Improvements In Copper Vapour Laser Technology: New Applications

Abstract

Recent advances are described which have resulted in improvements to the performance of copper vapour lasers (CVL), operating at 511nm and 578nm, with specific reference to ultra fast pulse amplification and high speed photography. Collaborative work between Oxford Lasers Ltd. and the University of Aachen has resulted in the development of a copper vapour pump laser with 10ns pulse width, peak power of order 150kW, repetition rate of up to 20kHz and an output beam divergence close to the diffraction limit. With optical fibre beam delivery systems, high levels of laser illumination can be achieved in locations inaccessable to conventional strobe sources. In textile manufacture for example, the spinning process in which individual fibres are incorporated into yarn has been studied. The 3Ons pulse length of the Oxford Lasers CU10 ensures that high resolution images of individual fine (10 micron) fibres are recorded. Advances in the design of the pulsed electronic circuitry have enabled not only extremely high repetition rate operation of the CVL to be achieved, but allows the frequency to be continuously varied over wide ranges. This ensures that maintaining synchronization with rotating prism cameras, even during the run-up phase of the camera, presents no problem. Improvements to the design of the laser head itself have led to operation at significantly higher overall efficiences (>1%) resulting in the upgrading of existing specifications. Advances in the cavity design have allowed these high powers to be realised as focusable laser light. The examples we present show how versatile the CVL technology has become in a rapidly expanding range of applications and illustrate the potential for the CVL to achieve the status as the 'work-horse' pulsed high power laser.