Panoramic Single-channel Ultraviolet Imaging Detector Based On Mn-doped Quantum Dots

The space-separated dual-optical channel structure is used in most of the traditional panoramic solar-blind imaging detection techniques,which not only requires ultraviolet（UV）intensifiers and broadband cut-off filters,but also suffers from image fusion bias.In this paper,a single-channel panoramic UV imaging detector based on fluorescence wavelength down-conversion of manganese-doped quantum dots（QDs）was designed.It was a time-separated UV/Vis panoramic detection technology.The UV and visible images were obtained from the same optical path,which avoided image registration,parallax correction and so on.Firstly,the construction of this system took advantage of the fluorescence down-conversion and long fluorescence lifetime of Mn-doped core/shell Zn_xCd_1-xS:Mn/ZnS QDs.The incident light of UV signal was converted by QDs into yellow fluorescence which was sensitive for a Si-based CCD（Charge-coupled Device）.And due to the millisecond fluorescence lifetime of the yellow fluorescence,the background visible image and the UV image were obtained separately when the detector optical path was on the states of on and off.So that the detection and extraction of UV signals were realized.Secondly,the power supply circuit of the system,the minimum system circuit of the control unit,the optical switch circuit used to monitor the state of the optical path,and the key circuit used for interaction were designed and implemented in this paper.And the PCB board of the main control circuit of the system was drawn.Then,the software of the system was designed and implemented.In this paper,the microcontroller program was designed and programmed,so that when it received the optical switch signal,a pulse signal would be sent to control the CCD shooting.Thus,clear UV images and visible images were obtained at the right moment,respectively.The related functions of OpenCV were called to perform digital image processing such as filtering,binarizing,extracting the region of interest（ROI）and morphological operations on the UV image.And then the UV image was fused with the corresponding visible image and displayed.The control software of the CCD was developed twice,so that it could select different gain values and add digital processing of UV and visible images when shooting images.And based on Qt,the application program of ultraviolet imaging detector was designed,which enriched the operability of the system and improves the user experience.Finally,a prototype of a panoramic UV imager was assembled by optimizing and integrating each module of the system.The working performance and imaging effect of the prototype were tested.And after measurement,the minimum detectable power of the prototype was less than 0.01 μW/cm².