Off-axis re-entrant cavity ring-down spectroscopy with a mid-infrared continuous-wave optical parametric oscillator
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- Peltola, J., Vainio, M., Ulvila, V. et al. Appl. Phys. B (2012) 107: 839. doi:10.1007/s00340-012-5074-x
We demonstrate an off-axis cavity ring-down spectroscopy system, which uses a mid-infrared continuous-wave optical parametric oscillator as a light source. Off-axis injection with re-entrant configuration of the ring-down cavity is used to achieve high spectral resolution while maintaining high measurement speed. This makes the setup suitable for sensitive molecular spectroscopy in the mid-infrared region, particularly for studies that require high temporal resolution. Formaldehyde (H2CO) absorption spectrum at 3.4 µm is measured using the off-axis re-entrant cavity ring-down spectrometer.