LASER LIGHT IRRADIATOR FOR LASER RAMAN MICROPROBE

摘要

PURPOSE:To enable a highly sensitive measurement of Raman spectrum at a micropoint with a reduction in laser reflected light by providing a polarizing cube type beam splitter to improve the irradiation intensity of laser light and the focusing efficiency of Ramam scattered lights. CONSTITUTION:A laser light 3 with the polarization plane turned vertical to the paper of the drawing is focused with a condenser lens 4, deflected by 90 deg. at the efficiency of more than 99% with a separation plane 6 of a polarization cube type beam splitter 5 and then, irradiates a sample 8 via an object lens 7. Raman scattered lights 9 radiated from the sample 8 transmits with the splitter 5 at the efficiency of more than 90% and an image is formed on an incident slit 12 of a spectrophotometer with a condenser lens 11. A laser reflected light portion 10 reflected from the sample 8 is deflected at the efficiency of more than 99% in the incident direction on the separation plane 6 of the slitter 5. This elevates the intensity of the irradiation laser light and the efficiency of focusing Raman scattered lights thereby reducing reflected laser lights causing a stray light. Thus, the detection sensitivity can be improved significantly to enable a highly sensitive measurement of Raman spectrum at a micro-point.