NEAR-INFRARED DIODE-LASER SPECTROMETER WITH FREQUENCY CALIBRATION USING INTERNAL 2ND HARMONICS

Frequency calibration of a 1.3-mu-m diode laser spectrometer was carried out with a simultaneously recording spectrum of the iodine molecule in the visible region using internal second harmonics from the diode laser itself. An absolute accuracy of 0.002 cm-1 was achieved with the frequency standard spectrum of the iodine molecule in the visible region and frequency markers from an etalon. Several atomic and molecular transitions in the near-infrared region were remeasured using this new frequency reference.