Method for designing focus-length-controllable and one-dimensional photonic crystal flat concave mirror

Abstract

The invention discloses a method for designing a focus-length-controllable and one-dimensional photonic crystal flat concave mirror. The one-dimensional photonic crystal flat concave mirror is composed of one-dimensional photonic crystals formed through the alternate arrangement of a material A and a material B. Circular rings of fixed thickness are stacked up to form the one-dimensional photonic crystal flat concave mirror, wherein the structural parameters of photonic crystals are adopted as one unit of the circular rings and the internal diameters of the circular rings are gradually increased from bottom to top. The emitting surface of the one-dimensional photonic crystal flat concave mirror is in the form of a recessed surface formed through connecting the upper edges of adjacent circular rings. According to the technical scheme of the invention, the flat concave mirror is controllable in focus length. In this way, the structural parameters of a flat concave mirror of any focal length within a certain range can be automatically designed, and the incident ray and the emergent ray are positioned at the two ends of the incident plane of the flat concave mirror. Meanwhile, the method has no special requirement on the polarization state of the incident ray, and breaks through the dependency on the polarization of surface plasmon lens. Moreover, the light focusing in both the TE polarization state and the TM polarization state is realized at the same time. The method is also applicable to linearly polarized lights. The invention has the advantages of simple design method and simple manufacture. By adopting the design method, the design cycle is shortened.

Description

technical field [0001] The invention belongs to the field of artificial microstructure materials and fine light field regulation, and in particular relates to a design method of a plano-concave mirror with controllable focal length. Background technique [0002] With the development of scientific processing technology, it is now possible to process materials as small as nanometers, and these materials have many special effects that they do not have at the macro scale, such as quantum size effects, small size effects, surface and Therefore, it has broad application prospects in the fields of communication, biomedicine, sensing and storage. Artificial microstructured materials refer to the structural design and integration of materials in the micro-nano scale range to achieve flexible control of electromagnetic waves and obtain some novel optical properties. [0003] Compared with scalar beams, vector beams with non-uniform distribution of polarization state contain more abun...

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Problems solved by technology

GiladM.Lerman and others experimentally verified the focusing of radially polarized light by the plasmonic lens in the article entitled "Demonstration of Nanofocusing by the use of PlasmonicLens Illuminated with Radially Polarized Light", see NANOLETTERS Volume 9, Issue 5, Page 2139-2143, but the plasmonic lens The plasmon is a coupling mode of the evanescent wave, which cannot propagate for a long distance, and can only focus near the lens surface. Due to the polarization-dependent conditions of the plasmon excitation, its sub-wavelength focusing for CVB is limited to a radius of polarized light

[0005] In addition, the traditional parabolic mirror makes the beam converge in the same direction through the transformation of the wavefront, and can also focus tightly on the depth of the radially polarized light. on the same side of the mirror, it is difficult to achieve effective application

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