OPTICAL CHARACTERISTIC MEASURING INSTRUMENT

PROBLEM TO BE SOLVED: To provide an optical characteristic measuring instrument which can measure optical characteristics of an optical component used for a stepper, etc., and has a sufficient quantity of light even when a polarizing element is used. SOLUTION: The light from a laser light source 1 has its aperture angle limited by an aperture 11. The laser light is never spread by diffraction at the aperture 11, so the aperture angle can easily be made small. The light whose quantity is adjusted by an ND filter 6 is made incident on a polarizing element 12 and so adjusted as to have target polarization characteristics, and the light is made incident on an optical demultiplexing raw glass 5 arranged obliquely at 45 deg., so that while part of the light is transmitted to enter a sample chamber 2, the rest is reflected to travel to a monitor photodetection part 10. For measurement, the output of a sample photodetector 9 is normalized by a process for division by the output of the monitor photodetector 10 to remove the influence of variation of the incident light (due to variance of the oscillation fluence of, specially, the laser light source 1).