QUANTUM-NOISE PROPERTIES OF SMALL GAS-LASERS

If a laser is made sufficiently small, its (unavoidable) technical noi se can be overwhelmed by the quantum noise, i.e. the spontaneous emiss ion. We discuss the conditions which are required for this situation t o occur, specializing to the case of a small gas laser. Experimental e xamples taken from recent work are used to illustrate the quantum regi me of phase noise and polarization noise. Using scaling arguments we c ompare these quantum-noise effects in small gas lasers with those in s emiconductor lasers.