9B62.00 Visible Laser
PURPOSE: To demonstrate the operating properties of a laser cavity. Also, to see the inside of a laser, and observe the spectrum of the light inside and outside the laser tube, and to see the normal modes of the laser beam.
DESCRIPTION: This demo uses two accurately aligned concave mirrors. The mirrors are aligned externally to a cell of HeNe gas excited with high voltage. By carefully mis-adjusting the mirrors, the modes of the cavity can be sen in the laser spot.
Using hand-held diffraction gratings, the spectrum of the light inside and outside the
laser tube can be seen, allowing observation of the optical effect of the lasing action.
The light inside the tube
can be seen through a series of slits along the tube's length. The single wavelength of
light in the external beam
can be seen as the red dot on the top of the spectra above.
http://www.physics.umd.edu/deptinfo/facilities/lecdem/p3-71.htm
EQUIPMENT: Laser cavity
JZ 6/15/00