1.6 GHz Frequency Scanning of a 482 nm Laser Stabilized Using Electromagnetically Induced Transparency

We propose a method to continuously frequency shift a target laser that is frequency stabilized by a reference laser, which is several hundreds of nanometers detuned. We demonstrate the technique using the 5S
_1/2
→ 5P
_3/2
→ 29D
_5/2
Rydberg transition in
⁸⁷
Rb vapor and lock the 482 nm target laser to the 780 nm reference laser using the cascaded electromagnetically induced transparency signal. The stabilized frequency of the target laser can be shifted by about 1.6 GHz by phase modulating the reference laser using a waveguide-type electro-optical modulator. This simple method for stable frequency shifting can be used in atomic or molecular physics experiments that require a laser frequency scanning range on the order of several GHz.