A combination of a narrow linewidth, tunable DBR diode laser and high
power ytterbium fibre amplifier in a master oscillator power fibre amp
lifier (MOPFA) configuration is demonstrated for efficient optical pum
ping of helium. A compact and efficient diode pumped prototype system
is shown to compare favourably with alternative laser sources for prod
uction of hyperpolarised He-3 using direct pumping for medical applica
tion in MRI.