1064 nm泵浦乙烷1.55 μm拉曼激光研究

Study on 1.55 μm Raman laser in ethane gas pumped by 1064 nm pulsed laser

  • 摘要: 受激拉曼散射(SRS)作为一种高效的激光频率改变方法,受到广泛关注。但是拉曼激光也存在着明显的不足,其波长缺少连续调谐的能力,因此需要开发更多的拉曼活性介质,提高拉曼频移覆盖密度。以波长为1064 nm的激光作为泵浦源,以高压乙烷作为拉曼活性介质,产生了波长为1550 nm的一阶拉曼(S1),实验过程中未发现明显后向拉曼和高阶拉曼,通过优化实验条件,降低激光诱导击穿(LIB),使S1的光子转化效率提高到了20.7%,最高脉冲能量达到21.2 mJ。并且首次测量了乙烷对1.55 μm激光的吸收系数和吸收截面,它们分别是5.71 \times 10^-8 m−1 ·Pa−1 2.35 \times 10^-24\text cm^2

     

    Abstract: Stimulated Raman scattering is an effective non-linear frequency conversion method, and has received much attention. However, Raman lasers also have drawbacks, such as wavelength of Raman lasers could not be tuned continuously, and the coverage of Raman laser wavelength is limited. Therefore, more Raman active media are required to improve the coverage of Raman lasers. In this work, 1064 nm laser was used as pump source, and pressurized ethane was used as Raman active medium, and 1550 nm Raman laser was produced. Neither obvious backward Raman laser nor higher orders of Stokes Raman lasers were observed in this experiment. By the optimization of experimental parameters, laser induced breakdown was reduced; the first order Stokes(S1) Raman laser photon conversion efficiency was improved to 20.7%, and the maximum S1 energy was 21.2 mJ. Ethane was found to have significant absorption at wavelength of 1550 nm, this was the major reason for the limited photon conversion efficiency and pulse energy of S1 laser. The absorption coefficient of ethane at 1550 nm was measured to be 5.71 \times 10^-8 m−1 ·Pa−1, and the absorption cross section was measured to be 2.35 \times 10^-24\text cm^2 .

     

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