The invention discloses a polaroid sheet with a subwavelength
grating structure, which comprises a transparent substrate, a
dielectric grating, a first
metal layer and a second
metal layer. The
dielectric grating is provided with ridges and grooves which are periodically arranged at intervals, the first
metal layer is covered on the ridges of the
dielectric grating, the second metal layer is covered in the grooves of the dielectric grating, and the period of the dielectric grating is less than the
wavelength of incident light. The invention is characterized in that: a high
refractive index dielectric layer is arranged between the transparent substrate and the dielectric grating, and the
refractive index of the high
refractive index dielectric layer is between 1.6 and 2.4. The transmission efficiency and the
extinction ratio of TM light of the polaroid sheet are improved by adding the high refractive index
dielectric layer between the transparent substrate and the dielectric grating. In the whole visible light waveband, the polaroid sheet has
high transmission efficiency, high
extinction ratio, and wide incident angle range. In the process, a nano-imprint technique is adopted to process and produce, the production process is simple and convenient and is easy to operate, an
etching process is not needed, and the
processing cost is reduced.