Rydberg atoms have electron(s) with a large principle quantum number, n. Using a technique known as Electromagnetically Induced Transparency (EIT) we shown that it is possible to probe these states. For more information see here
We have been recently exploiting this technique in a number of different ways. Rydberg states have a high polarisability which means that by using a few volts, we can modify the optical propeties of media. In our recent paper we coupled together a Lambda system and a ladder system to combine long-lived ground-state superpositions with the strongly interacting character of Rydberg states.
Motivated by the desire to perform a quantum gate in the 3D Optical Lattice it is necessary to be able to have control over the state of the qubits. This is done using Rabi pulses. An Electro-Optic modulator is used to add sidebands to a diode laser running at 780 nm. The separation in frequency of each sideband from the carrier is 6.8 GHz -the hyperfine splitting in the ground state of 87Rb.