Study Of Radio Frequency Circuit And System For Single Photon Detection

A photon is defined as the single-mode excited state of the quantized electromagnetic field.The energy of a single photon in the mode k of the quantized electromagnetic field can be expressed by its frequency ? and Planck's constant h,which is h?.In other words,a singlephoton state is one for which the photon-number statistics have a mean value of one and a variance of zero.Single-photon detection technology plays an important role in the fields of national defense,national security,and quantum communications.It is a technological crucial opportunity that our country urgently needs to seize,so it is of great significance to research on this topic.The single-photon detection in this paper is mainly for the weak light from visible light to near-infrared and microwave single-photon in the microwave frequency band with lower energy.Firstly,the basic knowledge of radio frequency circuits and systems is analyzed and summarized,mainly including transmission line theory and microwave network basic knowledge,Smith chart,impedance matching and circuit debugging,vector network analyzer principle and testing.Then,we explain the research progress of microwave dynamic inductance detectors and cryogenic low-noise amplifiers,including their principles,design,preparation and testing.Analogous to the radio frequency transceiver index analysis method,we realize the index analysis of the radio frequency signal measurement system,mainly including the noise figure,Gain,input and output power of 1 d B compression point,sensitivity,etc..Combined with the weak radio frequency signal measurement system in the laboratory,the sensitivity analysis method for different temperature zones is proposed,which provides a theoretical basis for the design of a high-sensitivity radio frequency signal measurement system and reveals the realization of high sensitivity.The essence of high sensitivity is the extremely low test environment temperature and the narrowband response of the detector.Finally,based on the prototype of Wilkinson power divider,commercial electromagnetic simulation software HFSS is used to design a coplanar waveguide superconducting microwave power divider with a center frequency of 5 GHz and an equal power division ratio.The principle,design,preparation and testing methods of the Josephson parametric amplifier is summarized,and then we propose a microwave single-photon detection system that requires higher energy resolution.The main research work is to complete the design and optimization of the low-light detection system based on the microwave dynamic inductance detector and the microwave single-photon detection system based on the Josephson parametric amplifier.The research results are as follows:(1)The sensitivity analysis method for different temperature zones is proposed,and the sensitivity of the measurement system in the 20 m K temperature zone is analyzed to reach a level of about-140 d Bm,which provides a theoretical basis for weak light detection from visible light to near-infrared.The designed and optimized high-sensitivity radio frequency signal measurement system provides hardware conditions for low-light detection.(2)The design,fabrication and testing of a coplanar waveguide superconducting microwave power divider with an operating frequency of 5?5.5 GHz is completed.This work can be extended to the design and fabrication of other superconducting microwave passive devices.Combined with the Josephson parametric amplifier,we put forward a design scheme of microwave single-photon detection system.