Entangled photon pair by SPDC and its applications

Spontaneous parametric down-conversion process (SPDC) is a nonlinear optical process in which a pump photon is automatically converted into an entangled photon pair with a lower frequency of signal and idler. SPDC is the heart of many quantum optics experiments, such as quantum cryptography, quantum computer, quantum biology, quantum metrology, as well as experiments on the fundamental laws of quantum physics. In this lecture, we will talk about photon pair generation arrangements in entanglement and its application in quantum interferometers, imaging and quantum measurements, etc.