Multi-photon coincidence counter based on programmable logic device

Abstract

The invention discloses a multi-photon coincidence counter based on a programmable logic device. Based on the large capacity of a DDR, the simultaneous counting of multiple coincidence types can be supported, a diversion mechanism is used to solve the problem of insufficient DDR reading and writing speeds, and the event rate of a coincidence system is improved. Moreover, through introducing pulse shaping and a synchronous clock, the generation of accidental coincidence can be inhibited dually. At the same time, pulse time delay can be dynamically adjusted, since the IO resource of an FPGA is employed, the adjustment precision reaches tens of picoseconds, and the linearity is good. The problem that the consistency may not be guaranteed in each time due to the time delay of an input signal is solved by dynamic adjustment. Moreover, a scanning mechanism is introduced, and thus in the condition of knowing single channel counting distribution, the correctness of a coincidence result can be extrapolated. In addition, a PC can know a system working state according to a state word and adjust a system parameter through the control word, thus the working flow is automated, and the robustness of the system is improved.

Description

technical field [0001] The invention relates to the field of photon counting, in particular to a multi-photon coincidence counter based on a programmable logic device. Background technique [0002] Multiphoton entanglement is a peculiar quantum phenomenon, which is an indispensable resource in the study of quantum nonlocality, quantum error correction and quantum simulation. The greater the number of photons, the greater the degree of freedom of a single photon, and the stronger the ability of the multi-photon system to process information. In the latest experimental advance, the entanglement of eight photons has been achieved. [0003] In multi-photon entanglement experiments, converting the quantum properties of entanglement into quantities that can be observed in our empirical world requires counting and counting the number of photons. Since entanglement is a many-body process, counting is coincidence counting. The function of the coincidence counter is to judge and cou...

AI Technical Summary

Problems solved by technology

[0007] However, Gaertner's scheme realizes arbitrary coincidence of eight channels, and cannot be easily extended to dozens of channels, because the type of coincidence increases exponentially with the number of channels, and the event rate will also increase accordingly. At this time, the capacity of the memory and speed will be the bottleneck

The integration and flexibility of discrete devices cannot match that of FPGAs

More importantly, the event rate of the system is 0.8MHz, the dead time is 14ns, and the data cannot be read out in real time, so it cannot meet the needs of today's experiments

[0008] At the same time, although the PARK scheme has a minimum coincidence window of 0.47ns and a maximum input frequency of 163MHz, it can only count several pre-selected coincidences at the same time due to the use of an AND gate.

When the number of channels increases to dozens, the connection of AND gates will become very complicated

Images