| the past two decades,with the rapid development of quantum information science in the world,optical quantum information processing has become one of the most popular research fields in the quantum information science.At present,the bottleneck of experimental research on optical quantum information processing is how to increase the number of operable entangled photons and to realize quantum storage of multiphoton entanglement,which directly affects the scalability of optical quantum information processing.The cavity-enhanced spontaneous parametric down-conversion(10MHz-100MHz)is encountered due to the too big line width of the photon pair generated by the conventional spontaneous parametric down-conversion method(100GHz-1 THz),which mismatch to the interference between independent light sources and the quantum storage based on atomic ensemble and solid-state systems.Therefore,multi-photon entanglements with narrow line width can be prepared,which solve the problem of wide line width and have the potential application value in remote quantum communication,optical quantum computing,hybrid quantum network etc.For the improvement of the number of operable quantum entangled photons,the experimentally prepared ten-photon entangled state is close to the bottleneck.If you want to greatly increase the number of entangled qubits,you must rely on the breakthrough of experimental methods.It is well known that photons have orbital angular momentum,and the quantum number characterizing the orbital angular momentum can take any integer,so that the orbital angular momentum of a single photon can form an infinite dimensional Hilbert space in principle.So far,experiments have been implemented gradually.Such as high-dimensional quantum entangled states based on orbital angular momentum and related applications.This paper is aimed at the partial research of the cavity enhanced spontaneous parameter conversion system based on photon orbital angular momentum,which is focusing on the following aspects:(1)We use phase modulation of light field and Pound-Drever-Hall(PDH)frequency stabilization control technology to achieving the stability of the Fabry-Perot(FP)interferometer;(2)Designing a Proportional-Integral-Derivative(PID)temperature control system for temperature control of quasi-phase matching of periodically poled potassium titany phosphate(PPKTP)crystals.The temperature range is between 5? and 55?.The temperature stability is controlled within 0.003?,which satisfies the temperature accuracy requirement of quasi-phase matching;(3)We made etalons by ourself,and keep the stable optical filter effect of the etalon via the PID temperature control system. |
PDF Full Text Request