Investigation On Preparation And Measurement Of Room-temperature Single Photon Source

With the rapid development of quantum information technology such as quantum communication and quantum computation, single photon source(SPS) has gradually become a research hotspot. However, most of the current methods to produce SPS are more complex and with harsh technical requirements, for instance, cryogenic equipment is usually required, which all limit the application of the SPS. In this paper, the SPS preparation method under the condition of room temperature is mainly studied, and the photons from the source are monitored by establishing a standard test system. The main contents and conclusions of this paper are as follows:Firstly, current various SPS preparation methods are introduced, including laser attenuation method, on-demand SPS preparation method based on special materials such as atoms, quantum dots and crystal defects, and entangled photon sources method using nonlinear technology, of which the advantages and shortcomings are analyzed. Furthermore, in this paper, the experimental principle of HBT test system is introduced in detail, since HBT coincidence counting system is the standard instrument to evaluate the performance of the SPS.Secondly, precise amplifier module, discrimination module and counting module are chosen and purchased to set up test experimental system, with which the Photomultiplier tube(PMT, type:R105) frequency response limit is measured. Action to improve PMT is also taken to improve the anti-interference ability and reduce the dark noise. By detecting the single photons with the improved PMT, an accurate pulse-height distribution diagram is gained, of which the curve is more accurate and reasonable compared with the previous results.Finally, a highly stable laser source is selected, from which continuous light is precisely attenuated three times with high magnification to produce single photons. Through utilizing low noise single photon detectors (dark count rate<200cps), a HBT coincidence counting test experiment is conducted, and the total number spectrum distribution of single photons is gained.Analysis shows that scheme based the laser attenuation in this paper is more easily achieved at room temperature, and produced single photons have more noticeable stochastic behavior. In addition, because of applying the laser source with high quality, stability of the single photon source is more advantageous. The conclusion of this paper provides important reference value to the research on quantum communication.