High-power injection-locked blue laser for Rydberg atom-based sensing

A compact, high-power, and stable blue laser source is essential for Rydberg state excitation of rubidium (Rb) atoms, particularly for emerging Rydberg atom-based sensors that require portability for practical applications. In this work, we present an injection-locked laser system using blue laser diodes for both the leader and follower lasers near 480 nm, enabling efficient Rydberg state preparation of Rb and eliminating the need for nonlinear frequency-doubling. The locked follower laser delivers 263 mW of output power with a linewidth of 591(31) kHz after frequency stabilization. High-efficiency spatial mode matching between the seed light and follower laser is accomplished through a polarization-maintaining fiber, resulting in a power gain of 30.4 dB. The compact optical path design allows the laser system to occupy just 20 × 21 × 4 cm³. Such a high-power and compact injection-locked blue laser system provides a low-cost and efficient solution for Rydberg atom-based applications.