Photon noise correlations in millimeter-wave telescopes

Abstract

Many modern millimeter and submillimeter (``mm-wave'') telescopes for astronomy are deploying more detectors by increasing detector pixel density, and with the rise of lithographed detector architectures and high-throughput readout techniques, it is becoming increasingly practical to overfill the focal plane. However, when the pixel pitch $p_{\mathrm{pix}}$ is small compared to the product of the wavelength $\lambda$ and the focal ratio $F$, or $p_{\mathrm{pix}}\lesssim 1.2F\lambda$, the Bose term of the photon noise correlates between neighboring detector pixels due to the Hanbury Brown & Twiss (HBT) effect. When this HBT effect is non-negligible, the array-averaged sensitivity scales with detector count $N_{\det }$ less favorably than the uncorrelated limit of $N_{\det }^{-1/2}$. In this paper, we present a general prescription to calculate this HBT correlation based on a quantum optics formalism and extend it to polarization-sensitive detectors. We then estimate the impact of HBT correlations on the sensitivity of a model mm-wave telescope and discuss the implications for focal-plane design.

arXiv comment24 pages, 16 figures

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Cited by in corpus (2)

• The Simons Observatory: A fully remote controlled calibration system with a sparse wire grid for cosmic microwave background telescopes
• Measurement and Modeling of Polarized Atmosphere at the South Pole with SPT-3G