Demonstration of the spectrum of laser light from a He-Ne laser with external mirrors showing multiple frequencies associated with longitudinal modes of the cavity

Demonstration of the polarization of the multiple frequencies being identical

Demonstration of the effect of temperature, vibration, and misalignment of the spectrum of the laser output

Demonstration of the spectrum of laser light from a He-Ne laser with internal mirrors, showing multiple frequencies associated with longitudinal modes of the cavity

Demonstration of the polarization of the multiple frequencies from an internal mirror laser showing that adjacent modes are orthogonally polarized

Demonstration of single-frequency output by polarization selection

Demonstration of the effect of temperature on the spectrum of the laser output