Walker Jim S, Carruthers Antonia E, Orr-Ewing Andrew J, Reid Jonathan P
School of Chemistry, University of Bristol, Bristol, United Kingdom BS8 1TS.
J Phys Chem Lett. 2013 May 16;4(10):1748-52. doi: 10.1021/jz4008068. Epub 2013 May 9.
A Bessel beam optical trap is combined with continuous wave cavity ringdown spectroscopy to measure the extinction cross section of individual aerosol particles. Particles, ∼1 μm in size, can be captured indefinitely and processes that transform size or refractive index studied. The measured light extinction induced by the particle is shown to depend on the position of the particle in the cavity, allowing accurate measurements of the mode structure of a high finesse optical cavity without significant perturbation. The variation in extinction efficiency of a sodium chloride droplet with relative humidity is shown to agree well with predictions from Mie scattering theory.
将贝塞尔光束光阱与连续波腔衰荡光谱相结合，用于测量单个气溶胶颗粒的消光截面。尺寸约为1μm的颗粒能够被无限期捕获，并可研究改变颗粒尺寸或折射率的过程。结果表明，由颗粒引起的测量光消光取决于颗粒在腔内的位置，从而能够在不产生显著扰动的情况下精确测量高精细度光学腔的模式结构。氯化钠液滴的消光效率随相对湿度的变化与米氏散射理论的预测结果吻合良好。
