Quantum fisher information analysis for absorption measurements with undetected photons
Abstract
Abstract We theoretically compare the quantum Fisher information (QFI) for three configurations of absorption spectroscopy with undetected idler photons: an SU(1,1) interferometer with inter-source idler loss, an induced-coherence (IC) setup in which the idler partially seeds a second squeezer together with a vacuum ancilla, and a distributed-loss (DL) scheme with in-medium attenuation. We calculate the QFI as a function of parametric gain for both full and signal-only detection access. For losses below 99% and low to moderate gain, the SU(1,1) configuration provides the largest QFI. At high gain and intermediate loss, the IC scheme performs best, while under extreme attenuation (transmission < 1%) the DL model becomes optimal. These results delineate the measurement regimes in which each architecture is optimal in terms of information theory.
Fields of Study & Subjects
Quantum Information and Cryptography
Spectroscopy and Quantum Chemical Studies
Quantum optics and atomic interactions
Publication details
- Journal / source
- Journal of Physics Photonics
- Publisher
- IOP Publishing
- Volume
- 8
- Issue
- 3
- Pages
- 035013–035013
- Publication date
- 25 June 2026
- Language
- EN