Presentation + Paper
19 September 2018 Confocal microscopy for high-precision non-contact optical measurements
Author Affiliations +
Abstract
The EUV Snapshot Imaging Spectrograph (ESIS) is a slitless, tomographic imaging spectrograph for observing the solar transition region in extreme ultraviolet (EUV) at 63nm wavelength. An array of concave diffraction gratings re-image from the telescope prime focus to our CCD detectors. The instrument is aligned and focused in visible light, using substitute diffraction gratings ruled for the red HeNe laser line. To transfer precise alignment and focus of the visible gratings to the EUV gratings, we have developed a minitaturized, three point, noncontact measurement system, TEA (Transfer ESIS Alignment). TEA locates the grating surface using confocal microscopy, with three independent channels scanned together on a single stage, to specify the position and orientation of the spherical surface. Challenges for this measurement include the small size of the ESIS gratings (~ 16X20μm), their curved surfaces, diffraction effects, the alignment of tiny optics within TEA, and the mechanics used to repeatability mount the gratings. Our testing shows that the intrinsic repeatability of our measurement apparatus is approximately 2μm. In practice, however, our error is dominated by the process of mounting the grating subsystem in TEA, which introduces 12μm differences between subsequent runs. This level of repeatability meets our requirements for ESIS.
Conference Presentation
© (2018) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Micah A. Johnson, Charles C. Kankelborg, Rubin Meuchel, and Roy Smart "Confocal microscopy for high-precision non-contact optical measurements", Proc. SPIE 10747, Optical System Alignment, Tolerancing, and Verification XII, 107470A (19 September 2018); https://doi.org/10.1117/12.2319597
Advertisement
Advertisement
RIGHTS & PERMISSIONS
Get copyright permission  Get copyright permission on Copyright Marketplace
KEYWORDS
Extreme ultraviolet

Diffraction gratings

Confocal microscopy

Photodiodes

Microscopes

Beam splitters

Optical alignment

RELATED CONTENT

Multifocal confocal spectral microscope
Proceedings of SPIE (March 11 2015)
Developments in optical modeling methods for metrology
Proceedings of SPIE (June 14 1999)
Parallel confocal systems for biomedical application
Proceedings of SPIE (August 22 2001)
Holographic confocal microscope
Proceedings of SPIE (November 21 2003)
The Extreme Ultraviolet Sensor (EUVS) for GOES-R
Proceedings of SPIE (September 23 2009)

Back to Top