School of Physics - Research Publications
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ItemThe Simons Observatory: The Large Aperture Telescope Receiver (LATR) integration and validation results(SPIE, 2020-01-01)The Simons Observatory (SO) will observe the cosmic microwave background (CMB) from Cerro Toco in the Atacama Desert of Chile. The observatory consists of three 0.5m Small Aperture Telescopes (SATs) and one 6m Large Aperture Telescope (LAT), covering six frequency bands centering around 30, 40, 90, 150, 230, and 280 GHz. The SO observations will transform our understanding of our universe by characterizing the properties of the early universe, measuring the number of relativistic species and the mass of neutrinos, improving our understanding of galaxy evolution, and constraining the properties of cosmic reionization.1 As a critical instrument, the Large Aperture Telescope Receiver (LATR) is designed to cool ∼60,000 transition-edge sensors (TES)2 to <100mK on a 1.7m diameter focal plane. The unprecedented scale of the LATR drives a complex design.3-5 In this paper, We will first provide an overview of the LATR design. Integration and validation of the LATR design is discussed in detail, including mechanical strength, optical alignment, and cryogenic performance of the five cryogenic stages (80 K, 40 K, 4 K, 1 K, and 100 mK). We will also discuss the microwave-multiplexing (μMux) readout system implemented in the LATR and demonstrate operation of dark, prototype TES bolometers. The μMux readout technology enables one coaxial loop to read out Ο(103) TES detectors. Its implementation within the LATR serves as a critical validation for the complex RF chain design. The successful validation of the LATR performance is not only a critical milestone within the Simons Observatory, it also provides a valuable reference for other experiments, e.g. CCAT-prime6 and CMB-S4.7, 8
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ItemNo Preview AvailableSimons Observatory Small Aperture Telescope overview(SPIE, 2020-01-01)The Simons Observatory (SO) will be a cosmic microwave background (CMB) survey experiment with three small-aperture telescopes (SATs) and one large-aperture telescope (LAT), which will observe from the Atacama Desert in Chile. In total, SO will field over 60,000 transition-edge sensor (TES) bolometers in six spectral bands centered between 27 and 280 GHz in order to achieve the sensitivity necessary to measure or constrain numerous cosmological quantities. The SATs are optimized for a primordial gravitational wave signal in a parity odd polarization power spectrum at a large angular scale. We will present the latest status of the SAT development.
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ItemSearches for heavy particles with leptons at ATLAS(Sissa Medialab, 2021-02-22)
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ItemAlgorithmic Spectral Reconstruction Using Angularly Tuned Zero-Contrast Gratings(IEEE, 2020)We experimentally demonstrate the algorithmic reconstruction of the infrared transmission spectrum of a polymer using a zero-contrast waveguide-grating metasurface as a filter. By changing the metasurface angle, a variety of filter functions are obtained.
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ItemGeometric Phase Metasurface Hologram for Optical Tractor Beam Generation(OSA & IEEE, 2020-01-01)We present a geometric phase silicon metasurface hologram design intended to produce a non-diffracting solenoid beam. Such optical beams have been shown to exert long range retrograde (i.e. toward source) optical forces on light-scattering particles.
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ItemLong -Wave In a ed Photodetectors Based on Platinum Diselenide(IEEE, 2020)We demonstrate long wave infrared photodetectors based on the transition metal dichalcogenide platinum diselenide (PtSe2) in its bulk form for the first time to our knowledge. Fabricated devices show sub-millisecond response times.
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ItemPolarization State Generation and Detection by VCSELs with Integrated Metasurfaces(OSA & IEEE, 2020-01-01)We experimentally demonstrate vertical-cavity surface-emitting lasers (VCSEL) with integrated plasmonic and dielectric metasurfaces. The metasurfaces shape the polarization of the laser emission from the VCSELs and also enable them to serve as polarization-dependent photodetectors.
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ItemSmartphone-based Optical Fiber Speckle Spectrometer(IEEE, 2020)We demonstrate a spectrometer that uses a smaityhone to image the speckle pattern produced by a multimode optical fiber. A smarjihone-based algorithm uses the measured pattern and a calibration library to determine the input spectnrm.
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ItemVisible to Long-Wave Infrared Photodetectors based on Copper Tetracyanoquinodimethane (CuTCNQ) Crystals(OSA - Optical Society of America, 2020-08-01)We demonstrate room-temperature photodetectors at wavelengths from visible (450 nm, 532 nm) to near- (850 nm), short-wave (1550 nm), mid-wave (4.5 \mu m) and long-wave (8.35 \mu m) infrared. These are based on drop-cast Cu TCNQ crystals.
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ItemMaterial identification with a filter array-detector array infrared microspectrometer: Numerical study(Optica Publishing Group, 2020-09-14)We design a plasmonic filter array for a filter array-detector array microspectrometer. We perform numerical experiments, including noise, that predict that this configuration would enable the identification of various materials via their infrared fingerprints.