Spectroscopy using active diode laser stabilization by optical feedback

摘要: A cavity ring down spectroscopy (CRDS) system uses a free-running continuous wave (c.w.) diode laser stabilized by frequency-shifted optical feedback in the presence of strong reflections from high-finesse Fabry-Perot resonator. The stabilization eliminates need for tightly controlling relative positions and Non-frequency-shifted is used linewidth broadening. An acousto-optic modulator placed between output resonator input frequency-shifts light reflected input, causing to cycle phase with period equal inverse frequency-shift. can be several MHz high resolution species at low pressures, hundred lower atmospheric pressures.