Multi-beam Photon Counting Laser Ranging

Single photon detector is the important quantum device of the subjects of quantum control, laser remote sensing and ultra-sensitive spectroscopy, and it is basement of the cutting-edge technology. But in practical application, the traditional detector cannot receive the wild range signal because of the low counting saturation. Limited to the existing technology, the measurement speed is slow and is not good to fast measuring.A new method of laser ranging was demonstrated by employing a dual-mode photon detector to meet the large dynamic range of the echo photons. A single detector based on Si APD was operated between the linear mode and the Geiger mode by adjusting the DC bias voltage on APD, and the detection dynamic range of the average photon number was measured to be 100-105 per pulse. The 30m indoor and 500m outdoor ranging experiments were carried out in linear mode and Geiger mode, respectively. The echo signal was recorded by the TCSPC equipment to investigate the ranging time characteristics in the dual-mode ranging system. The results indicated that the ranging system with a single detector could conveniently switch the operation modes to adopt different ranging distances and environmental conditions due the large dynamic range detection. As the key parameters of the system, the measurement accuracy and the detection background noise were further studied while the operation modes were switching under different bias voltages on APD.Based on the dual mode detector we proposed a method of multi beam photon counting laser ranging. We used the Dammann grating to split the beam and received the signal by fiber array. Finally we processed data by the method of time correlated single photon counting and test the crosstalk of the fiber array. By the multichannel single photon detector we improved the sensibility and reduced the laser power and realize the 10 channel photon counting laser ranging in the range of 30m.