In one of our experiments, we were interested in single-photon excitation of the atoms in a degenerate Fermi gas of lithium atoms to a Rydberg state. We needed a laser at the UV wavelength of 230 nm. LEOS was able to provide us with a competitive turn-key system that delivered about 70 mW of UV through two stages of second harmonic generation starting with infrared light from an amplified diode laser system. The system was shipped in parts and a first year-graduate student was able to get it up and running in a couple of days, in large part because of the solidly engineered design. It was straightforward to lock the laser to a ULE cavity to achieve narrow linewidths for Rydberg excitation. Whenever we had questions, LEOS responded promptly. We have been running the system for about six months now without any issues and we are already studying some very interesting physics with it!

Fluorescence image of ground-state lithium atoms exhibiting significant anitferromagnetic ordering. The UV light from the LEOSolutions laser system was used to excite atoms from a single-spin species band insulator of lithium atoms in an optical lattice to a Rydberg state with a blockade radius comparable to the lattice spacing. This realizes a transverse field quantum Ising model with an antiferromagnetic ground state, where the Rydberg atoms exhibit checkerboard correlations. The Rydberg atoms were photoionized and lost before taking this fluorescence image.

Spin correlation strength vs. displacement between the sites being correlated.

We use a 4th harmonic laser system from LEOS for angle resolved photoemission (ARPES). This system allows us to do very challenging high-resolution ARPES experiments on micron-sized single crystals and has quickly evolved into one of our favorite research instruments. It can be safely operated by non-specialists, provides a high UV power with good beam characteristics and works reliably even in the noisy environment of a standard UHV lab with permanently running mechanical pumps.

Phys. Rev. B, 87, 075113
Phys. Rev. X, 6, 031021
Phys. Rev. B, 94, 121112