Laser Power and Laser Wavelength

Majority people are curious about how power a laser pointer can be, and relation between laser output power and wavelength. Which color laser pointer is the most powerful one with same range of output power? Even though with the same output power, different wavelength laser pointer would emit different power and energy. The laser pointer power is related to factors below:

Laser Beam Divergence

The bigger the laser beam divergence angle, the close its targeted range. Low beam divergence laser pointer has superior advantages than big divergence laser devices. Under condition of the same light emitting area, longer wavelength laser pointer has bigger laser beam divergence. As a result, red laser has longer beam visibility than infrared laser.
However, different kinds of laser pointers generate different mechanism. It is difficult to achieve the same light emitting area with the output power pointing. For instance, the light emitting area of 808nm infrared laser is larger than 980nm IR lasers. 808nm infrared laser has larger laser beam divergence than 980nm infrared laser pointer under circumstance of same output power.

Laser Focusing Limit

Close distance focusing laser radiation damage is corresponding long range. When the parallelism of the laser is the same, different wavelength laser has different focusing limit. For instance, focusing limit of 1064nm infrared laser is about 20 times of 532nm green laser. In other words, the 532nm green laser radiation strength on unit area is 20 times stronger than 1064nm infrared laser with same output power. Generally speaking, longer wavelength laser devices has bigger focusing limit than low powered lasers.

Thermal Effects and Penetration

The intense laser beam has caused hurt to human eyes or skins. Low penetration laser pointer has better performance in laser energy density. However, there is no absolute correlation between laser wavelength and penetrating. Among all visible lasers, longer wavelength laser pointers have better penetration than short wavelength lasers. But in long wavelength infrared lasers, with obvious thermal effect, whose penetrating strength becomes very weak. CO2 lasers are able to engrave glass, but 532nm green lasers cannot.

Absorption

Different color objects have a very significant difference in the ability to absorb various wavelengths of laser light. The same color has the weakest absorption result, which is relevant to white color. However, anti-color objects have the most obvious absorbing result. For example, green laser pointer can easily light up matches, but it is more strenuous to light up green head matches.

Lonization

This part mainly mentions to ultraviolet light. Since ultraviolet laser has high photon energy, so that it can make the target ionization. For organic life, the ionization effect of UV lasers will destroy a various protein and enzyme activity, which is the principle of UV light disinfection. As a result, UV laser is undoubtedly the strongest laser among various wavelengths in body destruction of life.

Sensitivity of Human Eyes

Human eyes have the most sensitive feeling to yellow-blue lasers around the wavelength of 550nm. Among all visible laser wavelength range, human eyes can be more easily hurt by laser wavelength near this range.