A simple laser teaching aid for transverse mode structure demonstration

摘要

A teaching aid for demonstrating the transverse mode structure in lasers is described. A novel device called ‘multi-dimension adjustable combined cat-eye reflector' has been constructed from easily available materials to form a He-Ne laser resonator. By finely adjusting the cat-eye, the boundary conditions of the laser cavity can be altered, which allows the transverse modes output by laser to be conveniently modulated. Equipped with a CCD imaging system, this apparatus allows more than 20 laser transverse modes to be visualized on the computer screen, provided a valuable teaching aid at an undergraduate level.