Near-confocal cavity-enhanced Raman spectroscopy for multitrace-gas detection

Simultaneous detection of multitrace gas is still a challenge. Near-confocal cavity-enhanced Raman spectroscopy is proposed and demonstrated for simultaneous detection of multitracegas. With a 200 mW incident laser, the excitation power of > 9 W forms at two foci of the near-confocal cavity owing to the beam being reflected 50 times. High-power excitation light greatly enhances the detection sensitivity of the Raman system. Using this cavity-enhancing technique, high-sensitivity detection of the mixture of eight gases with same Volume ratio has been achieved. This technique may be applied for detecting multitrace gas in many areas. (c) 2008 Optical Society of America