| Spectral broadening induced by intense ultra-short pulse in 4H–SiC crystals |
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| 引用本文： | 徐春华,闫腾飞,王刚,王文军,梁敬魁,陈小龙. Spectral broadening induced by intense ultra-short pulse in 4H–SiC crystals[J]. 中国物理 B, 2016, 25(6): 64206-064206. DOI: 10.1088/1674-1056/25/6/064206 |
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| 作者姓名： | 徐春华 闫腾飞 王刚 王文军 梁敬魁 陈小龙 |
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| 作者单位： | 1.Research and Development Center for Functional Crystals, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China;2.State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China;3.Collaborative Innovation Center of Quantum Matter, Beijing 100084, China |
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| 基金项目： | Project supported by the National High Technology Research and Development Program of China (Grant No. 2014AA041402) and the National Natural Science Foundation of China (Grant Nos. 51272276 and 51322211). |
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| 摘 要： | We report the observation of spectral broadening induced by 200 femtosecond laser pulses with the repetition rate of 1 kHz at the wavelength of 532 nm in semi-insulating 4H–SiC single crystals.It is demonstrated that the full width at half maximum of output spectrum increases linearly with the light propagation length and the peak power density,reaching a maximum 870 cm~(-1)on a crystal of 19 mm long under an incident laser with a peak power density of 60.1 GW/cm~2.Such spectral broadening can be well explained by the self-phase modulation model which correlates time-dependent phase change of pulses to intensity-dependent refractive index.The nonlinear refractive index n_2 is estimated to be1.88×10~(-15)cm~2/W.The intensity-dependent refractive index is probably due to both the nonlinear optical polarizability of the bound electrons and the increase of free electrons induced by the two-photon absorption process.Super continuum spectra could arise as crystals are long enough to induce the self-focusing effect.The results show that SiC crystals may find applications in spectral broadening of high power lasers.
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| 收稿时间： | 2016-03-01 |
Spectral broadening induced by intense ultra-short pulse in 4H-SiC crystals |
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| Affiliation: | 1.Research and Development Center for Functional Crystals, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China;2.State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China;3.Collaborative Innovation Center of Quantum Matter, Beijing 100084, China |
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| Abstract: | We report the observation of spectral broadening induced by 200 femtosecond laser pulses with the repetition rate of 1 kHz at the wavelength of 532 nm in semi-insulating 4H-SiC single crystals. It is demonstrated that the full width at half maximum of output spectrum increases linearly with the light propagation length and the peak power density, reaching a maximum 870 cm-1 on a crystal of 19 mm long under an incident laser with a peak power density of 60.1 GW/cm2. Such spectral broadening can be well explained by the self-phase modulation model which correlates time-dependent phase change of pulses to intensity-dependent refractive index. The nonlinear refractive index n2 is estimated to be 1.88×10-15 cm2/W. The intensity-dependent refractive index is probably due to both the nonlinear optical polarizability of the bound electrons and the increase of free electrons induced by the two-photon absorption process. Super continuum spectra could arise as crystals are long enough to induce the self-focusing effect. The results show that SiC crystals may find applications in spectral broadening of high power lasers. |
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| Keywords: | spectral broadening SiC self-phase modulation intensity-dependent refractive index |
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