Spectroscopic Measurement Device

A spectroscopic measurement apparatus comprising:

• a pulsed laser light source configured to emit pulsed laser light;
• a beam splitter configured to split the pulsed laser light into first light and second light;
• a delay circuit configured to change a delay time of the first light with respect to the second light;
• a chopper configured to intensity-modulate the first light;
• a wavelength converter configured to wavelength-convert the second light into vacuum ultraviolet light;
• an optical system configured to guide the first light that is intensity-modulated and the second light that is wavelength-converted to a sample to be measured, wherein the sample is disposed in a vacuum chamber;
• and
• a detector configured to detect the second light reflected by the sample or the second light transmitted through the sample.

A method of operating a spectroscopic measurement apparatus, the method comprising:

• splitting pulsed laser light from a pulsed laser light source into first light and second light using a beam splitter;
• changing a delay time of the first light with respect to the second light using a delay circuit;
• intensity-modulating the first light using a chopper;
• wavelength-converting the second light into vacuum ultraviolet light using a wavelength converter;
• guiding the first light that is intensity-modulated and the second light that is wavelength-converted to a sample to be measured using an optical system, wherein the sample is disposed in a vacuum chamber;
• and
• detecting the second light reflected by the sample or the second light transmitted through the sample using a detector.