Tunable filters for JWST Fine Guidance Sensor

Details Tunable filters for JWST Fine Guidance Sensor Tunable filters for JWST Fine Guidance Sensor

Oct 2004

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2004spie.5487..676r&link_type=abstract

Optical, Infrared, and Millimeter Space Telescopes. Edited by Mather, John C. Proceedings of the SPIE, Volume 5487, pp. 676-6

Mathematics

3

Scientific paper

The Canadian contribution to the James Webb Space Telescope (JWST) mission will be the Fine Guidance Sensor (FGS), incorporating a science-observing mode using tunable filters. We describe here the requirements, the opto-mechanical design concept and bread-board test results for the JWST FGS tunable filters. The FGS requires two continuously tunable filters over the wavelength ranges 1.2 - 2.4 microns and 2.4 - 4.8 microns each having a spectral resolution in the range of R~70 to 200. The selected implementation uses dielectric coated Fabry-Perot etalon plates with a small air gaps. The design finesse is ~30 and the filters are used in 3rd order. The operating temperature is ~35K. Current coating designs provide implementations that require only five blocking filters in each wavelength range to suppress unwanted orders. The filters will be scanned via the use of low voltage piezo-electric transducers. We present results from cryogenic tests of coating samples, PZT actuators and a structural model. The PZT actuators were found have a displacement of ~3.3 microns at 30K with an applied voltage of 125V, more than sufficient for the required scan of the Fabry-Perot plate spacing. The prototype etalon coating was found to be very stable cryogenically, having a measured change of transmission of only ~1% at 77K. The same coating on a 12.7 mm thick substrate, similar to that planned for the filter, was found to have a 18 nm peak-to-valley surface figure change when cooled to 30K. These results demonstrate that the development of tunable filters for the JWST FGS is on track to meet the technology readiness requirements of the program.

Affiliated with

Also associated with

No associations

Rating

Tunable filters for JWST Fine Guidance Sensor does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Tunable filters for JWST Fine Guidance Sensor, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Tunable filters for JWST Fine Guidance Sensor will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1807274