Fourier transform spectroscopy in the vibrational fingerprint region with a birefringent interferometer

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<sup>-1</sup>), which is crucial for molecular identification. Our interferometer employs the crystal calomel (Hg<sub>2</sub>Cl<sub>2</sub>), which combines high birefringence (n<sub>e</sub>-n<sub>o</sub>≈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<sup>-1</sup>, 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.


Published in:
Optics express, 25, 4, 4403-4413
Year:
2017
Publisher:
Washington, Optical Society of America
ISSN:
1094-4087
Laboratories:




 Record created 2017-04-17, last modified 2018-09-13


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