Abstract
Due to the diffraction limit, subwavelength nanoslits (whose width is strictly smaller than λ/2) are hard to resolve by optical microscopy. Here, we overcome the diffraction limit by measuring the full Stokes parameters of the scattered field of the subwavelength nanoslits with varying width under the illumination of a linearly-polarized laser with a 45° polarization orientation angle. Because of the depolarization effect arising from the different phase delay and amplitude transmittance for TM polarization (perpendicular to the long axis of slit) and TE polarization (parallel to the long axis of slit), the state of polarization (SOP) of the scattered light strongly depends on the slit width for subwavelength nanoslits. After correcting for residual background light, the nanoslit width measured by the SOP of scattered light is consistent with the scanning electron microscopy (SEM) measurement. The simulation and experiment in this work demonstrate a new far-field optical technique to determine the width of subwavelength nanoslits by studying the SOP of the scattered light.
© 2022 Optica Publishing Group
Full Article | PDF ArticleMore Like This
Yechuan Zhu, Weizheng Yuan, Wenli Li, Hao Sun, Kunlun Qi, and Yiting Yu
Opt. Lett. 43(2) 206-209 (2018)
Feng Huang, Xiangqian Jiang, Haiming Yuan, Hanning Yang, Siren Li, and Xiudong Sun
Opt. Lett. 41(7) 1684-1687 (2016)
Satoshi Ishii, Alexander V. Kildishev, Vladimir M. Shalaev, Kuo-Ping Chen, and Vladimir P. Drachev
Opt. Lett. 36(4) 451-453 (2011)