Pulse control of frequency and width for a real-time independently adjustable laser source

Author(s):  
Zhiwei Yang ◽  
Xu Wu ◽  
Deqin Ouyang ◽  
Encheng Zhang ◽  
Huibin Sun ◽  
...  
Keyword(s):  
2020 ◽  
Vol 20 ◽  
pp. 100204
Author(s):  
Sang Min Park ◽  
Do Yeon Kim ◽  
Soon-Woo Cho ◽  
Beop-Min Kim ◽  
Tae Geol Lee ◽  
...  

Sensors ◽  
2019 ◽  
Vol 19 (20) ◽  
pp. 4587 ◽  
Author(s):  
Yindi Cai ◽  
Baokai Feng ◽  
Qi Sang ◽  
Kuang-Chao Fan

A low-cost miniature homodyne interferometer (MHI) with self-wavelength correction and self-wavelength stabilization is proposed for long-stroke micro/nano positioning stage metrology. In this interferometer, the displacement measurement is based on the analysis of homodyne interferometer fringe pattern. In order to miniaturize the interferometer size, a low-cost and small-sized laser diode is adopted as the laser source. The accuracy of the laser diode wavelength is real-time corrected by the proposed wavelength corrector using a modified wavelength calculation equation. The variation of the laser diode wavelength is suppressed by a real-time wavelength stabilizer, which is based on the principle of laser beam drift compensation and the principle of automatic temperature control. The optical configuration of the proposed MHI is proposed. The methods of displacement measurement, wavelength correction, and wavelength stabilization are depicted in detail. A laboratory-built prototype of the MHI is constructed, and experiments are carried out to demonstrate the feasibility of the proposed wavelength correction and stabilization methods.


Author(s):  
Zhaoqing Wang ◽  
Harry H. Cheng ◽  
Stephen S. Nestinger ◽  
Benjamin D. Shaw ◽  
Joe Palen

A real-time architecture for a highway vehicle detection system is presented in the article. The Laser Based Detection System (LBDS), focused on helping the Intelligent Transportation System (ITS), measures a key quantitative parameter of vehicles moving across a link of highway, namely, travel time. Travel time is based upon the identifying and reidentifying vehicles at various points on the highway. This article provides a method to collect real-time signals from an active laser source in the LBDS and calculate vehicle parameters using a standard computer. A method of message exchange between a real-time kernel process, for real-time data acquisition, and a user space process, for computing and displaying, is given under the RTLinux environment. Experimental results from field tests have shown that the application of the real-time architecture to the LBDS provides speeds deterministically.


2009 ◽  
Vol 29 (2) ◽  
pp. 437-442
Author(s):  
梁迅 Liang Xun ◽  
姚琼 Yao Qiong ◽  
胡永明 Hu Yongming ◽  
熊水东 Xiong Shuidong ◽  
胡正良 Hu Zhengliang ◽  
...  

Author(s):  
Cagla Ozsoy ◽  
Vijitha Periyasamy ◽  
Michael Reiss ◽  
Xosé Luís Deán-Ben ◽  
Daniel Razansky

2020 ◽  
Vol 70 (3) ◽  
pp. 285-291
Author(s):  
Rajeev K. Dohare ◽  
Mainuddin Siddique ◽  
Gaurav Singhal

The medium gas lasers involves in-situ generation of the lasing medium, hence are associated with several complex processes including mixing of pumping and lasing species, energy exchange between the species, heat generation during reaction and its influence on the flow domain to list a few. Thus, the characterisation of lasing medium, condition of operation of individual critical subsystems and corresponding phenomenon thereof is essential in real time. It is here that a customised data acquisition and analysis system (DAAS) plays a key role. The paper dwells on the realisation of a customised hybrid DAAS with a master-slave architecture, which is portable and provides remote system operation. The noteworthy aspects of the developed DAAS include capability to handle close to 150 channels [64 analog input, 64 digital output, 5 analog output and 17 digital input] simultaneously with varied sampling rates requirement ranging from 100 samples/s to 200 k samples/s, modularity in design enabling scalability. Further, the efficacy of the developed DAAS has been tested by conducting several real time experiments with an existing chemical oxygen iodine laser source with a mass flow rate of 2.3 moles.s-1 both from close ranges and at line of sight remote distances of up to 80 m and nearly 35 m with obstacles.


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