Optical measurement apparatus

An optical measurement apparatus, comprising:

• a polarized light irradiation unit that irradiates a subject with irradiation light of which polarization is controlled;
• and
• a polarization imaging unit that images a polarization state of measurement light occurring by irradiating the subject with the irradiation light, and measures a variation of a polarized component occurring between the irradiation light and the measurement light;
• wherein the irradiation light is partially polarized light having a degree of polarization of 50 to 100% or fully polarized light, and ellipticity of the fully polarized component is 50 to 100%,
• the polarization imaging unit includes a polarization imaging mechanism that is capable of calculating, on the basis of a difference between two images including a right-handed circularly polarized component and a left-handed circularly polarized component, at least an element of Stokes parameters which represents a difference between optical intensities of these polarized components among Stokes parameters of the subject, and
• the polarization imaging mechanism includes a polarization diffraction grating that spatially separates the incident measurement light into a left-handed circularly polarized component and a right-handed circularly polarized component, and performs calculation of the element of Stokes parameter which represents the difference in optical intensity of the polarized components from a snapshot captured by imaging the subject with a wavelength of 900 nm or more.