Laser Stabilisation for two-photon Rydberg transitions
Rubidium atoms are excited to Rydberg states using a two-photon transition from the 5S1/2 ground state. First the atom is excited from to the 5P3/2 excited state using a 780nm DL100 laser, followed by a second transition at 480nm from 5P3/2 to nS or nD Rydberg states using a high power frequency doubled TA\DL-SHG 110 system.
To stabilise the lasers to the two-photon transition, the 780nm probe laser is locked to a modulation transfer signal generated using an EOM with a 10MHz modulation frequency. Having locked the probe beam, the 480nm laser is then locked using the EIT signal from a thermal cell.
Currently there are two systemsFor the experiments performed using these laser systems a key parameter is the relative linewidth of the two-photon transition. In order to reduce this, the lasers are locked using a Fast Analog Linewidth Control (FALC) module which uses very fast current feedback to make corrections to the linewidth with a bandwidth ~10 MHz alongside a slow piezo feedback to give larger frequency correction.
in operation, which are described below:
- DL100-PRO 780nm Probe laser
- TA\DL-SHG 110 with DL-MOD laser head
- Both lasers use prototype FALC modules
- DL100-MOD 780nm probe laser
- TA\DL-SHG 110 with DL-PRO laser head
- Both lasers use new FALC modules