Frequency-narrowed tunable external-cavity 2.5-W diode laser for spin-exchange optical pumping

Summary form only given. Liter quantities of spin-polarized /sup 129/Xe are of utility for a number of applications, including MRI. The hyperpolarized /sup 129/Xe is produced via spin-exchange collisions with laser-polarized Rb atoms. Commercially available diode arrays, while compact and inexpensive, have bandwidths of typically 2-3 nm, far in excess of the 0.1-0.3 nm pressure-broadened Rb absorption linewidth. Recently, Levron et al. (see Appl. Phys. Lett. vol. 73, p. 2666, 1998), frequency narrowed a custom 1-W diode to use for spin-exchange optical pumping of Xe using Cs instead of Rb. The resulting 0.3-W output with 0.12-nm bandwidth gave Xe polarizations of 2.5%. Here we achieve nearly a factor of 10 increase in power at the same linewidth using commercial broad area diode lasers (BALs) with external-cavity feedback.