  Atoms in Rydberg states are an important building block for emerging quantum
technologies. While the excitation to the Rydberg orbitals are 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 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.
