Low-coherence interferometry with undetected mid-infrared photons in the high-gain regime

2025/09/03 by Zotti, Giovanni, Horoshko, Dmitri B., Kolobov, Mikhail I. +4
#FOS: Physical sciences #Instrumentation and Detectors (physics.ins-det) #Optics (physics.optics) #Quantum Physics (quant-ph)

paper · doi:10.48550/arxiv.2509.03349

Abstract

We develop a high-parametric-gain SU(1,1) interferometer based on an aperiodically poled Potassium Titanyl Phosphate (apKTP) crystal, enabling frequency-domain low-coherence interferometry with undetected mid-infrared photons. The system achieves a signal-to-noise ratio as high as 40 dB and axial resolution of 30 μm, with a 3 μm-centered idler beam. By increasing the poling-period range, we also improve the axial resolution to 17 μm, demonstrating a straightforward route to enhance the performance by working on the crystal design

Citations

• Broadband spectroscopy and interferometry with undetected photons at strong parametric amplification
• Frequency-domain optical coherence tomography with undetected mid-infrared photons
• Super-bunched bright squeezed vacuum state

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