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POLARIZER, OPTICAL APPARATUS, LIGHT SOURCE APPARATUS, AND IMAGE PICKUP APPARATUS

  • US 20150130983A1
  • Filed: 11/06/2014
  • Published: 05/14/2015
  • Est. Priority Date: 11/13/2013
  • Status: Abandoned Application
First Claim
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1. A polarizer comprising:

  • a first medium disposed at an emission side;

    a second medium disposed at an incident side; and

    a plurality of laminated structures provided at a predetermined grating period in a grating period direction, wherein;

    the laminated structure includes, in order from the first medium to the second medium, a first dielectric layer, a metallic layer, and a second dielectric layer between the first medium and the second medium,the polarizer is configured to reflect or absorb polarized light oscillating in a direction orthogonal to the grating period direction in a specific wavelength band and to transmit light other than the polarized light, andthe polarizer satisfies;


    0.85<

    ne*P*cos θ



    <

    1.15
    and
    nH1−

    na>

    0.5
    or
    nH2−

    nb>

    0.5,where λ

    represents a wavelength at which a transmittance of the polarized light is minimum, P represents the predetermined grating period, na represents a refractive index of the first medium, and nb represents a refractive index of the second medium, andwhere ne represents an effective refractive index of the first dielectric layer or the second dielectric layer in a direction orthogonal to the grating period direction and parallel to a longitudinal direction of the first dielectric layer or the second dielectric layer, nH1 represents a refractive index of the first dielectric layer, nH2 represents a refractive index of the second dielectric layer, and θ

    represents an incident angle of light to the second medium, and ne is given by;


    ne=[nH12*W12/P2+nf2*(1−

    W1)2/P2]0.5 where W1 represents a grating width of the first dielectric layer, and of represents a refractive index of a medium between each laminated structure, or
    ne=[nH22*W22/P2+nf2*(1−

    W2)2/P2]0.5 where W2 represents a grating width of the second dielectric layer.

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