WANG Zhao-hua1, WANG Lei1, LI Bai-hong1, LI Jun2, LI Yong-fang1*
(1 College of Physics and Information Technology, Shaanxi Normal University, Xi′an 710062, Shaanxi, China; 2 National Lab of Radar Signal Processing, Xidian University, Xi′an 710071, Shaanxi, China)
Abstract:
Based on the principle of quantum coherent,the entangled biphoton state with in frequency-coincident pumped by spontaneous type-Ⅱ parametric down-conversion is analyzed. The quantum coherent properties of this system are researched and compared with that of the frequency-different biphoton. The results showed that as increasing the pump band-width, the asymmetry of the phase-matching function of the frequency-different biphoton state is increased, and then the coherence of entangled biphoton is diminished. However, the phase-matching function of the frequency-coincident biphoton state is still symmetric, and the coherence of entangled biphoton is best.
KeyWords:
frequency-coincident biphoton state； second-order correlation function; quantum interference; pulse laser
