While mainly used for infrared spectroscopy, our FTIR spectrometers can also be used for emission measurement to characterize lasers or other types of light sources (thermal sources, LED). Our instruments can also be calibrated to perform radiometric measurements, provided that the end user has access to a calibrated light source.
For emission measurements, Arcoptix offers a NIR and MIR spectrometer without built-in light source. While most light sources can readily be characterized with our FTIR, special care must be given to pulsed sources, typically lasers. Since the FTIR acts as a modulator, spurious artifacts might show up in the spectrum if the repetition rate of the source falls within the modulation bandwidth of the instrument. Therefore, only pulsed sources with repetition rates above 25 kHz can be measured accurately using either our FTNIR or FTMIR. On request, our MIR FTIR can also be aligned to measure at a resolution of 0.5cm-1 to distinguish fine features in narrow band sources.
FTMIR-L1-120-4TE free-space input and its removable fiber couplerNotice that our spectrometers are not irradiance calibrated. A approximative calibration can be made with the help of a blackbody with a known spectrum.
In order to efficiently alternate between free-space and fiber coupled transmission, Arcoptix offers two types of optical fiber couplers that are matched to the optics of our FTIR spectrometers. Lensed couplers are usually preferred for NIR sources, while reflective couplers are required for MIR radiation beyond ~6µm.
Parabolic reflector coupler
Lensed coupler