Forked liquid crystal grating preparation method and application of forked liquid crystal grating in vortex beam

A technology of fork-shaped grating and liquid crystal grating, which is applied in the direction of diffraction grating, optics, nonlinear optics, etc., to achieve the effects of high light energy conversion efficiency, low technology implementation cost, and saving mask production cost

Inactive Publication Date: 2014-05-14
NANJING UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Two and three pairs of normal incident lasers exhibit polarization-independent characteristics

Method used

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  • Forked liquid crystal grating preparation method and application of forked liquid crystal grating in vortex beam
  • Forked liquid crystal grating preparation method and application of forked liquid crystal grating in vortex beam
  • Forked liquid crystal grating preparation method and application of forked liquid crystal grating in vortex beam

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0046] This embodiment realizes the patterning of the fork grating and the detection of the diffraction spot of the vortex beam on the TN type liquid crystal cell.

[0047] The CNC micromirror array lithography system is composed of: 405±10nm blue LED light source, through a beam splitting prism (size 25mm×25mm), evenly irradiates to DMD (1024×768 pixels, each pixel 13.68μm, best matching ultraviolet and Blu-ray band), the computer transmits the image control signal to the DMD signal input terminal through the CAD software (constituting the numerical control device); magnification 10 times) miniaturization, a sub-wavelength metal wire grid polarizer (diameter 50mm, extinction ratio greater than 2000:1) is placed 5cm in front of the sample stage; the focus monitoring component is the beam splitting prism and CCD imaging device in the real-time monitoring system ( The industrial ultraviolet-visible-near-infrared imaging CCD is selected and connected to the computer terminal thro...

Embodiment 2

[0053] This embodiment realizes the patterning of the fork-shaped grating on the orthogonal PA type liquid crystal cell.

[0054] The previous exposure steps are the same as in Example 1, the difference is that firstly the two pieces of glass sheets exposed for the first time are glued into a box, and then taken to the DMD system for secondary exposure of the fork-shaped grating pattern. The direction of the secondary exposure is perpendicular to the direction of the primary exposure. The method of making the box and filling the liquid crystal is the same as that of Embodiment 1. Under this method, the liquid crystal molecules in the re-exposed area and the non-re-exposed area in the liquid crystal cell are in parallel PA orientation, but the two orientations are orthogonal to each other. The advantage of this arrangement of liquid crystal molecules is that the diffraction spots and diffraction efficiency produced by it are not dependent on the polarization of incident light....

Embodiment 3

[0056] This embodiment implements the patterning of the fork grating on the orthogonal HAN type liquid crystal cell and measures the diffraction efficiency of the vortex beam diffraction spot of the incident light of different polarization states and different wavelengths. Changing the exposure pattern can realize the rewritable characteristics of the vortex beam.

[0057] The exposure treatment of one of the glass sheets to be made into a liquid crystal cell is the same as in Example 1, and the rubbing alignment treatment is performed on the other sheet. Firstly, the cleaning work of the glass sheet is the same as that in Example 1, and then the PI vertical alignment agent is spin-coated. It should be noted that the PI vertical alignment agent needs to be taken out of the refrigerator 3 to 4 hours before use, and it can be opened and used after it returns to room temperature. Spin-coating parameters were low-speed spin-coating for 6 seconds at a speed of 300 rpm, high-speed ...

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Abstract

A forked liquid crystal grating is characterized in that liquid crystal orientation of adjacent liquid crystal areas of the forked liquid crystal grating is controlled differently such that the following three types of forked liquid crystal gratings can be formed, namely a TN / PA-type forked liquid crystal grating, an orthogonal PA-type liquid crystal grating and an orthogonal HAN-type liquid crystal grating; 90-degree twisted phase microcells of liquid crystal and parallel-oriented microcells of and the liquid crystal are alternately arranged so as to form the TN / PA-type forked liquid crystal grating; uniformly parallel microcells of the liquid crystal of which optical axes are in the same region and microcells in an adjacent region which are orthogonal to each other are alternately arranged to form the orthogonal PA-type liquid crystal grating. According to the preparation of the forked liquid crystal grating, a photoalignment method is adopted to control liquid crystal micro orientation so as to control the director distribution of the liquid crystal. Since a digital?micro-mirror device (DMD)-based micro projection-type lithography system is realized, a digital control device outputs liquid crystal forked gritting pattern signals to control the reflected light of each pixel of a digital?micro-mirror device (DMD), such that the imaging of a liquid crystal forked grating pattern can be realized; and after being narrowed through a micro objective, light beams are projected to photoalignment material agent conductive glass through a polarizing film.

Description

technical field [0001] The invention relates to the technical fields of microlithography system, liquid crystal orientation control, preparation of electro-optical adjustable components, etc., and specifically relates to an electrically adjustable and optically rewritten system based on liquid crystal light control, rubbing orientation and digitally controlled micromirror array DMD lithography system Fabrication of liquid crystal forked gratings and their application in generating optical vortices. Background technique [0002] In recent years, due to the application of vortex beams in optical trapping, manipulation of tiny particles, new super-resolution optical microscopy and astronomy, people have paid more and more attention to the research of vortex beams. There are many ways to generate vortex beams, such as laser resonator and pumping methods, spiral phase plates, and computational holography to generate vortex beams with angular phase factor Ψ 1 = exp(imθ) optical v...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G02B5/18G02F1/1337G02F1/1333G02F1/29
Inventor 胡伟魏冰妍明阳陆延青徐飞
Owner NANJING UNIV
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