We have demonstrated sensing of formaldehyde (H_2CO) using a room-temperature distributed feedback interband cascade laser (ICL) emitting around 3493 nm. The ICL has been characterized and proved to be very suitable for tunable laser spectroscopy (TLS). The H_2CO TLS spectra were recorded in direct absorption mode and showed excellent agreement with the Pacific Northwest National Laboratory database. The measurements reported here were taken from a series of measurements of a mixture of H_2CO in air obtained by vaporizing a solution also containing methanol and formic acid. We obtained a resolution limit better than 1 ppm × m assuming a relative absorption of 10~(-3).
展开▼
