2021
Di Xu, * Zhenkun Wen; Rolland, Jannick P.
Verification of cascade optical coherence tomography for freeform optics form metrology Journal Article
In: Optics Express, vol. 29, no. 6, pp. 8542-8552, 2021.
Abstract | Links | BibTeX | Tags: CeFO, CEFO metrology, coherence, freeform, tomography
@article{XU2021b,
title = {Verification of cascade optical coherence tomography for freeform optics form metrology},
author = {Di Xu,,* Zhenkun Wen, Andres Garcia Coleto, Michael
Pomerantz, John C. Lambropoulos, 2 and Jannick P.
Rolland},
url = {https://opg.optica.org/oe/fulltext.cfm?uri=oe-29-6-8542&id=448922},
doi = {https://doi.org/10.1364/OE.413844},
year = {2021},
date = {2021-03-05},
urldate = {2021-03-05},
journal = {Optics Express},
volume = {29},
number = {6},
pages = {8542-8552},
abstract = {Freeform optical components enable dramatic advances for optical systems in both
performance and packaging. Surface form metrology of manufactured freeform optics remains
a challenge and an active area of research. Towards addressing this challenge, we previously
reported on a novel architecture, cascade optical coherence tomography (C-OCT), which was
validated for its ability of high-precision sag measurement at a given point. Here, we demonstrate
freeform surface measurements, enabled by the development of a custom optical-relay-based
scanning mechanism and a unique high-speed rotation mechanism. Experimental results on a flat
mirror demonstrate an RMS flatness of 14 nm (∼λ/44 at the He-Ne wavelength). Measurement
on a freeform mirror is achieved with an RMS residual of 69 nm (∼λ/9). The system-level
investigations and validation provide the groundwork for advancing C-OCT as a viable freeform
metrology technique.
},
keywords = {CeFO, CEFO metrology, coherence, freeform, tomography},
pubstate = {published},
tppubtype = {article}
}
Freeform optical components enable dramatic advances for optical systems in both
performance and packaging. Surface form metrology of manufactured freeform optics remains
a challenge and an active area of research. Towards addressing this challenge, we previously
reported on a novel architecture, cascade optical coherence tomography (C-OCT), which was
validated for its ability of high-precision sag measurement at a given point. Here, we demonstrate
freeform surface measurements, enabled by the development of a custom optical-relay-based
scanning mechanism and a unique high-speed rotation mechanism. Experimental results on a flat
mirror demonstrate an RMS flatness of 14 nm (∼λ/44 at the He-Ne wavelength). Measurement
on a freeform mirror is achieved with an RMS residual of 69 nm (∼λ/9). The system-level
investigations and validation provide the groundwork for advancing C-OCT as a viable freeform
metrology technique.
performance and packaging. Surface form metrology of manufactured freeform optics remains
a challenge and an active area of research. Towards addressing this challenge, we previously
reported on a novel architecture, cascade optical coherence tomography (C-OCT), which was
validated for its ability of high-precision sag measurement at a given point. Here, we demonstrate
freeform surface measurements, enabled by the development of a custom optical-relay-based
scanning mechanism and a unique high-speed rotation mechanism. Experimental results on a flat
mirror demonstrate an RMS flatness of 14 nm (∼λ/44 at the He-Ne wavelength). Measurement
on a freeform mirror is achieved with an RMS residual of 69 nm (∼λ/9). The system-level
investigations and validation provide the groundwork for advancing C-OCT as a viable freeform
metrology technique.