INTRACAVITY LASER SPECTROSCOPY IN THE 1.38-1.55 MU-M SPECTRAL REGION USING A MULTIMODE CR(4+)-YAG LASER

Absorption spectra of water vapor are recorded by intracavity laser spectroscopy (ILS) using a multimode Cr4+:YAG laser operating in the 1.38-1.55 mum spectral region. The most prominent water absorption features examined appear near 1.463 muM and are assignable to several rotational transitions in the nu1 +2nu2 overtone band. The observed optical properties of the 1.463 mum water absorption bands (e.g., the dependence of band intensity on the effective optical pathlength or generation time) are consistent with those expected for intracavity measurements with a multimode, homogeneously broadened ILS laser such as a broad-band dye laser. These data demonstrate the applicability of the tunable, solid-state Cr4+:YAG laser for the high sensitivity detection of weak absorption in the near-infrared region via ILS techniques.