Free-space optical communication with perfect optical vortex beams multiplexing

Author(s):

Wei Shao and Sujuan Huang and Xianpeng Liu and Musheng Chen

Abstract:

“We demonstrate a 2-channel orbital angular momentum (OAM) multiplexed free space optical communication (FSO) link using perfect optical vortex (POV) beams. POV beams are able to be transmitted coaxially over than 1m with the assistance of a microscope objective and normal lens. 16QAM-OFDM signals are used to measure the performance, which is also compared with the FSO link based on Laguerre–Gaussian (LG) vortex beams multiplexing in the same experimental environment. The results show that, the FSO link employing POVs multiplexing can bring a better performance to the system, which can always obtain a lower BER under the same received power; The using of POVs as carriers greatly reduces the systems’ sensitivity to the change of OAM topological charge numbers; And the constant diameter of POVs is also improve the versatility of the optical
devices of different channels in the system.”

Link to Publications Page

Publication: Optics Communications

Issue/Year/DOI: Optics Communications Volume 427, pp. 545-550
DOI: 10.1016/j.optcom.2018.06.079

Aberration correction for improving the image quality in STED microscopy using the genetic algorithm

Author(s):

Luwei Wang, Wei Yan, Runze Li, Xiaoyu Weng, Jia Zhang, Zhigang Yang, Liwei Liu, Tong Ye and Junle Qu

Abstract:

“With a purely optical modulation of fluorescent behaviors, stimulated emission depletion (STED) microscopy allows for far-field imaging with a diffraction-unlimited resolution in theory. The performance of STED microscopy is affected by many factors, of which aberrations induced by the optical system and biological samples can distort the wave front of the depletion beam at the focal plane to greatly deteriorate the spatial resolution and the image contrast. Therefore, aberration correction is imperative for STED imaging, especially for imaging thick specimens. Here, we present a wave front compensation approach based on the genetic algorithm (GA) to restore the distorted laser wave front for improving the quality of STED images. After performing aberration correction on two types of zebrafish samples, the signal intensity and the imaging resolution of STED images were both improved, where the thicknesses were 24 μm and 100 μm in the zebrafish retina sample and the zebrafish embryo sample, respectively. The results showed that the GA-based wave front compensation approach has the capability of correction for both system-induced and sample-induced aberrations. The elimination of aberrations can prompt STED imaging in deep tissues; therefore, STED microscopy can be expected to play an increasingly important role in super-resolution imaging related to the scientific research in biological fields.”

Link to Publications Page

Publication: Nanophotonics Volume 7: Issue 12

Issue/Year/DOI: Volume 7: Issue 12
DOI: 10.1515/nanoph-2018-0133