High efficiency half-wave plates for submillimetre polarimetry

Murray, Alexander; Flett, A. M.; Murray, Graham J.

doi:10.1016/0020-0891(92)90002-b

Cited by 22 publications

(13 citation statements)

References 13 publications

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“…More specifically, in the field of experimental cosmology, the detection of the polarisation of the Cosmic Microwave Background radiation (CMB) requires extremely sensitive broadband instruments with very low-loss and low cross-polarisation HWPs in front of these instruments. In the past these devices were realised using combinations of birefringent plates following the well-known Pancharatnam recipes [5][6][7][8]. However, nowadays CMB experiments aiming to the detection of the very faint polarisation B-modes require very large arrays and modulating devices with diameters that cannot be achieved using commercially available birefringent materials.…”

Section: Introductionmentioning

confidence: 99%

A Broadband Metal-Mesh Half-Wave Plate for Millimetre Wave Linear Polarisation Rotation

Pisano¹,

Ng²,

Haynes³

et al. 2012

PIER M

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Abstract-We present a polarisation rotator based on a dielectrically embedded metal Mesh Half Wave Plate (MHWP) working in the Wband frequency range (75-110 GHz). The device was realised using metallic grids with sub-wavelength anisotropic geometries able to mimic the behaviour of natural birefringent materials. The device was designed using a combination of transmission line codes and finiteelement analysis able to achieve phase accuracy down to a fraction of degree. Very accurate intensity and phase measurements were carried out using coherent radiation from a Vector Network Analyser (VNA). The presented device performs better and it is much thinner than previous devices having reduced the number of grids by a factor two and minimised their inductive losses. The new mesh HWP has excellent performances in terms of differential phase-shift flatness and cross-polarisation respectively 180.4 ± 2.9 • and −28 dB across a 25% bandwidth.

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Section: Introductionmentioning

confidence: 99%

A Broadband Metal-Mesh Half-Wave Plate for Millimetre Wave Linear Polarisation Rotation

Pisano¹,

Ng²,

Haynes³

et al. 2012

PIER M

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“…The polarization calibration sources were Jupiter and Uranus, assumed to be unpolarized. The polarization efficiency is 0.95, and a correction was applied for this e †ect (Murray et al 1992).…”

Section: Jcmt Observationsmentioning

confidence: 99%

Magnetic Orientations and Energetics in Interstellar Clumps within Small Clouds

Vallée

Bastien

2000

ApJ

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“…The biggest inefficiency comes from the HWP, which has 5-10 % absorption due to the half-wave plate 25 and another 2% loss due to imperfections in the a/r coatings.…”

Section: Throughputmentioning

confidence: 99%

SHARP: the SHARC-II polarimeter for CSO

Li¹,

Attard

Dowell

et al. 2006

SPIE Proceedings

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SHARC-II is a 32 x 12 pixel submillimeter camera that is used with the ten-meter diameter Caltech Submillimeter Observatory (CSO) on Mauna Kea. This camera can be operated at either 350 or 450 microns. We developed a module that is installed at the CSO Nasmyth focus in order to convert SHARC-II into a sensitive imaging polarimeter, which we refer to as "SHARP". SHARP splits the incident beam into two orthogonally polarized beams that are then re-imaged onto different halves of the SHARC-II bolometer array. When this removable polarimetry module is in use, SHARC-II becomes a dual-beam 12 x 12 pixel polarimeter. Sky noise is a significant source of error for submillimeter continuum observations. Because SHARP simultaneously observes two orthogonal polarization components, we are able to eliminate or greatly reduce this source of error. Here we describe the design of SHARP and report preliminary results of tests and observations carried out during our first two runs at CSO

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High efficiency half-wave plates for submillimetre polarimetry

Cited by 22 publications

References 13 publications

A Broadband Metal-Mesh Half-Wave Plate for Millimetre Wave Linear Polarisation Rotation

A Broadband Metal-Mesh Half-Wave Plate for Millimetre Wave Linear Polarisation Rotation

Magnetic Orientations and Energetics in Interstellar Clumps within Small Clouds

SHARP: the SHARC-II polarimeter for CSO

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