Volume phase holographic (VPH) grisms for infrared and optical spectrographs

Hill, Gary J.; Wolf, Marsha J.; Tufts, Joseph R.; Smith, Erin C.

doi:10.1117/12.458103

Cited by 21 publications

(8 citation statements)

References 11 publications

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“…We used a matched filter based on the algorithm of Postman et al 25 to select cluster candidates likely to be at z ~ 0.25, and culled these candidates by eye due to the coarse plate scale of the images and low galactic latitude (b ~ 20 o ). Redshifts of 15 of these cluster candidates have been obtained with the HET LRS in multi-object mode, or with the Imaging Grism Instrument 26 degree area of the superstructure the RS differs from that expected for NVSS 20 at 99.8% confidence. Three clusters are also associated with the second structure, so 3/4 of the clusters are in large structures traced by the RS.…”

Section: Further Observationsmentioning

confidence: 99%

TOOT survey and the largest structure in the universe

Hill

Tufts

Bergmann

et al. 2003

Discoveries and Research Prospects From 6- To 10-Meter-Class Telescopes II

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The Texas-Oxford One Thousand (TOOT) radio source redshift survey is aimed at understanding the evolution of the radio source population down to flux density of S 151MHz = 100 mJy. This low frequency survey has a depth equivalent to about five times the NVSS limit, but does not contain the population of star forming galaxies detected in the NVSS survey. In addition, the survey reaches a high enough surface density of sources on the sky to probe large-scale structure at z ~ 1. Radio sources inhabit massive elliptical galaxies, and as such provide excellent sparse tracers of large-scale structure that are both easily identified and easily observed with spectrographs to map out their space distribution. We review the properties of the TOOT survey and its current status.We also report the discovery, using radio sources, of a huge structure at z=0.27 traced by radio sources and galaxy clusters. Such superstructures are aggregates of clusters seeded by rare (> 3σ) peaks in the power spectrum at recombination. The radio sources and galaxy clusters are shown to trace the same matter distribution. This is the first demonstration of radio AGN as direct sparse tracers of the underlying dark matter distribution. The extent of the superstructure is of order 100 h -1 Mpc in three dimensions, making it the largest structure known, and indicating a mass similar to that of the Great Attractor. We report the properties of the superstructure, and consider the implications of its existence.

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Section: Further Observationsmentioning

confidence: 99%

TOOT survey and the largest structure in the universe

Hill

Tufts

Bergmann

et al. 2003

Discoveries and Research Prospects From 6- To 10-Meter-Class Telescopes II

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“…Our extensive experience with the VPH-based dispersing elements has shown that meeting the lower limit of this requirement is possible. [39][40][41] As can be seen in Fig. 7, the grisms have a square footprint with 150 mm sides to ease their mounting in the instrument (see the following section).…”

Section: Vph Grismsmentioning

confidence: 99%

Design and construction progress of LRS2-B: a new low resolution integral-field spectrograph for the Hobby-Eberly Telescope

et al. 2012

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Note from the author (July 25, 2014): this paper has been superseded by Ref. 1 (arXiv:1407.6016).The upcoming Wide-Field Upgrade (WFU) has ushered in a new era of instrumentation for the Hobby-Eberly Telescope (HET). Here, we present the design, construction progress, and lab tests completed to date of the blue-optimized second generation Low Resolution Spectrograph (LRS2-B). LRS2-B is a dual-channel, fiber fed instrument that is based on the design of the Visible Integral Field Replicable Unit Spectrograph (VIRUS), which is the new flagship instrument for carrying out the HET Dark Energy eXperiment (HETDEX). LRS2-B utilizes a microlens-coupled integral field unit (IFU) that covers a 7 ×12 area on the sky having unity fill-factor with ∼300 spatial elements that subsample the median HET image quality. The fiber feed assembly includes an optimized dichroic beam splitter that allows LRS2-B to simultaneously observe 370 < λ(nm) < 470 and 460 < λ(nm) < 700 at fixed resolving powers of R ≈ λ/∆λ ≈ 1900 and 1200, respectively. We discuss the departures from the nominal VIRUS design, which includes the IFU, fiber feed, camera correcting optics, and volume phase holographic grisms. Additionally, the motivation for the selection of the wavelength coverage and spectral resolution of the two channels is briefly discussed. One such motivation is the follow-up study of spectrally and (or) spatially resolved Lyα emission from z ≈ 2.5 star-forming galaxies in the HETDEX survey. LRS2-B is planned to be a commissioning instrument for the HET WFU and should be on-sky during quarter 4 of 2013. Finally, we mention the current state of LRS2-R, the red optimized sister instrument of LRS2-B. LRS2-B as a Facility InstrumentAs a replacement for LRS and as a second generation facility instrument, LRS2 must enable all of the ongoing LRS science and provide new science opportunities for the HET community. Such general use capabilities are a ‡ We have assumed Schott N-BK7HT internal transmittance: http://edit.schott.com/advanced optics/us/abbe datasheets/schott datasheet n-bk7ht.pdf

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“…5 Each of the two custom VPHGs is photographically produced on a thin gelatin layer sandwiched between two 5 mm BK7 flats. The gelatin thickness (determined by the manufacturer, Wasatch Photonics) and line frequency are the critical parameters for determining wavelength range, and blaze angle (Bragg angle).…”

Section: Vph Gratingsmentioning

confidence: 99%

LRS-J: instrument design and characterization

et al. 2004

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LRS-J is a 142 mm f / 1 near infrared (J-Band) camera designed as a drop in replacement for the optical camera installed on the Hobby-Eberly Telescope (HET) multi-object low resolution spectrograph (LRS). The Hawaii-1RG (H1RG) based instrument is liquid nitrogen cooled, but it mates to the warm LRS making use of the existing longslit and multi-object (MOS) units as well as the existing optical collimator. LRS-J utilizes a molecular beam epitaxy (MBE) based Hawaii-1RG (H1RG) detector. The design is a fully cryogenic catadioptric Maksutov-type, with the detector at the internal focus. This configuration produces excellent images, but presents particular challenges in the mounting of the detector. This is the first time that such an arrangement has been used in an astronomical instrument with an infrared detector. By replacing the conventional optical grisms with two 170 mm diameter near-IR VPH grisms, LRS-J covers the 0.9-1.3 µm bandpass with R ~ 1750-2000.We present the opto-mechanical design of LRS-J including the thermally self-compensating corrector doublet mount, and 100 µm/turn cryogenic mirror adjusters, FEA optimized vacuum housing, and custom Dewar. We also characterize the electrical and thermal connections necessary to mount the detector head in this unusually small inverted arrangement.

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Volume phase holographic (VPH) grisms for infrared and optical spectrographs

Cited by 21 publications

References 11 publications

TOOT survey and the largest structure in the universe

TOOT survey and the largest structure in the universe

Design and construction progress of LRS2-B: a new low resolution integral-field spectrograph for the Hobby-Eberly Telescope

LRS-J: instrument design and characterization

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