All-optical production of lithium-6 molecular Bose-Einstein condensates in excited hyperfine levels

We demonstrate the achievement of molecular BECs of lithium-6 in its lowest and second lowest hyperfine state pairs at 0.05 microkelvin by an all-optical method. At such temperature, the mixture of the lowest two states has a condensate fraction of 36{\%} with 9E$+$4 atoms while mixture of the second lowest two states has a condensate fraction of 28{\%} with 3.2E$+$4 atoms. Our method, although being mostly standard, introduces several unique features. For example, we add a few refinements to the Bitter-type magnetic bias coils. Utilizing a high-vacuum chamber, our design preserves a lot of optical access for future experiments and minimizes the use of active elements. By using a single tapered amplifier, we realize slowing and Doppler-cooling. We also implement a phase contrast imaging system to investigate the imbalances between hyperfine states in lithium.