Advantages of Semiconductor Laser Diodes Versus Helium Neon Gas Lasers

Although HeNe gas lasers offer exceptional reliability and optical quality, users are quickly replacing them in their OEM applications with semiconductor laser diode technology. Laser diode modules offer many physical and electronic advantages over HeNe lasers. HeNe gas lasers provide superior optical characteristics. While laser diodes must take advantage of external optics to yield a high quality output beam, HeNe output is well-collimated and does not require external optics. HeNe lasers also offer excellent coherence lengths (10cm to several meters), and most small tubes operate as single mode (TEM00). Laser diode modules are smaller, more efficient, and more versatile than HeNe lasers. For example, one of our more popular laser diode modules, the PPM, measures approximately 1.5 inches in diameter and 5.7 inches in length, while our smaller RC unit measures only 0.5 inch in diameter and 1.3 inches in length. Also, laser diode modules typically require less than 0.5W of energy, whereas an average HeNe laser requires 10 to 20W of energy to produce a few milliWatts of light. In addition, laser diodes provide an abundance of available wavelengths in the ultraviolet, visible, and infrared, while HeNe lasers limit users to half a dozen or so wavelengths.