| 摘要 |
PROBLEM TO BE SOLVED: To reduce measurement noises and enable highly accurate measurement by setting an oscillation wavelength-stabilizing means to a light source for emitting a light for measurement. SOLUTION: An oscillation wavelength-stabilizing means 30 is set to a semiconductor laser 14 as a wavelength-stabilized laser. A light beam 13 passing a half-wave plate of the oscillation-stabilizing means 30 is branched by a beam splitter 32, enters a reflecting type grating 33 and is selected in wavelength to a considerably narrow spectral state. The beam is reflected back in an opposite direction to an incident optical path and fed back to the semiconductor laser 14 via the beam splitter 32 and the half-wave plate 31. Since the rear end face of the semiconductor laser 14 and the reflecting type grating 33 constitute an external resonator, an oscillation wavelength of the semiconductor laser 14 is locked and stabilized to a selected wavelength of the reflection type grating 33. Accordingly, the intensity and the intensity distribution of evanescent light emitted from the minute opening of a minute opening probe will not vary due to the wavelength change of the light beam 13.
|
