Abstract: A high power, cw, high pressure, electrically excited flowing gas laser is disclosed wherein a laser excitation transverse to the direction of gas flow is initiated by an electron beam perpendicular to the gas flow direction. The electron beam has a cross-sectional area conforming substantially to that of the excitation region and is especially profiled to have a cross-sectional electron density which varies as a function of distance along the direction of gas flow from substantially a minimum value at the upstream and downstream extremities of the excitation region to a maximum value approximately midway along the excitation region. This profiling, which may be achieved by tapered width apertures in either an electron beam window support member or in an electron gun grid, provides an appropriate heat input to the laser gas to minimize gas density variations in the excitation region and thereby optimize the beam quality of the generated laser beam.

Abstract: A waveguide gas laser is disclosed wherein narrow resonances in the loss vs. wavelength characteristics of a hollow waveguide laser resonator are employed to achieve wavelength selectivity. The laser includes a capillary bore waveguide of radius a and length 2L (or length L in a half-symmetric arrangement) which contains a laser gas having a laser transition capable of providing stimulated emission of light at wavelength .lambda.. The aforementioned loss resonances are achieved when the waveguide dimensions and the wavelength .lambda. are of preselected values satisfying the relation ##EQU1## where N is a positive integer.

Abstract: A periodic permanent magnet electron beam focusing arrangement integrated with a traveling-wave tube coupled cavity slow-wave structure is disclosed which achieves maximum peak power output in a compact design of minimum size, weight and cost. A plurality of annular permanent magnets and ferromagnetic pole pieces are alternately disposed coaxially about the electron beam path, with the pole pieces extending slightly radially inwardly of the magnets. A number n (where n is a positive integer not less than two) of annular platelike members and (n - 1) annular spacer members, each of electrically conductive non-magnetic material, are disposed radially within each magnet. The inner circumferential surfaces of the spacer members and of the pole pieces constitute lateral walls for different ones of the slow-wave structure interaction cavities, the broad surfaces of the plate-like members constituting end walls for the cavities.