Photon noise correlations in millimeter-wave telescopes

Many modern millimeter and submillimeter ("mm -wave") telescopes for astronomy are deploying more detectors by increasing the detector pixel density and, with the rise of lithographed detector architectures and highthroughput readout techniques, it is becoming increasingly practical to overfill the focal plane. However, when the pixel pitch ppix is small compared to the product of the wavelength lambda and the focal ratio F, or ppix <= 1.2 F lambda, the Bose term of the photon noise correlates between neighboring detector pixels due to the Hanbury Brown and Twiss (HBT) effect. When this HBT effect is non -negligible, the array -averaged sensitivity scales with the detector count Ndet less favorably than the uncorrelated limit of N-1/2 det . 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 a focal plane design. (c) 2024 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement