First light demonstration of the integrated superconducting spectrometer

Ultra-wideband 3D imaging spectrometry in the millimeter-submillimeter (mm-submm) band is an essential tool for uncovering the dust-enshrouded portion of the cosmic history of star formation and galaxy evolution. However, it is challenging to scale up conventional coherent heterodyne receivers or free-space diffraction techniques to sufficient bandwidths ($\geq$1 octave) and numbers of spatial pixels (>$10^2$). Here we present the design and first astronomical spectra of an intrinsically scalable, integrated superconducting spectrometer, which covers 332-377 GHz with a spectral resolution of $F/\Delta F \sim 380$. It combines the multiplexing advantage of microwave kinetic inductance detectors (MKIDs) with planar superconducting filters for dispersing the signal in a single, small superconducting integrated circuit. We demonstrate the two key applications for an instrument of this type: as an efficient redshift machine, and as a fast multi-line spectral mapper of extended areas. The line detection sensitivity is in excellent agreement with the instrument design and laboratory performance, reaching the atmospheric foreground photon noise limit on sky. The design can be scaled to bandwidths in excess of an octave, spectral resolution up to a few thousand and frequencies up to $\sim$1.1 THz. The miniature chip footprint of a few $\mathrm{cm^2}$ allows for compact multi-pixel spectral imagers, which would enable spectroscopic direct imaging and large volume spectroscopic surveys that are several orders of magnitude faster than what is currently possible.Comment: Published in Nature Astronomy. SharedIt Link to the full published paper: https://rdcu.be/bM2F

Quasi-optical system for the DESHIMA spectrometer

DESHIMA is a superconducting on-chip spectrometer using MKIDs in the sub-mm wavelength regime (240-720 GHz, 1:3 bandwidth). This thesis presents (1) an analysis of the quasi-optical system used for DESHIMA on the ASTE telescope in Chile (2) design of the room-temperature optics of this design and (3) a preliminary investigation into an ultra-wideband leaky-lens antenna suitable for multi-pixel, constant aperture efficiency operation to be used as a feed to high f-number (>2) reflectors. The designed and analyzed optics show good performance and tolerance for the fall 2017 campaign of DESHIMA-on-ASTE. The wideband investigation leads to constant, >70% optical efficiency over the 1:3 bandwidth for a single pixel design (f-num=3.7) or >55% optical efficiency with multiple pixels spaced at 2*\lambda*f-number (f-num=5). Future work must be done to optimize the radiation efficiency of the antenna over the whole bandwidth, which is now the largest obstacle to frequency-dispersion free aperture efficiency.DESHIMAElectrical Engineerin

Detection of circulating breast tumor cells by differential expression of marker genes

Purpose: We undertook a systematic approach to identify breast cancer (BC) marker genes with molecular assays and evaluated these marker genes for the detection of minimal residual disease in peripheral blood mononuclear cells (PBMCs). Experimental Design: We used serial analysis of gene expression to identify a range of genes that were expressed in BC but absent in the expression profiles of blood and bone marrow cells. Next, we evaluated a panel of four marker genes (p1B, PS2, CK19, and EGP2) by real-time quantitative PCR in 103 PBMC samples from patients with metastatic BC (stage III/IV) and in 96 PBMC samples from healthy females. Results: Increased marker gene expression of at least one marker was seen in 33 of 103 patients. Using quadratic discriminant analysis including all four marker genes, we determined a discriminant value with 29% positivity in the BC patient group that did not yield false positive results among the healthy females. Conclusions: Real-time PCR for the simultaneous expression of multiple cancer-specific genes may ensure the specificity required for the clinical application of mRNA expression-based assays for occult tumor cell