16:1 bandwidth two-layer antireflection structure for silicon matched to the 190–310  GHz atmospheric window

Defrance, Fabien; Jung-Kubiak, Cecile; Sayers, Jack; Connors, J.; deYoung, Clare; Hollister, Matthew I.; Yoshida, Hiroshige; Chattopadhyay, Goutam; Golwala, S. R.; Radford, Simon J. E.

doi:10.1364/ao.57.005196

Cited by 27 publications

(10 citation statements)

References 34 publications

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“…DRIE is used to etch each wafer 23 , from both sides (so we will only need to etch 250 µm deep holes). We have already successfully achieved DRIE patterning and bonding of silicon wafers to create an antireflection treatment with subwavelength structures 12 . We are applying the same technique to fabricate the GRIN lens.…”

Section: Fabrication Methodsmentioning

confidence: 99%

Flat Low-Loss Silicon Gradient Index Lens for Millimeter and Submillimeter Wavelengths

et al. 2019

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We present the design, simulation, and planned fabrication process of a flat high resistivity silicon gradient index (GRIN) lens for millimeter and submillimeter wavelengths with very low absorption losses. The gradient index is created by subwavelength holes whose size increases with the radius of the lens. The effective refractive index created by the subwavelength holes is constant over a very wide bandwidth, allowing the fabrication of achromatic lenses up to submillimeter wavelengths. The designed GRIN lens was successfully simulated and shows an expected efficiency better than that of a classic silicon plano-concave spherical lens with approximately the same thickness and focal length. Deep reactive ion etching (DRIE) and wafer-bonding of several patterned wafers will be used to realise our first GRIN lens prototype.Many applications in astronomy from tens of GHz to THz frequencies, such as CMB polarization studies and Sunyaev-Zeldovich effect observations, would benefit from low loss and wide bandwidth optics. High resistivity silicon (HRSi) is an excellent material for optics within this frequency range because of its high refractive index (n Si = 3.42 1,2 ), achromaticity, lack of birefringence, low loss 3 , high thermal conductivity, and strength. Silicon's high index, however, presents a challenge for antireflection (AR) treatment, which our approach addresses. To develop wide bandwidth and low loss silicon optics, we are focusing on two key elements: 1) the fabrication of multilayer AR structures via multi-depth deep reactive ion etching (DRIE) and wafer-bonding; and 2) the assembly of gradient index (GRIN) optics, flat-faced to be consistent with AR treatment, by bonding multiple silicon wafers patterned with the desired radial index profile by DRIE. The fabrication of 1-layer 7,8,9,10,11 and 2layer 7,12 AR structures for THz frequencies has already been demonstrated, such as wafer bonding of unpatterned 13,14,15,7 and patterned 16 silicon wafers. Prior attempts to fabricate GRIN lenses for millimeter and submillimeter wavelengths, using silicon and DRIE 17,18,19 ,

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Section: Fabrication Methodsmentioning

confidence: 99%

Flat Low-Loss Silicon Gradient Index Lens for Millimeter and Submillimeter Wavelengths

et al. 2019

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“…For minimal absorption by the substrates, the arrays should be fabricated with silicon for wavelengths greater than 20 µm and germanium for 10 -20 µm because of the silicon absorption features in the 14 − 16 µm range. Microlens arrays could either be fabricated separately and bonded to back-illuminated KID arrays 64 or etched into the wafer frontside before or after KID fabrication. There are examples of silicon microlens fabrication in the literature that could achieve the micron-level tolerances required for operation down to 10 µm, [65][66][67][68][69][70][71] although those involving micromachining and laser etching would likely be too slow for arrays of 10 4 detectors.…”

Section: Kinetic Inductance Detectors and Readout Electronicsmentioning

confidence: 99%

Galaxy Evolution Probe

Glenn

Bradford

Rosolowsky

et al. 2021

J. Astron. Telesc. Instrum. Syst.

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The Galaxy Evolution Probe (GEP) is a concept for a mid-and far-infrared space observatory to measure key properties of large samples of galaxies with large and unbiased surveys. GEP will attempt to achieve zodiacal light and Galactic dust emission photon backgroundlimited observations by utilizing a 6-K, 2.0-m primary mirror and sensitive arrays of kinetic inductance detectors (KIDs). It will have two instrument modules: a 10 to 400 μm hyperspectral imager with spectral resolution R ¼ λ∕Δλ ≥ 8 (GEP-I) and a 24 to 193 μm, R ¼ 200 grating spectrometer (GEP-S). GEP-I surveys will identify star-forming galaxies via their thermal dust emission and simultaneously measure redshifts using polycyclic aromatic hydrocarbon emission lines. Galaxy luminosities derived from star formation and nuclear supermassive black hole accretion will be measured for each source, enabling the cosmic star formation history to be measured to much greater precision than previously possible. Using optically thin far-infrared fine-structure lines, surveys with GEP-S will measure the growth of metallicity in the hearts of galaxies over cosmic time and extraplanar gas will be mapped in spiral galaxies in the local universe to investigate feedback processes. The science case and mission architecture designed to meet the science requirements is described, and the KID and readout electronics state of the art and needed developments are described. This paper supersedes the GEP concept study report cited in it by providing new content, including: a summary of recent mid-infrared KID development, a discussion of microlens array fabrication for mid-infrared KIDs, and additional context for galaxy surveys. The reader interested in more technical details may want to consult the concept study report. © The Authors. Published by SPIE under a Creative Commons Attribution 4.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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“…In calculation we assumed an 244 µm-thick anti-reflection (AR) layer with a dielectric constant of 4.5 and a backshort placed 517 µm away from the AR layer. This AR layer could be realized by an machined sub-wavelength structure on Si [15,16].…”

Section: Antenna and Feed Network Designmentioning

confidence: 99%

A kinetic inductance detectors array design for high background conditions at 150 GHz

Shu,

Sayers,

Day

2021

Preprint

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We present a design for an array of kinetic inductance detectors (KIDs) integrated with phased array antennas for imaging at 150 GHz under high background conditions. The microstrip geometry KID detectors are projected to achieve photon noise limited sensitivity with larger than 100 pW absorbed optical power. Both the microstrip KIDs and the antenna feed network make use of a low-loss amorphous silicon dielectric. A new aspect of the antenna implementation is the use of a NbTiN microstrip feed network to facilitate impedance matching to the 50 Ohm antenna. The array has 256 pixels on a 6-inch wafer and each pixel has two polarizations with two Al KIDs. The KIDs are designed with a half wavelength microstrip transmission line with parallel plate capacitors at the two ends. The resonance frequency range is 400 to 800 MHz. The readout feedline is also implemented in microstrip and has an impedance transformer from 50 Ohm to 9 Ohm at its input and output.

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16:1 bandwidth two-layer antireflection structure for silicon matched to the 190–310 GHz atmospheric window

Cited by 27 publications

References 34 publications

Flat Low-Loss Silicon Gradient Index Lens for Millimeter and Submillimeter Wavelengths

Flat Low-Loss Silicon Gradient Index Lens for Millimeter and Submillimeter Wavelengths

Galaxy Evolution Probe

A kinetic inductance detectors array design for high background conditions at 150 GHz

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