Quantum-limited discrimination of laser light and thermal light

Jonathan L. Habif, Arunkumar Jagannathan, Samuel Gartenstein, Phoebe Amory, Saikat Guha

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


Understanding the fundamental sensitivity limit of an optical sensor requires a full quantum mechanical description of the sensing task. In this work, we calculate the fundamental (quantum) limit for discriminating between pure laser light and thermal noise in a photon-starved regime. The Helstrom bound for discrimination error probability for single mode measurement is computed along with error probability bounds for direct detection, coherent homodyne detection and the Kennedy receiver. A generalized Kennedy (GK) receiver is shown to closely approach the Helstrom limit. We present an experimental demonstration of this sensing task and demonstrate a 15.4 dB improvement in discrimination sensitivity over direct detection using a GK receiver and an improvement of 19.4% in error probability over coherent detection.

Original languageEnglish (US)
Pages (from-to)7418-7427
Number of pages10
JournalOptics Express
Issue number5
StatePublished - Mar 1 2021

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics


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