Realizing Integral Field Spectroscopy in the Far-Infrared

The optical design of an integral field spectrometer for far-infrared observations, the Far-Infrared Field-Imaging Line Spectrometer (FIFI LS), is presented. The instrument will fly on board the joint NASA/DLR airborne observatory SOFIA, observing in two nearly independent wavelength channels simultaneously: a blue channel (40-105 μm) and a red channel (105-210 μm). To achieve instantaneous integral field spectroscopy for the first time in the far-infrared, a novel reflective image slicer system is utilized that slices the 5 × 5 pixel, two-dimensional field of view into a pseudo-long slit of 25 × 1 pixels. The slicer assembly consists of three sets of five mirrors that have optical power, enabling a compact design. After the sky field has been optically rearranged to the pseudoslit, the image is spectrally dispersed in a standard Littrow-mounted reflective grating spectrometer. The practical concerns for the optical design in the far-infrared and, in particular, the significant effect of diffraction in the entire optical system is discussed.

[1]  Norbert Geis,et al.  The Photodetector Array Camera & Spectrometer (PACS) for the Herschel Space Observatory , 2003, SPIE Astronomical Telescopes + Instrumentation.

[2]  Göran Pilbratt,et al.  Herschel Space Observatory mission overview , 2003, SPIE Astronomical Telescopes + Instrumentation.

[3]  Rainer Hoenle,et al.  FIFI LS: a far-infared 3D spectral imager for SOFIA , 2003, SPIE Astronomical Telescopes + Instrumentation.

[4]  Rainer Hoenle,et al.  FIFI LS: the optical design and diffraction analysis , 2003, SPIE Astronomical Telescopes + Instrumentation.

[5]  Rainer Hoenle,et al.  Far-infrared photoconductors for Herschel and SOFIA , 2003, SPIE Astronomical Telescopes + Instrumentation.

[6]  R. Davies,et al.  The SAURON project – I. The panoramic integral-field spectrograph , 2001, astro-ph/0103451.

[7]  Frank Eisenhauer,et al.  SPIFFI image slicer: revival of image slicing with plane mirrors , 2000, Astronomical Telescopes and Instrumentation.

[8]  Norbert Geis,et al.  16 x 25 Ge:Ga detector arrays for FIFI LS , 2000, Astronomical Telescopes and Instrumentation.

[9]  W. Raab,et al.  Realizing 3D spectral imaging in the far-infrared: FIFI LS , 2000, Astronomical Telescopes and Instrumentation.

[10]  Roger Haynes,et al.  Multiple‐Object and Integral Field Near‐Infrared Spectroscopy Using Fibers , 1999 .

[11]  Guenther Kettenring,et al.  FIFI LS: a field-imaging far-infrared line spectrometer for SOFIA , 1998, Astronomical Telescopes and Instrumentation.

[12]  Erick T. Young,et al.  Multiband imaging photometer for SIRTF , 1998, Astronomical Telescopes and Instrumentation.

[13]  Roger Haynes,et al.  Integral field spectroscopy with the GEMINI multiobject spectrographs , 1997, Other Conferences.

[14]  N. Thatte,et al.  3D: The next generation near-infrared imaging spectrometer , 1996 .

[15]  Leonid I. Goray.  Rigorous integral method in application to computing diffraction on relief gratings working in wavelength range from microwaves to x ray , 1995, Optics & Photonics.

[16]  N. Geis,et al.  The MPE/UCB far-infrared imaging Fabry-Perot interferometer (FIFI) , 1990 .

[17]  David Stanley Evans,et al.  Instrumentation for astronomy with large optical telescopes , 1983 .

[18]  Colin M. Humphries.  Instrumentation for astronomy with large optical telescopes , 1982 .

[19]  Colin M. Humphries.  Instrumentation for astronomy with large optical telescopes : proceedings of IAU colloquium no. 67, held at Zelenchukskaya, U.S.S.R., 8-10 September, 1981 , 1982 .

[20]  G. Courtes.  An Integral Field Spectrograph (IFS) for Large Telescopes , 1982 .

[21]  C. Vanderriest.  A FIBER-OPTICS DISSECTOR FOR SPECTROSCOPY OF NEBULOSITIES AROUND QUASARS AND SIMILAR OBJECTS , 1980 .

[22]  W. R. Smythe.  The Double Current Sheet in Diffraction , 1947 .