Recently, Professor Chen Jingbiao's team from the School of Electronics, Peking University, achieved key innovations in researching the core laser source technology of the Rydberg Atomic Receiver. The related research paper "External CavityDiode Laser at 509 nm for Cs RydbergAtoms" was officially published in the Journal of Applied Physics, a journal of applied physics under the American Institute of Physics (AIP), marking that the team's research results in the field of special laser light sources for quantum precision measurements have been highly recognized by the international applied physics community.
Absolute Rydberg atoms are the core carrier in fields such as quantum precision measurement, microwave electric field detection, and atomic radar. The 509nm laser is the key light source to realize two-photon excitation of absolute Rydberg atoms. Traditional frequency-doubled laser solutions have shortcomings such as large systems, high costs, and insufficient stability. Commercial external cavity lasers in the same wavelength band are difficult to meet the strict specifications of narrow linewidth, wide mode-hop-free tuning, and high stability at the same time, which restricts the miniaturization and practicalization of the Rydberg atomic radar system. In response to the above-mentioned industry pain points, the team successfully developed a high-performance 509nm grating external cavity semiconductor laser based on the Littrow configuration.
Optical equipment. Through customized GaN-based laser chips, low-noise circuit design, 2mK-level high-precision temperature control and forward feedback technology optimization, multiple core performance breakthroughs have been achieved: the laser linewidth reaches 30.0±0.4kHz, reaching the international advanced level of similar devices with the same structure. ; The mode-hopping-free tuning range is up to 152pm (176GHz), and the frequency sweep rate is up to 57.6GHz/ms, which can meet the rapid frequency hopping requirements of radar receivers; the wavelength fluctuation of free operation is less than 1pm in 2.5 hours, and the output power is 5.08mW.
The system has outstanding advantages such as compact structure, good mechanical stability, and controllable cost.
Beat frequency data (black dots) and Lorentz fitting curve (red curve) of two identical 509nm external cavity semiconductor lasers. The beat frequency linewidth is 42kHz, and the linewidth of a single laser system is 30.0±0.4kHz. This achievement is highly adapted to the technical requirements of the indestructible Rydberg atom receiver, and provides a high-performance core light source solution for applications such as quantum precision measurement, microwave sensing, and communication detection integration based on Rydberg atoms, and effectively promotes the transformation of related fields from laboratory research to engineering and industrialization.
Chen Jingbiao's team has long been engaged in research on quantum electronics, precision measurement laser technology and quantum sensing core devices. This achievement is another important innovation for the team in the field of key quantum precision measurement devices. In the future, the team will continue to focus on national strategic needs, deepen core technology research and achievement transformation, and provide solid technical support for the high-quality development of my country's quantum technology and the realization of high-level scientific and technological self-reliance.
