title: Fourier transform spectroscopy in the vibrational fingerprint region with a birefringent interferometer.
abstract: We introduce a birefringent interferometer for Fourier transform (FT) spectroscopy in the mid-infrared, covering the vibrational fingerprint region (5-10 µm, 1000-2000 cm-1), which is crucial for molecular identification. Our interferometer employs the crystal calomel (Hg2Cl2), which combines high birefringence (ne-no≈0.55) with a broad transparency range (0.38-20 µm). We adopt a design based on birefringent wedges, which is simple and compact and guarantees excellent delay accuracy and long-term stability. We demonstrate FTIR spectroscopy, with a frequency resolution of 3 cm-1, as well as two-dimensional IR (2DIR) spectroscopy. Our setup can be extended to other spectroscopic modalities such as vibrational circular dichroism and step-scan FT spectroscopy.
authors.forename: J
authors.initials: J
authors.lastname: Réhault
authors.forename: R
authors.initials: R
authors.lastname: Borrego-Varillas
authors.forename: A
authors.initials: A
authors.lastname: Oriana
authors.forename: C
authors.initials: C
authors.lastname: Manzoni
authors.forename: C P
authors.initials: CP
authors.lastname: Hauri
authors.forename: J
authors.initials: J
authors.lastname: Helbing
authors.forename: G
authors.initials: G
authors.lastname: Cerullo