Logozzo Alexander, Preston Thomas C
Department of Atmospheric and Oceanic Sciences and Department of Chemistry, McGill University, 805 Sherbrooke Street West, Montreal, Quebec, Canada H3A 0B9.
J Phys Chem A. 2022 Jan 13;126(1):109-118. doi: 10.1021/acs.jpca.1c09363. Epub 2021 Dec 29.
An optical trapping cell that is capable of suspending particles using two counter-propagating beams in a temperature-controlled environment is reported here. With this dual-beam optical trap, we are able to hold single micron-sized droplets at temperatures down to 253 K (-20 °C) for hours at a time and in metastable (supercooled) states. As particles are trapped at the shared focal points of two intense beams, strong cavity-enhanced Raman scattering (CERS) is observed and allows for high precision measurements of physical properties. Here, the evaporation of highly oxygenated organic systems was monitored using CERS and was used to determine temperature-dependent vapor pressures and enthalpies of vaporization. The wavelength- and temperature-dependent optical properties were also simultaneously retrieved using CERS.
本文报道了一种光学捕获装置，它能够在温度可控的环境中使用两束反向传播的光束来悬浮粒子。利用这种双光束光阱，我们能够在低至253 K（-20°C）的温度下，一次将单个微米级液滴保持数小时，并使其处于亚稳态（过冷态）。由于粒子被捕获在两束强光的共同焦点处，因此观察到了强烈的腔增强拉曼散射（CERS），并可用于高精度测量物理性质。在这里，使用CERS监测了高氧化有机体系的蒸发情况，并用于确定与温度相关的蒸气压和汽化焓。同时，还利用CERS获取了波长和温度相关的光学性质。
