Nonlinear interferometry based on nondegenerate spontaneous parametric down-conversion allows for midinfrared spectroscopy without detecting mid-infrared photons. The authors develop Fourier-transform infrared spectroscopy with undetected photons using a high-parametric-gain nonlinear interferometer and demonstrate mid-infrared absorption spectroscopy of polymers.
- Kazuki Hashimoto
- Dmitri B. Horoshko
- Maria V. Chekhova
