1083 nm ytterbium doped fibre amplifier for optical pumping of helium

A combination of a narrow linewidth, tunable DBR diode laser and high power ytterbium fibre amplifier in a master oscillator power fibre amplifier (MOPFA) configuration is demonstrated for efficient optical pumping of helium. A compact and efficient diode pumped prototype system is shown to compare favourably with alternative laser sources for production of hyperpolarised /sup 3/He using direct pumping for medical application in MRI.