Research And Design Of Dual-laser Synchronization Control System Based On FPGA

Transient absorption spectra developed from a research for excited state and its changes of intermediate technology since the sixties. It includes the technology of pulse radiolysis and laser flash photolysis. Pulse radiolysis is effective way for the research of short-lived excited states and intermediates of structure and movement. Laser flash photolysis is also known as time-resolved laser flash spectroscopy, it is an effective method of the research of the photochemical process and the short-lived excited state intermediates of the structure and movement. The light may be composed of various parts of the system to absorb with different pulse radiolysis. In order to study molecular targets in the course of excitation of the response ,we can select the band of no significant absorption of solvent to deal with the absorption. But solvent absorbs most of the radiation in pulse radiolysis.The paper proposes one kind of use of lasers to generate a supercontinuum white light, as a Survey light. System uses two nanosecond lasers as Survey light and the pump light source. The disturbance of fluorescence is very little. The signal to noise ratio has also been improved. But the main problem is the synchronization of the laser.The rapid development of programmable logic device technology and EDA technology increases the application of flexibility and convenience, and makes the cost more lower, the programmable logic device will be widely applied to a variety of systems.In this paper proposes one kind of dual-laser synchronization system based on programmable logic device. Dual-laser synchronization control system for transient absorption experiments is designed by using field programmable gate array technology. The system is composed of Femtosecond Laser Ti: Sappire, nanosecond laser Nd: YAG, PC, CCD, and monochromator. Dual-laser delay controller is divided into four modules: the delay signal generator module, and PC computer interface module, phase-locked loop control module and display module. Delayed signal generator module is used to produce laser trigger pulse signal, PC computer interface module connected the system and PC, phase-locked loop module provides system clock and display module is used to display delay time.Experimental system is designed to meet our requirements of specific control of femtosecond lasers and Nd: YAG laser synchronization. The 20Hz sync signal comes from femtosecond laser is divided to 10Hz to trigger monochromator and generates Nd: YAG the Lamp trigger signals, Q-Switch trigger signals. The design of the control system integrates all the control circuits and design dedicated PC interfaces, and it improves the stability of exchanging data and reduces cost of experimental system. The system based on programmable system-on-chip provides great convenience to upgrade. The system is flexible and has broad application prospects.The options of development platform in System:1. The choice of tools for the EDAAltera's EDA development platform QuartusⅡis used to develop the system.2. The choice of hardware description languageI use top-down design idea based on Verilog HDL to design the system.3. options of computer control platformThe host computer interface is designed based on NI's LABVIEW8.0The FPGA is Altera's CycloneⅡseries FPGA EP2C35F672C6, and it is configured by the use of active configuration EPCS16 chip. FPGA gives control and synchronization signals to configure the chip, and the configuration data is sent to the download cable to download. The framework of EPCS16 based on the design of efficient, and its cost is very low.This paper introduced the dual-laser synchronization control system in the nanosecond laser-pumped detection system, and introduces the principle of the various functional modules and design idea. And then the output of the controller of trigger signals is measured. We can set up our own systems by increasing or decreasing the control signal and also flexibly sets time delay adjustment range for the practical application. Programmable logic device wsa applied to the system may be one of the development direction of the experimental system。...