• Laser & Optoelectronics Progress
  • Vol. 56, Issue 4, 040004 (2019)
Gang Bai1、2, Yifeng Yang1, Yunxia Jin1, Bing He1、3、*, and Jun Zhou1、4、**
Author Affiliations
  • 1 Shanghai Key Laboratory of All Solid-State Laser and Applied Techniques, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
  • 2 University of Chinese Academy of Sciences, Beijing 100049, China
  • 3 Nanjing Institute of Advanced Laser Technology, Nanjing, Jiangsu 210038, China
  • 4 Nanjing Zhongke Shenguang Technology Co., Ltd., Nanjing, Jiangsu 210038, China
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    DOI: 10.3788/LOP56.040004 Cite this Article Set citation alerts
    Gang Bai, Yifeng Yang, Yunxia Jin, Bing He, Jun Zhou. Research Progress on Laser Beam Characteristics in Spectral Beam Combining System[J]. Laser & Optoelectronics Progress, 2019, 56(4): 040004 Copy Citation Text show less
    Output power versus year for high-brightness fiber SBC (defined as M2≤2)[33]
    Fig. 1. Output power versus year for high-brightness fiber SBC (defined as M2≤2)[33]
    Experimental setup for SBC of 30 kW fiber lasers[33]
    Fig. 2. Experimental setup for SBC of 30 kW fiber lasers[33]
    Experimental setup for SBC of 9.6 kW fiber laser at China Academy of Engineering Physics[39]
    Fig. 3. Experimental setup for SBC of 9.6 kW fiber laser at China Academy of Engineering Physics[39]
    Experimental setup for SBC of 11.27 kW fibers in Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences
    Fig. 4. Experimental setup for SBC of 11.27 kW fibers in Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences
    SBC system based on MLD grating. (a) Schematic; (b) simplified model
    Fig. 5. SBC system based on MLD grating. (a) Schematic; (b) simplified model
    Beam deviation of incident laser array. (a) Axial translation; (b) angular deflection
    Fig. 6. Beam deviation of incident laser array. (a) Axial translation; (b) angular deflection
    M2 factors of laser array under different beam deviations. (a) Axial translation σx; (b) angular deflection σθ
    Fig. 7. M2 factors of laser array under different beam deviations. (a) Axial translation σx; (b) angular deflection σθ
    Beam width versus propagation distance for different quartic-aberration coefficients[18]
    Fig. 8. Beam width versus propagation distance for different quartic-aberration coefficients[18]
    Beam quality versus focal length of transform lens[19]
    Fig. 9. Beam quality versus focal length of transform lens[19]
    Thermal distortion at MLD grating surface. (a) Structural diagram of experimental measurement; (b) interferograms observed with and without laser irradiation[49]
    Fig. 10. Thermal distortion at MLD grating surface. (a) Structural diagram of experimental measurement; (b) interferograms observed with and without laser irradiation[49]
    Far-field intensity distributions of combined beam and single beam under different power densities. (a) No deformation; (b) irradiation power 1 kW·cm-2; (c) irradiation power 2 kW·cm-2; (d) irradiation power 3 kW·cm-2 [22]
    Fig. 11. Far-field intensity distributions of combined beam and single beam under different power densities. (a) No deformation; (b) irradiation power 1 kW·cm-2; (c) irradiation power 2 kW·cm-2; (d) irradiation power 3 kW·cm-2 [22]
    Change on MLD grating surface after laser irradiation with average power density of 3.6 kW·cm-2. (a) Surface temperature distribution; (b) thermal deformation distribution
    Fig. 12. Change on MLD grating surface after laser irradiation with average power density of 3.6 kW·cm-2. (a) Surface temperature distribution; (b) thermal deformation distribution
    Results of MLD gratings under different deformation heights. (a) Near-field phase modulation; (b) far-field intensity distributions
    Fig. 13. Results of MLD gratings under different deformation heights. (a) Near-field phase modulation; (b) far-field intensity distributions
    Experimental setup for thermal deformation detection of MLD grating
    Fig. 14. Experimental setup for thermal deformation detection of MLD grating
    Interference fringe patterns under laser irradiation with different power densities
    Fig. 15. Interference fringe patterns under laser irradiation with different power densities
    Far-field intensity distributions under laser irradiation with different power densities. (a) 0; (b) 3.6 kW·cm-2
    Fig. 16. Far-field intensity distributions under laser irradiation with different power densities. (a) 0; (b) 3.6 kW·cm-2
    Far-field intensity distributions of combined beam when incident lasers with different linewidths diffracted by MLD grating. (a) 0.07 nm; (b) 0.15 nm; (c) 0.19 nm; (d) 0.25 nm; (e) 0.30 nm; (f) 0.41 nm
    Fig. 17. Far-field intensity distributions of combined beam when incident lasers with different linewidths diffracted by MLD grating. (a) 0.07 nm; (b) 0.15 nm; (c) 0.19 nm; (d) 0.25 nm; (e) 0.30 nm; (f) 0.41 nm
    Beam quality factor M2 versus incident laser linewidth
    Fig. 18. Beam quality factor M2 versus incident laser linewidth
    ParameterSiO2HfO2Fusedsilica
    Density /(kg·m-3)2100103002200
    Specific heat /(J·kg-1·K-1)722146670
    Heat conductivity /(W·m-1·K-1)7.60.6471.4
    Thermal expansion /(10-6 K-1)0.55.80.55
    Young's modulus /GPa73.117072
    Poisson's ratio0.170.270.17
    Table 1. Thermophysical parameters of MLD grating materials
    Deformation height h /nm050100150
    Beam quality M21.001.482.663.82
    Table 2. Beam quality of combined beam for MLD gratings with different maximum deformation heights
    Gang Bai, Yifeng Yang, Yunxia Jin, Bing He, Jun Zhou. Research Progress on Laser Beam Characteristics in Spectral Beam Combining System[J]. Laser & Optoelectronics Progress, 2019, 56(4): 040004
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