Xie J G, Ruekgauer T E, Armstrong R L, Pinnick R G
Opt Lett. 1993 Mar 1;18(5):340-2. doi: 10.1364/ol.18.000340.
Stimulated Raman scattering (SRS) in laser-irradiated microdroplets is suppressed by the addition of nanometersized latex particles. The microdroplets consist of either pure ethanol or a solution of Rhodamine 6G dye in ethanol, seeded with latex particles having diameters of 50 < d < 500 nm. SRS emission occurs at droplet morphology-dependent resonances (MDR's) after either direct pumping by the incident 532-nm laser or indirectly whereby the pump laser first initiates dye lasing, which in turn pumps SRS. For large latex, we observe SRS suppression at a near-coincident threshold concentration independent of the presence of dye, whereas, for small latex, adding dye reduces the threshold concentration by more than an order of magnitude. These findings are consistent with the interpretation that for large latex ~1 particle must occupy the MDR mode volume at threshold, whereas for small latex the addition of particles facilitates Förster-assisted annihilation of both 532-nm and dye-lasing MDR pump photons.
在激光辐照的微滴中，通过添加纳米尺寸的乳胶颗粒可抑制受激拉曼散射（SRS）。微滴由纯乙醇或罗丹明6G染料的乙醇溶液组成，并接种直径为50＜d＜500nm的乳胶颗粒。在由入射的532nm激光直接泵浦后，或者通过泵浦激光首先引发染料激光振荡，进而泵浦SRS的间接方式之后，SRS发射在依赖于液滴形态的共振（MDR）处发生。对于大尺寸乳胶颗粒，我们观察到在接近重合的阈值浓度下SRS受到抑制，且与染料的存在无关；而对于小尺寸乳胶颗粒，添加染料可使阈值浓度降低超过一个数量级。这些发现与以下解释一致：对于大尺寸乳胶颗粒，在阈值时约1个颗粒必须占据MDR模式体积；而对于小尺寸乳胶颗粒，添加颗粒有助于福斯特辅助湮灭532nm和染料激光振荡MDR泵浦光子。
