Polarimeter and method for measuring the Faraday rotation angle of an object to be measured

摘要

PROBLEM TO BE SOLVED: To enable measurement of a polarizing angle rotation generated by an object to be measured even when another object generating polarizing angle rotation exists besides the object to be measured, and enable measurement of the polarizing angle rotation for measuring the electron density of tokamak equipment. SOLUTION: Two different wavelengths are used as the wavelength of a light source. A laser beam which has passed a plasma enters an HgCdTe detector 16 through a pair of photoelastic modulators 10, 12 and a polarizer 14. Orthogonal components of the incident laser beam are detected by the HgCdTe detector 16, and amplified by lock-in amplifiers 18, 19. From the output ratio, the rotation of the polarizing angle is measured.