Shirmohammad Maryam, Short Michael A, Zeng Haishan
Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1, Canada.
Imaging Unit, Integrative Oncology Department, BC Cancer Research Institute, Vancouver, BC V5Z 1L3, Canada.
Bioengineering (Basel). 2023 Oct 3;10(10):1161. doi: 10.3390/bioengineering10101161.
We previously developed a hollow-core photonic crystal fiber (HCPCF) based Raman scattering enhancement technique for gas/human breath analysis. It enhances photon-gas molecule interactions significantly but is still based on CW laser excitation spontaneous Raman scattering, which is a low-probability phenomenon. In this work, we explored nanosecond/sub-nanosecond pulsed laser excitation in HCPCF based fiber enhanced Raman spectroscopy (FERS) and successfully induced stimulated Raman scattering (SRS) enhancement. Raman measurements of simple and complex gases were performed using the new system to assess its feasibility for gas analysis. We studied the gas Raman scattering characteristics, the relationship between Raman intensities and pump energies, and the energy threshold for the transition from spontaneous Raman scattering to SRS. H, CO, and propene (CH) were used as test gases. Our results demonstrated that a single-beam pulsed pump combined with FERS provides an effective Raman enhancement technique for gas analysis. Furthermore, an energy threshold for SRS initiation was experimentally observed. The SRS-capable FERS system, utilizing a single-beam pulsed pump, shows great potential for analyzing complex gases such as propene, which is a volatile organic compound (VOC) gas, serving as a biomarker in human breath for lung cancer and other human diseases. This work contributes to the advancement of gas analysis and opens alternative avenues for exploring novel Raman enhancement techniques.
我们之前开发了一种基于空心光子晶体光纤（HCPCF）的拉曼散射增强技术，用于气体/人体呼吸分析。它显著增强了光子与气体分子的相互作用，但仍基于连续波激光激发的自发拉曼散射，这是一种低概率现象。在这项工作中，我们探索了基于HCPCF的光纤增强拉曼光谱（FERS）中的纳秒/亚纳秒脉冲激光激发，并成功实现了受激拉曼散射（SRS）增强。使用新系统对简单气体和复杂气体进行了拉曼测量，以评估其用于气体分析的可行性。我们研究了气体拉曼散射特性、拉曼强度与泵浦能量之间的关系，以及从自发拉曼散射转变为SRS的能量阈值。使用氢气、一氧化碳和丙烯（CH）作为测试气体。我们的结果表明，单光束脉冲泵浦与FERS相结合为气体分析提供了一种有效的拉曼增强技术。此外，通过实验观察到了SRS起始的能量阈值。利用单光束脉冲泵浦的具备SRS功能的FERS系统，在分析复杂气体如丙烯方面显示出巨大潜力，丙烯是一种挥发性有机化合物（VOC）气体，可作为肺癌和其他人类疾病的人体呼吸生物标志物。这项工作有助于推动气体分析的发展，并为探索新型拉曼增强技术开辟了新途径。
