CC BY-NC 4.0Kumar, MohitMohitKumarDupish, DupishDupishDupishKumar, PawanPawanKumarZhang, LuoshaLuoshaZhangLung, ShaunShaunLungBesaga, Vira R.Vira R.BesagaPertsch, ThomasThomasPertschSetzpfandt, FrankFrankSetzpfandt2025-11-122025-11-122025https://publica.fraunhofer.de/handle/publica/49913610.1063/5.029783710.24406/publica-62562-s2.0-105019494474Quantum nonlinear interferometers play an important role in quantum imaging and sensing applications. Here, we demonstrate the tailoring of the frequency-angular spectrum of such a device, where we use a linear dispersive medium as a phase corrector. By changing the thickness of the dispersive medium, we tune the phase of the interferometer, enabling control over the frequency-angular spectrum and visibility of the interference fringes. Utilizing the enhanced visibility achieved through our proposed technique, we show the application of a simple interferometer in spectroscopy with an undetected photon scheme. We distinguish different polymers by measuring their characteristic absorption features in the mid-infrared spectral range above 6 μm while detecting only photons in the visible range.enfalsejournal article