Sub-shot-noise mid-infrared photothermal measurements using twin beams
Abstract
Mid-infrared photothermal (MIP) measurement probes refractive-index changes induced by mid-infrared (MIR) absorption using visible or near-infrared light and has recently emerged as a powerful modality for MIR spectro-imaging in the life sciences. Reducing measurement noise allows the probe power to be lowered without compromising the signal-to-noise ratio (SNR), thereby mitigating the risk of sample damage. However, even in the absence of classical noise, the SNR of conventional MIP measurements using a classical coherent probe is fundamentally limited by shot noise. Here, we demonstrate sub-shot-noise MIP measurement using twin beams generated through seeded optical parametric amplification. Balanced detection of the twin beams suppresses the noise by more than 5 dB below the shot-noise level established using a coherent beam. As a proof-of-principle demonstration, we measure the MIP signal from liquid water using balanced twin-beam detection and achieve an SNR enhancement of more than 2 dB over the balanced coherent-beam detection.
Related
- Shot-noise-limited few-cycle mid-infrared frequency comb with attosecond phase stability
- Physics-informed Kolmogorov-Arnold networks (PIKANs) for noise-robust reconstruction of boiling heat flux from infrared measurements
- Infrared Photothermal Heterodyne Imaging in Thermally Thick Medium for Thermo-optic Property Characterizations
- Deflection monitoring of discontinuous built-up beams using FBG measurements with mechanics-guided regularization
- Millimeter-scale wide-field mid-infrared photothermal imaging enabled by a broadly tunable picosecond optical parametric oscillator
BibTeX
@misc{hashimoto2026subshotnoise,
title = {{Sub-shot-noise mid-infrared photothermal measurements using twin beams}},
author = {Kazuki Hashimoto and Takuro Ideguchi},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.10294},
eprint = {2610.10294},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.10294},
}
RIS
TY - UNPB
TI - Sub-shot-noise mid-infrared photothermal measurements using twin beams
AU - Kazuki Hashimoto
AU - Takuro Ideguchi
PY - 2026
DA - 2026/10/07
PB - arXiv
DO - 10.48550/arxiv.2610.10294
UR - https://arxiv.org/abs/2610.10294
AB - Mid-infrared photothermal (MIP) measurement probes refractive-index changes induced by mid-infrared (MIR) absorption using visible or near-infrared light and has recently emerged as a powerful modality for MIR spectro-imaging in the life sciences. Reducing measurement noise allows the probe power to be lowered without compromising the signal-to-noise ratio (SNR), thereby mitigating the risk of sample damage. However, even in the absence of classical noise, the SNR of conventional MIP measurements using a classical coherent probe is fundamentally limited by shot noise. Here, we demonstrate sub-shot-noise MIP measurement using twin beams generated through seeded optical parametric amplification. Balanced detection of the twin beams suppresses the noise by more than 5 dB below the shot-noise level established using a coherent beam. As a proof-of-principle demonstration, we measure the MIP signal from liquid water using balanced twin-beam detection and achieve an SNR enhancement of more than 2 dB over the balanced coherent-beam detection.
ER -