480 nm激光的稳频对于实现铷原子从基态双光子相干激发到里德堡态必不可少。基于梯形构型下的电磁诱导透明现象，一种新的480 nm激光器稳频技术采用偏振谱稳频的 780 nm激光作为探测光而480 nm激光则作为耦合光，在外加偏置磁场作用下产生的双光子双色原子气体激光锁频(DAVLL)谱，将该谱信号通过比例-积分-微分电路后 反馈回480 nm激光器即可实现稳频。在频率锁定后，480 nm激光器和780 nm激光器长时间稳频的总线宽为1 MHz左右。

Frequency stabilization of a diode laser at 480 nm is crucial for coherently exciting rubidium atoms to Rydberg states. A laser frequency stabilization technique is reported based on electromagnetically induced transparency in a ladder configuration with a polarization spectrum stabilized 780 nm diode laser as the probe laser and a 480 nm laser as the coupling laser. With a uniform magnetic field, a two-photon dichroic atomic vapor laser lock (DAVLL) spectroscopy was generated. Then this spectroscopy was fed back through two proportion-integral-differential circuits to lock the 480 nm diode laser. A combined linewidth of about 1 MHz is achieved during the locking period.