Research On Spot Position Measurement Of Pulsed Light Based On One-dimensional PSD

The laser spot position measurement plays an important role in the laser tracking,the laser communication and other laser technologies.Among them,the technology of the continuous light spot position measurement has become increasingly mature,but the research on the technology of the pulsed light spot position measurement is largely nonlinear.It causes difficulties in linear measurement of the spot position.However,because the pulsed light has a series of outstanding advantages compared with the continuous light,and it has more and more extensive application prospects in many fields in the future,the research on the technology of the pulsed light spot position measurement has attracted extensive attention from domestic and foreign researchers.The research work of this thesis is mainly to correct the nonlinear response of the one-dimensional PSD to the pulsed light and reduce the measurement error of the spot position.The research in this thesis provides a practical idea and method for the precise measurement of the pulsed light spot position.The main content of this article is divided into three parts,as follows:First,numerically simulate the response law of continuous light incident on the photosensitive surface at different positions on the 1mm×6mm one-dimensional PSD at equal intervals,and fit the simulated response steady-state value to obtain the steady-state response of the one-dimensional PSD to the continuous light.Based on the mathematical law that the value changes with the incident point,the influence of continuous light incident of different powers on the response law of one-dimensional PSD is discussed.Secondly,the continuous light in the above process is replaced by pulsed light and numerical simulation is carried out.Fitting the response peak after numerical simulation can obtain the mathematical law that the response peak of one-dimensional PSD to pulsed light varies with the incident point.On this basis The influence of pulsed light of different power and different pulse width on the response law is discussed separately.Finally,a non-linear correction method is proposed.By analyzing the relationship between the response law of one-dimensional PSD to continuous light and pulsed light at equal intervals,the response law of one-dimensional PSD to pulsed light is transformed to that of continuous light.The response law realizes the correction of non-linearity.And the method is proved to be feasible theoretically and experimentally.The main research results of this paper are:a method for correcting the nonlinear response of one-dimensional PSD to pulsed laser incidence is proposed.Theoretically simulate the response peaks of pulsed light with different pulse widths incident on the photosensitive surface at different positions on a 1×6mm one-dimensional PSD at equal intervals and the results after nonlinear correction.When the pulsed light with a pulse width of 5ns is incident,After nonlinear correction,the position information of the light spot can be measured linearly in the interval of[-2,2]mm,and the measurement error can be reduced by 0.74678 mm at the maximum,which is reduced by 80%to 90%;as the pulse width continues Increasing,the range of linearly measuring the position of the pulsed light spot will gradually widen;while the light of different optical powers incident on different positions of the one-dimensional PSD has basically no effect on its response law.In the experiment,the incident position of pulsed light with a pulse width of 50ns was measured,and the measurement data was corrected by a nonlinear formula.It was obtained that within a certain range,accurate measurement of the spot position can be achieved,and the maximum position error can be reduced by 0.25039 mm,reduced by 70%to 90%,and the experimental results are in good agreement with the theoretical model.