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Laser Basics


ºC  Degrees Celsius
A   Amperes
mA   Milliamp
Hz  Hertz
AC  Alternating Current
cm  Centimeter
mm  Millimeter
nm  Nanometer
μm  Micrometers
CW  Continuous Wave
PW  Pulsed Wave
SP  Super Pulsed
W  Watts
mW  milliWatts
mS  Millisecond
μs  Microsecond

LASER:  acronym that stands for Light Amplification by the Stimulated Emission of Radiation. Lasers emit light that is monochromatic (a single color or wavelength), coherent (in phase), and collimated.

Fluence:  a measure of instantaneous power output from the laser typically measured in Watts

Wavelength:  length between two identical points on subsequent electromagnetic waves. The wavelength of a laser determines it’s color and absorption properties.

Irradiance:  power per unit area at a treatment surface

Dosing:  most common dosing technique in laser therapy is the energy density delivered to the surface of the tissue which is typically expressed in J/cm2.
Note: Companion Therapy provides a treatment guide with each device with recommended doses for clinical conditions. The calculators below can be used as a guide to assist in conversions.

Laser Classifications:  laser safety classifications in the US by the American National Standard Identification (ANSI) and globally by the International Electrotechnical Commission (IEC). The classifications below from the revised system (2002) apply to non-magnified laser devices.

Class 1:  safe under all conditions of normal use.

Class 2:  applies to only visible light lasers (400-700nm). These devices are considered eye-safe because the blink reflex will limit exposure to less than 0.25 seconds. Intentional suppression of the blink reflex could lead to eye injury. Most laser pointers are class 2 devices.

Class 3R:  3R lasers in the visible spectrum have continuous wave (cw) emission of 5mw or less. These devices are considered safe if handled carefully with restricted beam viewing

Class 3B:  3B lasers are hazardous to the eye when viewed directly. For visible and infrared devices emission power is limited to 0.5W. Protective eyewear, key switch and safety interlock are required safety features.

Class 4:  Class 4 lasers include all lasers that emit power in excess of 3B limitations. Eye protection is needed to limit both direct and diffuse reflected exposure. Key switch and safety interlocks are also required safety features. Most scientific, industrial, military and medical lasers fall into this category.