Infrared circular dichroism measuring apparatus and infrared circular dichroism measuring method

An infrared circular dichroism measuring apparatus comprising:

• an IR light source radiating IR light beams;
• an interferometer for allowing the IR light beams to interfere to generate an interference light beam;
• a polarized light beam generator for making the interference light beam into a linearly polarized light beam;
• a circularly polarized light beam generator for converting the linearly polarized light beam into clockwise and counter clockwise circularly polarized light beams at a predetermined modulation frequency and irradiating the circularly polarized light beams on a sample;
• a detector for detecting the circularly polarized light beams that have passed through the sample and generating a detection signal;
• a DC signal extractor for extracting from the detected signal an interferogram by the IR absorption of the sample;
• an AC signal extractor for extracting from the detected signal an interferogram by each of the clockwise and counterclockwise circularly polarized light beams;
• a calculator for conducting a Fourier transformation and calculating the circular dichroism and IR absorption, based on each of the interferograms extracted by the extractors;
• and
• a selective transmitter for narrowing down the wavelength region to be measured, based on a wavelength region in an IR absorption band corresponding to a vibration mode of a structure to be measured in the sample molecule.