John,
There was an article in AJP a few yearsago that "stablized" a He/Ne
laser, by heating the tube in a servo loop that monitored the polarized
light level. This kept the cavity at one frequency and reduces the frequency
noise by allowing only one mode to oscillate.
Gary
Gary Karshner
St. Mary's University
San Antonio, Texas
KARSHNER@STMARYTX.EDU