Absorption spectroscopy by means of tunable lasers is a prime application for single mode VCSELs. Some real pioneer work was done here using VCSEL-based systems on the first industrial diode laser spectrometers, which were built in economically significant numbers.
Among its uses, optical measurement of oxygen has to be highlighted. This occurs at the band around 760 nm. In addition to this wavelength we also offer single mode VCSELs at 948 nm, which can be used for humidity measurement.
