State Key Laboratory for Mesoscopic Physics & Department of Physics, Peking University, Beijing 100871, China.
Opt Lett. 2013 Jun 1;38(11):1802-4. doi: 10.1364/OL.38.001802.
We study the stimulated Raman emission of a high-Q polydimethylsiloxane (PDMS)-coated silica microsphere on a silicon chip. In this hybrid structure, as the thickness of the PDMS coating increases, the spatial distribution of the whispering gallery modes moves inside the PDMS layer, and the light emission switches from silica Raman lasing to PDMS Raman lasing. The Raman shift of the PDMS Raman laser is measured at 2900 cm(-1), corresponding to the strongest Raman fingerprint of bulk PDMS material. The threshold for this PDMS Raman lasing is demonstrated to be as low as 1.3 mW. This type of Raman emission from a surface-coated high-Q microcavity not only provides a route for extending lasing wavelengths, but also shows potential for detecting specific analytes.
我们研究了在硅片上的高 Q 值聚二甲基硅氧烷（PDMS）涂层二氧化硅微球的受激拉曼发射。在这种混合结构中，随着 PDMS 涂层厚度的增加， whispering gallery 模式的空间分布向内 PDMS 层移动，并且光发射从二氧化硅拉曼激射切换到 PDMS 拉曼激射。PDMS 拉曼激光的拉曼位移在 2900 cm(-1)处测量，对应于块状 PDMS 材料的最强拉曼指纹。证明这种 PDMS 拉曼激射的阈值低至 1.3 mW。这种来自表面涂覆的高 Q 值微腔的拉曼发射不仅为扩展激射波长提供了途径，而且还显示出检测特定分析物的潜力。
