GB774475A - Improvements in or relating to apparatus for generating optical radiation of high power - Google Patents

Abstract

774,475. High-frequency supply systems for space discharge apparatus. TOUVET, G. Jan. 12, 1951, No. 6512/53. Divided out of 774,471. Drawings to Specification. Class 38 (4). [Also in Group XL (a)] Apparatus for producing optical radiation (infra-red to ultra-violet) comprises a gas (particularly xenon) or vapour-filled coiled or folded discharge tube excited by electric current of radio-frequency (or by radio-frequency components of current pulses) between two identically similar electrodes, the frequency, waveform and strength of the exciting current, the composition and pressure of the gas or vapour filling and the shape and dimensions of the tube being so chosen in combination that one or more lines in the spectrum of the filling are split into a multiplicity of lines by the magnetic field set up by the current flowing through the tube and that the intensity of the resulting radiation is enhanced in one or more regions of the spectrum by increasing the amplitude of particular spectral components or by broadening a line spectrum into a band. A coiled tube has a higher self-inductance than a folded tube and is suitable for use at lower radio-frequencies. The radio-frequency of the exciting current may be above 50 Mc/sec. and can be between 60 and 100 Mc/sec. In a particular example described a xenon-filled discharge tube consisting of two coaxial coils is excited by current at 100 kc/sec. Currents of about 1 ampere and 100 amperes per sq. cm. are referred to. Small changes in the frequency of the exciting current cause small shifts along the spectrum of the enhanced bands of the radiation and large changes cause the enhancing of the spectral lines to occur at a different part of the spectrum. The tube can have a sinusoidal input or can be operated in Class B or Class C or by very short D.C. impulses, of the order of 1 microsecond, containing radio-frequency transients. Circuits for exciting the tube are described in Specifications 774,471, 774,474 and 774,477. The tube may form part of the inductance of a tank circuit or may generate oscillations through possessing negative resistance as referred to in Specification 774,471. Applications to television, lowaltitude altimetry, range-finding, radar and remote control are referred to. Specification 386,492 also is referred to.