Quantentechnologie

In our laboratory, we use cesium atoms, which are trapped in the optical lattices. For the practice of quantum walks, atoms must be well isolated from the noisy environment so that long decoherence time can be achieved. It has been analyzed that fluctuations of the lattice depth originated from intensity fluctuations is one mechanism of decoherence. To suppress the intensity noise of optical lattices, we implement an intensity stabilization control loop based on a field-programmable gate array (FPGA) digital platform (Keysight AIO-H3336F). With the advantages of its integratability and flexibility, the application of digital control opens more possibilities for light intensity modulation. In addition to the intensity stabilization, a feedforward control of light intensity becomes feasible with the use of digital signal processing function of FPGA. The realization of intensity feedforward control provides us with a high bandwidth of intensity modulation as well as the conveniences of creating arbitrary intensity ramp implementation. Therefore, it plays an important role in our exploration into the physics related with a time-varying optical trap depth.