• High Power Laser Science and Engineering
  • Vol. 7, Issue 1, 010000e9 (2019)
Gang Xia1、2、3, Wei Fan1、2, Dajie Huang1、2, He Cheng1、2, Jiangtao Guo1、2、3, and Xiaoqin Wang1、2、3
Author Affiliations
  • 1Key Laboratory of High Power Laser and Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
  • 2National Laboratory on High Power Laser and Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
  • 3University of Chinese Academy of Sciences, Beijing 100049, China
  • show less
    (a) Structure of the LC binary mask (1 – anti-reflection coating, 2 – front glass substrate, 3 – anti-reflection coating, 4 – polyimide layer, 5 – LC molecule, 6 – azobenzene group, 7 – photoalignment layer, 8 – anti-reflection coating, 9 – rear glass substrate and 10 – anti-reflection coating) and (b) arrangement of LC molecules in a single pixel of two pixel types (1 – incident light, 2 – polarizer, 3 – P-polarized light, 4 – front glass substrate with coating polyimide, 5 – LC molecule, 6 – rear glass substrate with coating azobenzene, 7 – P-polarized light, 8 – polarizer, 9 – output light and 10 – S-polarized light).
    Fig. 1. (a) Structure of the LC binary mask (1 – anti-reflection coating, 2 – front glass substrate, 3 – anti-reflection coating, 4 – polyimide layer, 5 – LC molecule, 6 – azobenzene group, 7 – photoalignment layer, 8 – anti-reflection coating, 9 – rear glass substrate and 10 – anti-reflection coating) and (b) arrangement of LC molecules in a single pixel of two pixel types (1 – incident light, 2 – polarizer, 3 – P-polarized light, 4 – front glass substrate with coating polyimide, 5 – LC molecule, 6 – rear glass substrate with coating azobenzene, 7 – P-polarized light, 8 – polarizer, 9 – output light and 10 – S-polarized light).
    Fabrication process of the LC cell.
    Fig. 2. Fabrication process of the LC cell.
    Photolithography mask system (1 – light source, 2 – collimating lens, 3 – polarization beam splitter, 4 – LCOS, 5 – imaging system (1:1) and 6 – LC cell).
    Fig. 3. Photolithography mask system (1 – light source, 2 – collimating lens, 3 – polarization beam splitter, 4 – LCOS, 5 – imaging system (1:1) and 6 – LC cell).
    Designed objective function $y=0.8x^{2}+0.2$. (a) Binary distribution of the mask; the unit pixel is $40~\unicode[STIX]{x03BC}\text{m}$. (b) Spatial distribution of the objective function.
    Fig. 4. Designed objective function $y=0.8x^{2}+0.2$. (a) Binary distribution of the mask; the unit pixel is $40~\unicode[STIX]{x03BC}\text{m}$. (b) Spatial distribution of the objective function.
    Beam shaping test system (1 – laser source, 2 – single mode fiber, 3 – fiber port, 4 – beam expander ($20\times$), 5 – polarization beam splitter, 6 – LC binary mask, 7 – polarization beam splitter, 8 – plano-convex lens, 9 – mirror, 10 – pinhole, 11 – mirror, 12 – plano-convex lens and 13 – CCD).
    Fig. 5. Beam shaping test system (1 – laser source, 2 – single mode fiber, 3 – fiber port, 4 – beam expander ($20\times$), 5 – polarization beam splitter, 6 – LC binary mask, 7 – polarization beam splitter, 8 – plano-convex lens, 9 – mirror, 10 – pinhole, 11 – mirror, 12 – plano-convex lens and 13 – CCD).
    Physical LC binary mask. (a) Boundary dimension of the physical LC binary mask. (b) Parabolic pixel distribution is observed in polarized white light. (c) Regional area of the pixel structure examined under a crossed polarizer microscope ($50\times$).
    Fig. 6. Physical LC binary mask. (a) Boundary dimension of the physical LC binary mask. (b) Parabolic pixel distribution is observed in polarized white light. (c) Regional area of the pixel structure examined under a crossed polarizer microscope ($50\times$).
    Parabolic shaping of the LC binary mask (curve 1 is the designed objective function, curve 2 was tested at the completed mask; curve 3 is the transmission curve of the same tested mask, which has been stored for six months in a conventional storage).
    Fig. 7. Parabolic shaping of the LC binary mask (curve 1 is the designed objective function, curve 2 was tested at the completed mask; curve 3 is the transmission curve of the same tested mask, which has been stored for six months in a conventional storage).
    Square soft edge diaphragm of the LC binary mask.
    Fig. 8. Square soft edge diaphragm of the LC binary mask.
    Logo picture of ‘SIOM’ (the size of the picture is 8 mm $\times$ 8 mm; (a) designed picture and (b) picture written on the LC cell).
    Fig. 9. Logo picture of ‘SIOM’ (the size of the picture is 8 mm $\times$ 8 mm; (a) designed picture and (b) picture written on the LC cell).
    Results of written and erased situation. (a) First lithography. (b) Third lithography on the same LC cell. (c) Fifth lithography on the same LC cell. (d) Sixth lithography on the same LC cell. (e) The LC cell erased by a linearly polarized blue light of 10 mW for 5 minutes after the sixth writing. (f) The LC cell erased at the power of 10 mW for extra 3 hours after (e).
    Fig. 10. Results of written and erased situation. (a) First lithography. (b) Third lithography on the same LC cell. (c) Fifth lithography on the same LC cell. (d) Sixth lithography on the same LC cell. (e) The LC cell erased by a linearly polarized blue light of 10 mW for 5 minutes after the sixth writing. (f) The LC cell erased at the power of 10 mW for extra 3 hours after (e).
    SubstrateLaser damage threshold@1064 nm, 10 ns, 1 Hz
    K9 glass 1$62.5385~\text{J}/\text{cm}^{2}$
    K9 glass 2$62.9698~\text{J}/\text{cm}^{2}$
    Ultraclear float glass$54.34~\text{J}/\text{cm}^{2}$
    Table 1. Laser damage thresholds of the azobenzene-based photoalignment layers.
    MaterialLaser damage
    threshold@1064 nm, 10 ns, 1 Hz
    LC ($d\sim 5~\unicode[STIX]{x03BC}\text{m}$)$18~\text{J}/\text{cm}^{2}$
    Polyimide ($d=50~\text{nm}$)$15~\text{J}/\text{cm}^{2}$
    Chemical anti-reflection film$30~\text{J}/\text{cm}^{2}$
    Inorganic anti-reflection film$15~\text{J}/\text{cm}^{2}$
    Glass substrate (K9)$50~\text{J}/\text{cm}^{2}$
    Table 2. Laser damage thresholds of the LC binary mask materials.
    Copy Citation Text
    Gang Xia, Wei Fan, Dajie Huang, He Cheng, Jiangtao Guo, Xiaoqin Wang. High damage threshold liquid crystal binary mask for laser beam shaping[J]. High Power Laser Science and Engineering, 2019, 7(1): 010000e9
    Download Citation
    Special Issue: High Energy Density Physics and High Power Lasers 2018
    Received: Jul. 6, 2018
    Accepted: Nov. 30, 2018
    Published Online: Feb. 25, 2019
    The Author Email: