LabVIEW-based Data Acquisition And Control Analysis System For Standing Wave Cavity

In recent years,optical resonant cavity has become one of the indispensable experimental devices in the research of modern optics,especially laser optics,quantum optics and other fields.Therefore,it is especially important to master the working principle of resonant cavities and cavity adjustment techniques.However,with the development of science and technology,in order to improve the precision and accuracy of instruments,many instruments involving resonant cavities have been developed into closed integrated type,which makes it difficult for postgraduates to have the opportunity to personally contact and debug resonant cavities and master their working principles profoundly,while most of the institutions of higher education with physics and optoelectronics specialties also lack relevant experimental teaching about resonant cavity adjustment.Therefore,the design and development of a set of simple and convenient experimental system of standing wave cavity has important scientific research and practical application value.With the rapid development of digitalization and intelligence in society,the combination of virtual instrumentation and measurement control has become an important trend in experimental teaching and research needs.Based on this,this study applies the virtual instrumentation technology to the control and measurement of the standing wave cavity experimental system.Based on the virtual instrumentation Lab VIEW software platform,combined with hardware USB-6216 data acquisition card and CCD with USB data transmission and other hardware,this paper designs a cavity length adjustable standing wave cavity data acquisition and control analysis system,the research content is mainly divided into the following four parts:Part I:A brief introduction to the research background of optical resonant cavities,virtual instrument-aided experimental measurements,the development status of relevant aspects at home and abroad,and the practical significance of the subject.Part II:The experimental setup of standing wave cavity with adjustable cavity length is constructed.The F-P cavity interference theory and the three experimental parameters reflecting the single longitudinal mode resonance characteristics are explained,and the waist spot mode matching method of the standing wave cavity is explained.Based on this,the overall layout of the experimental setup is designed and the operation steps for adjusting the single mode operation of the standing wave cavity are described in detail.Part III:Development of a LabVIEW-based virtual instrumentation system.The working principles of each physical instrument and the key techniques of data acquisition are explained,and the overall design of the system is proposed.The detailed design process of functional modules such as data acquisition,data storage and playback,parameter measurement,waveform summing/subtraction,spectrum analysis,digital filtering and beam quality analysis is given,and the block diagram of the design procedure is shown.Part IV:The data acquisition and control analysis functions of the software are realised by making comparisons using real instrumentation and virtual instrumentation system measurements,selecting the virtual instrumentation system to measure the transmission spectrum,reflection spectrum and spot pattern of the single mode operation of the standing wave cavity and using it for theoretical data comparison.The cavity length is continuously varied from 50 mm to 90 mm,the free spectral region of the cavity ranges from 1600 MHz to 2900 MHz,the cavity mode linewidth ranges from 7 MHz to 12 MHz,the fineness is maintained at around 237 and the measured values are basically in agreement with the theoretical values.