Real-time tracing FPGA circuit system of the virtual signals from thermal motion simulations in optical tweezers. (November 2020)

• Record Type: Journal Article
• Authors: Hu, Zhanming; Han, Xiang; Chen, Zhijie; Xiong, Wei; Chen, Xinlin; Xiao, Guangzong; Yang, Kaiyong; Luo, Hui
• Is Part Of: Journal of physics. Volume 1684(2020)
• Publication Date: 2020-11
• Subjects: Physics -- Congresses; 530.5
• DOI: 10.1088/1742-6596/1684/1/012146
• Languages: English
• ISSNs: 1742-6588

Abstract

Abstract: Optically trapped nanospheres are demonstrated capable of atto-Newton force sensing, where its experiment need to control the modulation voltages of the laser power according to the positions of the trapped nanosphere in high speed. In this paper, position fluctuations of the trapping nanospheres due to thermal motions are simulated using Monte-Carlo method and finite difference method. Equal-scale amplified transformations of those position sequences are generated as the discrete voltage signal of the virtual position detector. A high-speed digital incremental PID(Proportion-Integration-Differentiation) control system is developed by a low-cost FPGA circuit system, which can generate feedback voltage signals correspondingly. The responsive signal frequency is up to 1MHz with a time delay of 0.3μs and quite high amplitude stability. It is validated to integrate the virtual position detector and the PID feedback system into a low-cost semi-physical system, which can test various feedback cooling mechanisms for the complex systems of optical tweezers in vacuum. It will be a further step relative to the pure simulations in digital computers and provide references for the development of optical tweezers in vacuum.