Diagnostics of ortho and para water isomers with tunable diode lasers

A spectrometer based on tunable diode lasers intended for determining the relative content of ortho and para water isomers is described. A double-heterostructure GaInAsP laser is used as a source of tunable IR radiation in the 1.37-μm region. The spectrometer was used for the diagnostics of spin-selective absorption in water isomers.