Abstract
Fibre Bragg grating (FBG) OH suppression is capable of greatly reducing the bright sky background seen by near infrared spectrographs. By filtering out the airglow emission lines at high resolution before the light enters the spectrograph this technique prevents scattering from the emission lines into interline regions, thereby reducing the background at all wavelengths. In order to take full advantage of this sky background reduction the spectrograph must have very low instrumental backgrounds so that it remains sky noise limited. Both simulations and real world experience with the prototype GNOSIS system show that existing spectrographs, designed for higher sky background levels, will be unable to fully exploit the sky background reduction. We therefore propose PRAXIS, a spectrograph optimised specifically for this purpose.
The PRAXIS concept is a fibre fed, fully cryogenic, fixed format spectrograph for the J and H-bands. Dark current will be minimised by using the best of the latest generation of NIR detectors while thermal backgrounds will be reduced by the use of a cryogenic fibre slit. Optimised spectral formats and the use of high throughput volume phase holographic gratings will further enhance sensitivity. Our proposal is for a modular system, incorporating exchangeable fore-optics units, integral field units and OH suppression units, to allow PRAXIS to operate as a visitor instrument on any large telescope and enable new developments in FBG OH suppression to be incorporated as they become available. As a high performance fibre fed spectrograph PRAXIS could also serve as a testbed for other astrophotonic technologies.
| Language | English |
|---|---|
| Title of host publication | Modern Technologies in Space- and Ground-Based Telescopes and Instrumentation II |
| Editors | Ramón Navarro, Colin R. Cunningham, Eric Prieto |
| Place of Publication | Bellingham, WA |
| Publisher | SPIE |
| Pages | 84501V-1-84501V-6 |
| Number of pages | 6 |
| Volume | 8450 |
| ISBN (Print) | 9780819491510 |
| DOIs | |
| Publication status | Published - 2012 |
| Externally published | Yes |
| Event | Modern Technologies in Space- and Ground-Based Telescopes and Instrumentation II - Amsterdam, Netherlands Duration: 1 Jul 2012 → 6 Jul 2012 |
Other
| Other | Modern Technologies in Space- and Ground-Based Telescopes and Instrumentation II |
|---|---|
| Country | Netherlands |
| City | Amsterdam |
| Period | 1/07/12 → 6/07/12 |
Fingerprint
Keywords
- Fibre Bragg grating
- Infrared
- OH suppression
- Spectroscopy
Cite this
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PRAXIS : a low background NIR spectrograph for fibre Bragg grating OH suppression. / Horton, Anthony; Ellis, Simon; Lawrence, Jon; Bland-Hawthorn, Joss.
Modern Technologies in Space- and Ground-Based Telescopes and Instrumentation II. ed. / Ramón Navarro; Colin R. Cunningham; Eric Prieto. Vol. 8450 Bellingham, WA : SPIE, 2012. p. 84501V-1-84501V-6 84501V.Research output: Chapter in Book/Report/Conference proceeding › Conference proceeding contribution › Research › peer-review
TY - GEN
T1 - PRAXIS
T2 - a low background NIR spectrograph for fibre Bragg grating OH suppression
AU - Horton, Anthony
AU - Ellis, Simon
AU - Lawrence, Jon
AU - Bland-Hawthorn, Joss
PY - 2012
Y1 - 2012
N2 - Fibre Bragg grating (FBG) OH suppression is capable of greatly reducing the bright sky background seen by near infrared spectrographs. By filtering out the airglow emission lines at high resolution before the light enters the spectrograph this technique prevents scattering from the emission lines into interline regions, thereby reducing the background at all wavelengths. In order to take full advantage of this sky background reduction the spectrograph must have very low instrumental backgrounds so that it remains sky noise limited. Both simulations and real world experience with the prototype GNOSIS system show that existing spectrographs, designed for higher sky background levels, will be unable to fully exploit the sky background reduction. We therefore propose PRAXIS, a spectrograph optimised specifically for this purpose. The PRAXIS concept is a fibre fed, fully cryogenic, fixed format spectrograph for the J and H-bands. Dark current will be minimised by using the best of the latest generation of NIR detectors while thermal backgrounds will be reduced by the use of a cryogenic fibre slit. Optimised spectral formats and the use of high throughput volume phase holographic gratings will further enhance sensitivity. Our proposal is for a modular system, incorporating exchangeable fore-optics units, integral field units and OH suppression units, to allow PRAXIS to operate as a visitor instrument on any large telescope and enable new developments in FBG OH suppression to be incorporated as they become available. As a high performance fibre fed spectrograph PRAXIS could also serve as a testbed for other astrophotonic technologies.
AB - Fibre Bragg grating (FBG) OH suppression is capable of greatly reducing the bright sky background seen by near infrared spectrographs. By filtering out the airglow emission lines at high resolution before the light enters the spectrograph this technique prevents scattering from the emission lines into interline regions, thereby reducing the background at all wavelengths. In order to take full advantage of this sky background reduction the spectrograph must have very low instrumental backgrounds so that it remains sky noise limited. Both simulations and real world experience with the prototype GNOSIS system show that existing spectrographs, designed for higher sky background levels, will be unable to fully exploit the sky background reduction. We therefore propose PRAXIS, a spectrograph optimised specifically for this purpose. The PRAXIS concept is a fibre fed, fully cryogenic, fixed format spectrograph for the J and H-bands. Dark current will be minimised by using the best of the latest generation of NIR detectors while thermal backgrounds will be reduced by the use of a cryogenic fibre slit. Optimised spectral formats and the use of high throughput volume phase holographic gratings will further enhance sensitivity. Our proposal is for a modular system, incorporating exchangeable fore-optics units, integral field units and OH suppression units, to allow PRAXIS to operate as a visitor instrument on any large telescope and enable new developments in FBG OH suppression to be incorporated as they become available. As a high performance fibre fed spectrograph PRAXIS could also serve as a testbed for other astrophotonic technologies.
KW - Fibre Bragg grating
KW - Infrared
KW - OH suppression
KW - Spectroscopy
UR - http://www.scopus.com/inward/record.url?scp=84871979977&partnerID=8YFLogxK
U2 - 10.1117/12.924874
DO - 10.1117/12.924874
M3 - Conference proceeding contribution
SN - 9780819491510
VL - 8450
SP - 84501V-1-84501V-6
BT - Modern Technologies in Space- and Ground-Based Telescopes and Instrumentation II
A2 - Navarro, Ramón
A2 - Cunningham, Colin R.
A2 - Prieto, Eric
PB - SPIE
CY - Bellingham, WA
ER -