Wang Wei-Bo, Chen De-Ying, Fan Rong-Wei, Xia Yuan-Qin
Institute of Optoelectronics, Harbin Institute of Technology, Harbin 150001, China.
Guang Pu Xue Yu Guang Pu Fen Xi. 2010 Feb;30(2):462-5.
The effects of the stability of dye laser on the signal to noise ratio in degenerate four-wave mixing (DFWM) were first investigated in iodine vapor using forward geometries. Frequency-doubled outputs from a multi-mode Nd : YAG laser pumped dye laser with laser dye PM580 dissolved in ethanol was used. With the help of forward compensated beam-split technique and imaging detecting system, the saturation intensity of DFWM spectrum in the iodine vapor at 5 554.013 nm was first measured to be 290 microJ under the condition of atmospheric pressure and room temperature. The features of the dye laser such as wavelength ranges, beam quality and energy conversion efficiency decreased gradually with increasing pumping service use, pulse number and intensity. Additionally, with the comparison of the stable and unstable dye laser output, it was found that the instability of dye laser output had greatly influenced the DFWM signal and decreased the signal to background noise ratio. Shot to shot jitter and the broadening in the output frequency leads to an effective broadening of the recorded spectrum and loss of the DFWM signal to noise ratio under the same pumping intensity at different time. The study is of importance to the detection of trace atom, molecule and radical in combustion diagnosis.
首次利用正向几何结构在碘蒸气中研究了染料激光稳定性对简并四波混频（DFWM）中信噪比的影响。使用的是由多模Nd:YAG激光泵浦的染料激光器产生的倍频输出，该染料激光器中溶解于乙醇的激光染料为PM580。借助正向补偿分束技术和成像检测系统，在大气压力和室温条件下，首次测得碘蒸气中5554.013nm处DFWM光谱的饱和强度为290微焦。随着泵浦使用次数、脉冲数和强度的增加，染料激光器的波长范围、光束质量和能量转换效率等特性逐渐下降。此外，通过比较稳定和不稳定的染料激光输出发现，染料激光输出的不稳定性对DFWM信号有很大影响，并降低了信背比。逐次脉冲抖动和输出频率展宽导致记录光谱有效展宽，且在不同时间相同泵浦强度下DFWM信噪比降低。该研究对燃烧诊断中痕量原子、分子和自由基的检测具有重要意义。
