Generation of 480 nm picosecond pulses for ultrafast excitation of Rydberg atoms.

Atoms in Rydberg states are an important building block for emerging quantum technologies. While excitation to Rydberg orbitals is typically achieved in more than tens of nanoseconds, the physical limit is in fact much faster, at the ten picoseconds level. Here, we tackle such ultrafast Rydberg excitation of a rubidium atom by designing a dedicated pulsed laser system generating 480 nm pulses of 10 ps duration. In particular, we improved upon our previous design by using an injection-seeded optical parametric amplifier (OPA) to obtain a stable pulsed energy, decreasing the fluctuation from 30 to 6%. We then succeeded in ultrafast excitation of Rydberg atoms with excitation probability of ∼90%, not limited anymore by energy fluctuation but rather by the atomic state preparation, addressable in future works. This achievement broadens the range of applications of Rydberg atoms.