Near infrared throughput and stray light measurements of diffraction gratings for ELT-HARMONI

John I. Capone; Myriam Rodrigues; Fraser Clarke; Andrew Earle; Thomas Foster; Andrea Hidalgo Valadez; Ian Lewis; James Lynn; Kieran O'Brien; Matthias Tecza; Niranjan Thatte; Ian Tosh

doi:10.1117/12.2310086

24 September 2018 Near infrared throughput and stray light measurements of diffraction gratings for ELT-HARMONI

John I. Capone, Myriam Rodrigues, Fraser Clarke, Andrew Earle, Thomas Foster, Andrea Hidalgo Valadez, Ian Lewis, James Lynn, Kieran O'Brien, Matthias Tecza, Niranjan Thatte, Ian Tosh

Author Affiliations +

Proceedings Volume 10706, Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation III; 1070644 (2018) https://doi.org/10.1117/12.2310086
Event: SPIE Astronomical Telescopes + Instrumentation, 2018, Austin, Texas, United States

Abstract

The High Angular Resolution Monolithic Optical and Near-infrared Integral field spectrograph (HARMONI) will be one of the instruments installed on ESO's 39-meter Extremely Large Telescope (ELT) at first light. The instrument will operate from 0.47 - 2.45 μm with Δλ/λ = 3,000 - 17,000. On-sky spatial pixels (spaxels) are divided between four spectrographs, each equipped with 11 transmission diffraction gratings to cover the ranges of wavelengths and spectral resolutions. These spectrographs will be cooled to ~140 K to decrease thermal radiation at longer wavelengths.

In all configurations, the diffraction grating will lose a greater fraction of scientific light than any other single optic in the instrument. Additionally, manufacturers are often unable to measure the fraction of transmitted light at HARMONI's longest wavelengths. For these reasons, we have developed a setup to measure the efficiencies of transmission diffraction gratings across HARMONI's bandpass. The setup uses modulated signals, a single detector, and a lock-in amplifier to minimize sources of systematic errors. A modified version of this setup may be used to measure stray light. These setups and initial results are presented.

Citation Download Citation

John I. Capone, Myriam Rodrigues, Fraser Clarke, Andrew Earle, Thomas Foster, Andrea Hidalgo Valadez, Ian Lewis, James Lynn, Kieran O'Brien, Matthias Tecza, Niranjan Thatte, and Ian Tosh "Near infrared throughput and stray light measurements of diffraction gratings for ELT-HARMONI", Proc. SPIE 10706, Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation III, 1070644 (24 September 2018); https://doi.org/10.1117/12.2310086

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available

Members: $17.00

Non-members: $21.00 ADD TO CART

PROCEEDINGS
8 PAGES

DOWNLOAD PAPER SAVE TO MY LIBRARY

GET CITATION

RIGHTS & PERMISSIONS

Get copyright permission Get copyright permission on Copyright Marketplace

KEYWORDS

Diffraction gratings

Stray light

Sensors

Signal detection

Monochromators

Modulation

Optical testing

Show All Keywords

Keywords/Phrases

Search In:

Publication Years