Faculty Sponsor: John Yukich
This experiment examines the longitudinal and transversal modes of operation of a helium-neon (HeNe) laser, and produces a highly mono-chromatic beam from a multi-mode laser using an etalon. We investigate the relationship between longitudinal mode spacing and the distance between two reflective mirrors on each side of the laser tube. We also compare the distribution of longitudinal mode frequencies to that of the oscillation frequencies for a standing wave with fixed ends. In addition, we observe the effect of an etalon on the number of modes for the laser output. Lastly, we examine different transverse modes by introducing a crosshair lens that splits laser signal.