A Compact And Efficient He-CdII White Light Laser

An efficient and simplified electrode design for the concentric cylindrical type hollow cathode structure of which the discharge length is as short as 19cm can perform the white light laser operation which employs three primary colors from 636.Onm (red), 537.8nm (green) and 441.6nm (blue) lines of CdII transitions. As a measure to quantify the trade-off between hollow cathode effect and Cd vapor diffusion, we consider the loss of cathode area defined by the ratio of total lost areas due to cathode holes to whole inner areas of the cathode cylinder. The cathode dimensions should be properly designed to have the optimum loss of cathode area of 8.0%. By this design, the white light laser operation was achieved with discharge length as short as 19cm, and the total white light output at maximum power was estimated to be more than 1mW.