Development of a high-power deep-ultraviolet continuous-wave coherent light source for laser cooling of silicon atoms

Sum-frequency mixing of radiation from two extended-cavity laser diodes using a doubly resonant external cavity for laser cooling of trapped ytterbium ions

Over 100 μW of continuous-wave tunable ultraviolet radiation at 370 nm is generated by the sum-frequency mixing of radiation from two extended-cavity laser diodes having powers of 60 mW at 822 nm and 8 mW at 671 nm in a lithium iodate crystal. The crystal is placed in an external cavity that enhances the powers of two fundamental beams simultaneously by approximately 40. This light source is successfully applied to the laser cooling of trapped ytterbium ions.

Fine frequency tuning in sum-frequency generation of continuous-wave single-frequency coherent light at 252 nm with dual-wavelength enhancement

Fine frequency tuning of the deep-ultraviolet single-mode coherent light at 252 nm was conducted through the PID feedback system automatically by changing the temperature of a beta-BaB(2)O(4) (BBO) crystal in a doubly resonant external cavity for the sum-frequency mixing of 373 and 780 nm light. The temperature-dependent frequency tuning rate is 19.3 MHzK(-1), which is sufficiently fine to realize the laser cooling of neutral silicon atoms because the natural width of the laser cooling transition is 28.8 MHz.

Efficient sum-frequency generation of continuous-wave single-frequency coherent light at 252 nm with dual wavelength enhancement

Highly efficient frequency conversions were conducted to obtain deep-ultraviolet single-mode coherent light by use of two-stage external cavities. A power of 154 mW at approximately 252 nm was obtained with a conversion efficiency of more than 8% by doubly resonant sum-frequency mixing of 373-nm light from the first-stage conversion and 780-nm light from a single-mode Ti:sapphire laser. The output performance of the deep-ultraviolet light source is sufficient for use in the laser cooling of neutral silicon atoms.

Efficient frequency doubling of 1-W continuous-wave Ti:sapphire laser with a robust high-finesse external cavity

We demonstrated an intrinsic conversion efficiency of 56% from the input fundamental power to the generated second-harmonic power. The second-harmonic power of 581 mW was obtained from the external cavity with a LiB3O5 crystal through the frequency doubling of a 1.17-W Ti:sapphire laser at 746 nm, when the finesse of the robust external cavity was 260.

All-solid-state tunable continuous-wave ultraviolet source with high spectral purity and frequency stability

We present a novel approach for the generation of higly frequency-stable, widely tunable, single-frequency cw UV light that is suitable for high-resolution spectroscopy. Sum-frequency generation (SFG) of two solid-state sources with a single cavity resonant for both fundamental waves is employed. Using a highly stable, narrow-linewidth frequency-doubled cw Nd:YAG laser as a master laser and slaving to it the SFG cavity and the other fundamental wave from a Ti:sapphire laser, we generate UV radiation of 33-mW output power around 313 nm. Alternatively, we use a diode laser instead of the Ti:sapphire laser and produce an output power of 2.1 mW at 313 nm. With both setups we obtain a continuous tunability of >15 GHz, short-term frequency fluctuations in the submegahertz range, a long-term frequency drift below 100 MHz/h, and stable operation for several hours. The theory of optimized doubly resonant SFG is also given.