Patent ID: 6965475

Claim:
An optical component comprising: a diffraction grating element of transmissive type having a flat plate, and a diffraction grating formed on one surface of said flat plate or formed within said flat plate in parallel with the one surface thereof; and a prism composed of a material with a refractive index of n 1 , said prism having a first surface on which the light diffracted by said diffraction grating element is incident, and a second surface from which the light having passed through the first surface is emitted; wherein said diffraction grating element and said prism are provided within a medium with a refractive index of n 0 ; and wherein, in the case that light with a wavelength λ is incident on said diffraction grating element at an incident angle of θ 0 , then taking the incident angle of the light incident on the first surface of said prism, from said diffraction grating element, to be θ 2 , taking the emission angle of the light emitted from said second surface of said prism to be θ 5 , taking the temperature coefficient of the diffraction angle in said diffraction grating element to be F g , taking the temperature coefficient of the emission angle θ 5 of the light emitted from the second surface of said prism, assuming that the incident angle θ 2 of the light incident on the first surface of said prism is fixed regardless of the temperature, to be F p , and taking the magnification rate of the angular dispersion caused by said prism to be M p , said diffraction grating element and said prism are arranged such that the wavelength λ and the incident angle θ 0 satisfy the following relationship: “n 1 >n 0 AND |θ 5 |>|θ 2 |” or “n 1 <n 0 AND |θ 5 |<|θ 2 |”, whilst also satisfy the following relationship: “−2M p F g <F p <0” or “−2M p F g >F p >0”.