Terahertz spectrometry device and method, and nonlinear optical crystal inspection device and method

摘要

When light beams of two different wavelengths applied from an excitation light source are made incident on a nonlinear optical crystal having a unique nonlinear coefficient, the nonlinear optical crystal generates THz waves resulting from difference frequency generation according to the nonlinear coefficient that the crystal itself has and SHG waves in which the light beams of two different wavelengths have been wavelength converted in accordance with the nonlinear coefficient. The generated THz waves pass through or are reflected from a sample and are detected by a THz detector. The SHG waves are detected by a SHG detector. A control unit acquires THz measurement values T from the THz detector, acquires SHG measurement values S from the SHG detector, and uses baseline THz measurement values TB and baseline SHG measurement values SB acquired without the sample to perform baseline correction using (T/S)/(TB/SB).

主权项

1. A terahertz spectrometry device comprising:
a nonlinear optical crystal that has a unique nonlinear coefficient and generates, from light beams of two different wavelengths made incident thereon, terahertz waves resulting from sum frequency generation or difference frequency generation according to the nonlinear coefficient and optical harmonics in which the light beams of two different wavelengths have been wavelength converted in accordance with the nonlinear coefficient; first detecting means that directly detects the terahertz waves generated from the nonlinear optical crystal or detects measurement terahertz waves that have passed through or been reflected from a measurement target to which the terahertz waves have been applied; second detecting means that detects at least one of the optical harmonics generated from the nonlinear optical crystal; and measuring means that obtains measurement values in which an intensity of the measurement terahertz waves detected by the first detecting means has been corrected on the basis of an intensity of the at least one optical harmonic detected by the second detecting means.