Limits to Single Photon Detection: Amplification*

We have constructed a model of photo detection that is both idealized and realistic enough to calculate the limits and tradeoffs inherent to single photon detector (SPD) figures of merit. This model consists of three parts: transmission [1], amplification [2], and measurement. In this talk, we discuss the effects of signal amplification post-filtering; by first writing correct commutator-preserving transformations for non-linear photon-number amplification (e.g. avalanche photodiode, electron-hole pair creation, electron shelving), we derive alternative noise limits that out- perform the well-known Caves limits for linear amplification of bosonic mode amplitudes and possess no zero-temperature noise contribution to boson number SNR. We then discuss the optimistic implications for single photon detection. Lastly, we briefly discuss the pre-amplification filtering process (transmission) along with the construction of POVMs completely describing photo detectors (measurement), from which we can calculate all standard SPD figures of merit.
[1] Tz. B. Propp and S. J. van Enk, Phys. Rev. A 100, 033836 (2019).
[2] Tz. B. Propp and S. J. van Enk, Opt. Express 27, 23454 (2019).