Laser frequency stabilization using embedded control for atom trapping systems

We present a laser frequency stabilization technique using digital proportional-integral-derivative on a microcontroller (MCU). The system is designed to stabilize laser frequency fluctuations for high-precision cold atom-based experiments. The STM32-based MCU platform, operating at a fraction of the cost of traditional field programmable gate array-based systems, provides comparable or superior performance, demonstrating its potential as a robust and low-cost alternative for laser frequency stabilization. Our setup employs the dichroic atomic vapor laser locking technique to extract the error signal for feedback control. The performance of the locking system is thoroughly characterized through a long-term stability test, overlapping Allan deviation, noise spectral density measurement, and linewidth measurement. The achieved linewidth is 93 ± 2 kHz using the delayed self-heterodyne interferometry (DSHI) method. We have also presented the development of a high-voltage piezo driver that is capable of producing up to 150 V, suitable for many commercial piezo actuators, offering a 6 GHz mode-hop free range for our home-built external cavity diode laser. We have verified the system's stability through its application in cooling and trapping ∼1.5 × 106 cesium atoms in our laboratory.