Prototype Spectrometer 7.6 - 12.0 μm

The mid-infrared region from 6 μm to 12 µm (1667 cm ^-1 to 833 cm ^-1 ) is very interesting for many industrial and research applications because many molecules have defining absorption lines exactly there. Unfortunately, the detectors (typically HgCdTe) used in FTIR systems for spectroscopy purposes suffer from significant amounts of thermal noise due to their low bandgap. Hence, high levels of input light are needed with long exposure times to achieve a satisfactory signal-to-noise ratio. NLIR is pushing its technology to cover this extended wavelength region in the future. Currently, the prototype edition of the long-wavelength spectrometer covers 7.6 μm to 12.0 μm (1316 cm ^-1 to 833 cm ^-1 ).

The spectrometer is currently available with a 50 Hz full-spectrum readout rate and a resolution of 10 cm-1. The sensitivity is 200 pW/nm (-67 dBm/nm) with full aperture exposure.

The prototype spectrometer has a large free-space input, which makes it easy to couple in lots of light and ideal for reference measurements (e.g. in ATR crystals, gas cell, sample transmission/reflection, etc.) with a fixed light source. Due to the large input, the response of the spectrometer is, however, sensitive to the angle of input, which makes an input power calibration necessary for the characterization of light sources.