IMMERSION ZONE PLATE WITH SUBWAVELENGTH RESOLUTION Russian patent published in 2022 - IPC G02B5/18 

FIELD: optical instrumentation.

SUBSTANCE: invention relates to the field of optical instrumentation and concerns a phase zone plate. The phase zone plate consists of a transparent substrate on the surface of which a phase-inverse structure with Fresnel zone boundaries is placed. The substrate is made in the form of a truncated cone with a cone height approximately equal to the focal length of the zone plate, with the ratio of the radii of the upper and lower bases of the truncated cone in the range from 0.55 to 0.65, and with a refractive index of the material no less than the refractive index of the phase-inverse structure material. The substrate is directed with a smaller base towards the radiation focusing area, the focal length is no more than the wavelength of the radiation used and the irradiation of the phase zone plate is carried out from the side of the phase-inverse structure.

EFFECT: providing the possibility of focusing the radiation into an axisymmetric focal spot with a subwavelength size.

1 cl, 2 dwg