A plasma source utilizing direct current (DC) voltage between an anode and a hot hollow cathode is employed to create high-density plasma. Plasma spatial distribution, ion energy, plasma neutralisation, and current densities are found to be separately tunable. Ion current densities >0.5 mA/cm2 have been demonstrated over coating areas >1 m diameter. The primary advantage of plasma, as opposed to the ion source approach, is its ability to fill in the vacuum chamber and the couple with evaporant. This induces partial evaporant ionisation, providing uniform ion-assisted deposition over extended coating areas. Optical thin film properties deposited using the adapted high ion current plasma source are likewise described.