High-power picosecond 355 nm laser based on La₂CaB₁₀O₁₉ crystal

Ultrafast, high repetition rate, ultraviolet, fiber-laser-based source: application towards Yb+ fast quantum-logic

Trapped ions are one of the most promising approaches for the realization of a universal quantum computer. Faster quantum logic gates could dramatically improve the performance of trapped-ion quantum computers, and require the development of suitable high repetition rate pulsed lasers. Here we report on a robust frequency upconverted fiber laser based source, able to deliver 2.5 ps ultraviolet (UV) pulses at a stabilized repetition rate of 300.00000 MHz with an average power of 190 mW. The laser wavelength is resonant with the strong transition in Ytterbium (Yb⁺) at 369.53 nm and its repetition rate can be scaled up using high harmonic mode locking. We show that our source can produce arbitrary pulse patterns using a programmable pulse pattern generator and fast modulating components. Finally, simulations demonstrate that our laser is capable of performing resonant, temperature-insensitive, two-qubit quantum logic gates on trapped Yb⁺ ions faster than the trap period and with fidelity above 99%.

High average power third harmonic generation at 355 nm with K3B6O10Br crystal

We demonstrate a nanosecond 355 nm laser by third harmonic generation of an Nd: YAG laser with a 4 × 4 × 13.3 mm³ type I cut K₃B₆O₁₀Br crystal for the first time. The maximum average power of 19.3 W is achieved with the corresponding conversion efficiency of 16.3% and the maximum conversion efficiency of 18.3% is recorded when the 355 nm average power is 15.8W. In addition, several nonlinear optical parameters including the angle and temperature bandwidths at third harmonic generation are also investigated.

Stable, high-power, Yb-fiber-based, picosecond ultraviolet generation at 355 nm using BiB3O6

We report a stable, high-power, high-repetition-rate, picosecond ultraviolet (UV) source at 355 nm based on single-pass sum-frequency generation of a mode-locked Yb-fiber laser at 1064 nm in the nonlinear crystal BiB3O6. By performing single-pass second-harmonic generation (SHG) in a 30-mm-long LiB3O5 crystal, up to 9.1 W of average green power at 532 nm is obtained at a single-pass SHG efficiency of 54%. The generated green pulses have a duration of 16.2 ps at a repetition rate of 79.5 MHz, with a passive power stability better than 0.5% rms and a pointing stability <12  μrad over 1 h, in high beam quality. The green radiation is then sum-frequency-mixed with the fundamental in a 10-mm-long BiB3O6 crystal, providing as much as 1.2 W of average UV power, at an infrared-to-UV conversion efficiency of 7.2%, with a passive power stability better than 0.4% rms over 3 h and a pointing stability <45  μrad over 1 h, in TEM00 spatial profile.