POLARIZATION SPLIT ELEMENT AND PRODUCTION METHOD THEREOF, AND OPTICAL PICKUP, OPTICAL DEVICE, OPTICAL ISOLATOR AND POLARIZING HOLOGRAM PROVIDED WITH THE POLARIZATION SPLIT ELEMENT

摘要

A polarization split element (1) comprising a substrate (2) and a plurality of ridge-form protrusions (3) provided in parallel to each other and at equal intervals on the substrate (2), light (4) incident to the plurality of protrusions (3) being polarization-split by diffraction. The polarization split element (1) satisfies, when the refractive index of the protrusions (3) with respect to incident light (4) is n, a sum of the interval between adjacent protrusions (3) and width of the protrusions (3), or a lattice period P, and the wavelength of the incident light (4) λ, the conditions 1.6≤n≤2.2 and 0.6≤P/λ≤0.8, and splits the incident light (4) into a TM polarization zero-order diffraction light where the vibration direction of magnetic field is the same as the direction of the length of the protrusions (3), and a TE polarization first-order diffraction light where the vibration direction of electric field is the same as the direction of the length of the protrusions (3). The arrangement of this polarization split element (1) can have its lattice height and aspect ratio reduced while retaining its performance at a high level.