Device for measuring focal length of sub-wavelength optical imaging device and its measuring method

Abstract

The invention discloses a focal length measuring device of a sub-wavelength optical imaging device and a measuring method thereof. The device includes a laser, a beam expander collimation system, a sub-wavelength optical imaging device and a standard sample block of a nano-step height; a standard sample block of a nano-step height and a The power device that drives it to move up and down in the vertical direction is connected, and the power device is connected with the computer control system; the surface of the nano-step height standard sample block is coated with photoresist, and the nano-step height standard sample block consists of several on the same vertical surface, etc. Steps arranged at intervals; one of the steps is an intermediate step, and the distance between it and the subwavelength optical imaging device is the focal length design value of the subwavelength optical imaging device; among all the steps, the step height gradually increases from the middle step upwards, The corresponding focal length value decreases, and the step height gradually decreases from the middle step down, and the corresponding focal length value increases; the wavelength of the laser is equal to the wavelength of the incident light source when the subwavelength optical imaging device is designed.

Description

technical field [0001] The invention relates to the field of optical technology, in particular to a focal length measuring device of a sub-wavelength optical imaging device and a measuring method thereof. Background technique [0002] In 2001, Professor L.Kipp of Germany published an article in the journal Nature, first proposing the concept of "photon sieves", which was later translated into "photon sieve", which replaces Fresnel with small holes randomly distributed on the light-transmitting annulus A new type of diffractive optical imaging device formed by the light-transmitting annular zone of the Er structure. After structural optimization, the randomly distributed small holes can effectively suppress secondary and advanced diffraction, thereby improving imaging contrast and resolution, and even breaking the theoretical limit of traditional diffraction imaging to achieve super-resolution imaging. [0003] With the continuous development of nano-imaging technology, peop...

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Problems solved by technology

[0005] Aiming at the above-mentioned deficiencies in the prior art, the focal length measuring device and its measuring method of the sub-wavelength optical imaging device provided by the present invention solve the technical problems of short focal length and difficult measurement through the precisely designed standard sample block of nano-step height

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