High-Performance Digital Lock-In Amplifier Module Based on an Open-Source Red Pitaya Platform: Implementation and Applications

A lock-in amplifier (LIA) is an instrument that can extract weak signals from extremely noisy environments, and it is widely used in various precision measurement fields. However, there are still challenges in lock-in techniques in experiments that require high-frequency or multiple lock-in channels, such as high-frequency vibration detection and experiments with quantum sensors. The direct use of commercial LIAs will result in high experimental costs. Herein, a high-performance digital LIA module based on an open-source Red Pitaya (RP) platform is constructed. The quantitative description of the demodulation results, efficient data transfer method, and the development of the automated measurement functions in experiments are carried out in this module. As demonstrations, the phase difference and thermal noise measurements are conducted using the module. The research on temperature sensing with the frequency shift of quartz crystals and semiconductor doping concentration measurements has also been implemented. These demonstrations show that the digital lock-in module has good application prospects.