WAVELENGTH DETECTING APPARATUS

摘要

PCT No. PCT/JP91/00185 Sec. 371 Date Oct. 8, 1991 Sec. 102(e) Date Oct. 8, 1991 PCT Filed Feb. 15, 1991 PCT Pub. No. WO91/12499 PCT Pub. Date Aug. 22, 1991.A wavelength detecting apparatus which assures that the wavelength of a laser light can be detected with accuracy is disclosed. In the subject invention, the temperature of the vapor obtained from an element such as a mercury which contains plural isotopes is elevated in excess of a predetermined temperature so that an emission line of the element becomes plural emission lines. One of the divided emission lines is used as a reference light for the detection of the wavelength of the light to be detected. In addition, a specific isotope of the element may be selected from plural isotopes of a reference element to thereby provide a narrowed emission line for use as a reference light.