Margheri Giancarlo, Barbosa André Nascimento, Freire Fernando Lazaro, Del Rosso Tommaso
Institute for Complex Systems of National Council of Researches of Italy, Separate Location of Sesto Fiorentino, Via Madonna del Piano, Sesto, 50019 Florence, Italy.
Department of Physics, Pontifícia Universidade Católica do Rio de Janeiro, Rua Marques de São Vicente, Rio de Janeiro 22451-900, Brazil.
Micromachines (Basel). 2022 Nov 26;13(12):2083. doi: 10.3390/mi13122083.
Submicron long focusing range beams are gaining attention due to their potential applications, such as in optical manipulation, high-resolution lithography and microscopy. Here, we report on the theoretical and experimental characterization of an elastomeric polydimethylsiloxane/single layer graphene (PDMS/SLG) axicon-like tunable device, able to generate diffraction-resistant submicrometric spots in a pump and probe configuration. The working principle is based on the phase change of an input Gaussian beam induced in the elastomer via the thermo-optical effect, while the heating power is produced by the optical absorption of the SLG. The phase-modified beam is transformed by an objective into a long focus with submicron diameter. Our foci reach an experimental full width at half maximum (FWHM) spot diameter of 0.59 μm at the wavelength of 405 nm, with the FWHM length of the focal line greater than 90 μm. Moreover, the length of the focal line and the diameter of the focus can be easily tuned by varying the pump power. The proposed thermo-optical device can thus be useful for the simple and cheap improvement of the spatial resolution on long focus lines.
亚微米长聚焦范围光束因其潜在应用而受到关注，例如在光学操纵、高分辨率光刻和显微镜技术中。在此，我们报告了一种弹性聚二甲基硅氧烷/单层石墨烯（PDMS/SLG）类轴棱锥可调谐器件的理论和实验表征，该器件能够在泵浦和探测配置中产生抗衍射的亚微米级光斑。其工作原理基于通过热光效应在弹性体中诱导输入高斯光束的相位变化，而加热功率由SLG的光吸收产生。经相位调制的光束通过物镜转换为具有亚微米直径的长焦点。在405nm波长下，我们的焦点实验半高宽（FWHM）光斑直径达到0.59μm，焦线的FWHM长度大于90μm。此外，通过改变泵浦功率可以轻松调节焦线的长度和焦点的直径。因此，所提出的热光器件对于简单且廉价地提高长焦线上的空间分辨率可能是有用的。
