초록 ▼

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 a high-finesse Fabry-Perot resonator. The frequency-shifted feedback stabilization eliminates the need for

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 a high-finesse Fabry-Perot resonator. The frequency-shifted feedback stabilization eliminates the need for tightly controlling the relative positions of the laser and resonator. Non-frequency-shifted feedback is used for linewidth broadening. An acousto-optic modulator placed between the diode laser output and the resonator input frequency-shifts light reflected by the resonator input, causing the laser to cycle in phase with a period equal to the inverse of the frequency-shift. The laser diode linewidth can be stabilized from several MHz for high resolution spectroscopy of species at low pressures, to several hundred MHz for lower resolution spectroscopy of species at atmospheric pressures.

대표청구항 ▼

[ what is claimed is:] [1.] A spectroscopy system with active optical feedback stabilization, comprising:a) a diode laser having a laser output;b) a resonant cavity comprising a cavity input and a cavity output, defining an intracavity light path passing through a sample, and situated such that ligh

[ what is claimed is:] [1.] A spectroscopy system with active optical feedback stabilization, comprising:a) a diode laser having a laser output;b) a resonant cavity comprising a cavity input and a cavity output, defining an intracavity light path passing through a sample, and situated such that light extending from said laser output is incident on said cavity input;c) a laser stabilization means in optical communication with said laser output, for providing frequency-shifted feedback light incident on said laser output of a level suitable for stabilizing said laser; andd) a detector in optical communication with said cavity output, for detecting light extending from said cavity output, thereby measuring an interaction of said sample with intracavity light.