Abstract: A light source including a gaseous medium which is excited to a light-emitting state by means of a microwave electromagnetic field, wherein the electromagnetic field is generated by circularly polarised microwave radiation. A preferred form of the invention is a laser.

Abstract: An apparatus for producing chemically active species by passing a precursor gaseous medium through a plasma at pressures of at least 50 millibars is described.

Abstract: A method of removing particulate and other materials from the exhaust gases from an internal combustion engine in which the exhaust gas is passed through a bed of charged ferro-electric materials. Three forms of apparatus for carrying out the method are described.

Abstract: A microwave plasma generator including a chamber within which there is a pair of opposed field-enhancing electrodes one of which has an axial hole through which gas which has been activated into a plasma state in the region between the electrodes can be extracted from the chamber.

Abstract: A method of and apparatus for removing organic material from a gas. The method comprises the operation of subjecting the gas to pulses of circularly polarised microwave radiation and the apparatus comprises a reaction chamber through which the gas can be passed, means for generating circularly polarised microwave radiation and means for applying the circularly polarised microwave radiation to the gas in the reaction chamber.

Abstract: A filamentless (without a heated cathode) ion source for thin film processing and surface modification. The ion source comprises a plasma chamber which includes a wall defining an evacuable chamber having a first end and a second end, with a dielectric member extending across the first end of the evacuable chamber. A gas inlet admits a plasma forming gas into the chamber. An RF emitter is positioned adjacent to the dielectric member for inductively generating a plasma in the gas in the plasma chamber during use of the ion source. A control grid structure is provided for extracting ions from plasma in the plasma chamber, and include a first grid connected to a positive voltage source and a second grid connected to a negative voltage source, to produce an acceleration field for accelerating ions towards and through the second grid of the control grid structure. An ion beam processing apparatus and an ion beam neutralizer incorporating such an ion source are also described.