conjunction with an optical coordinate measuring machine (OCMM). This probe uses homodyne interferometry in a Michelson configuration and position sensing detection to simultaneously measure displacement, tip, and tilt. The goal of this work is to investigate point-to-point methods for measuring freeform optics and establish a probing methodology that can perform self-alignment with respect to the local optical surface. We present the design and preliminary benchtop validation of the probe's performance. Benchtop validation shows successful measurements with 5 nm linear and 20 μrad angular noise levels, with a 15 μm spot size. A CMOS sensor is used for visual confirmation of proper focus on measurement surface to minimize initial defocus error. A PSD detects linear horizontal and vertical displacement of the reflected beam from the measurement surface using autocollimation. In-phase and quadrature signals are measured by two photodetectors and post-processed to obtain displacement information. Periodic error caused by polarization effects and beam mixing is compensated by FPGA-based signal processing.",
keywords = "3DOF, angular interferometry, displacement measuring interferometry, freeform metrology, homodyne interferometry",
author = "Butler, {Sam C.} and Ricci, {Michael A.} and Chen Wang and Qun Wei and Ellis, {Jonathan D.}",
note = "Publisher Copyright: {\textcopyright} 2015 SPIE.; Optifab 2015 ; Conference date: 12-10-2015 Through 15-10-2015",
year = "2015",
doi = "10.1117/12.2195966",
language = "English (US)",
series = "Proceedings of SPIE - The International Society for Optical Engineering",
publisher = "SPIE",
editor = "Sebastian Stoebenau and Bentley, {Julie L.}",
booktitle = "Optifab 2015",
}