1. HELIUM NEON LASER
Koen van Aken

2. Introduction One of the first gas-lasers; developed in1961
Operating lifetime exceeds 50,000 hours
He:Ne in range 5:1 to 10:1
Electrical discharge initializes process.
Operating wavelength nm at mW
Other transitions at 3.39 micrometer, 543 nm, 594 nm and 612 nm

3. Relevant transitions

4. Characteristics Typical cavity length in range 0.15m-1m
Half symmetric confocal cavity
Doppler broadened, FWHM = 1.5 GHz
Multiple longitudinal modes; not purely monochromatic
TEM00

5. Low energy Ne-He laser therapy
Wu, C.S., Hu, S.C.S, Lan, C.C.E., Chen, G.S. Chuo, W.H. and Yu, H.S.
Journal of Medical Sciences, v24, i4, April 2008, pp
Effects of He-Ne laser light on skin disease Segmental Vitiligo.
Repigmentation was observed for 60% of patients
Blood flow significantly higher and repair of nerve dysfunction