Laser Classification | Medical Health Physics (2024)

FAQs

How do you determine laser classification? ›

Classification is determined by calculations based on exposure time, laser wavelength and average power for CW or repetitively-pulsed lasers and total energy per pulse for pulsed lasers.

Laser Classes chart

There are four main classes for visible-beam lasers: Class 2, Class 3R, Class 3B and Class 4. The first two are relatively safe for eye exposure; the last two are hazardous. The chart below shows that the eye injury hazard increases as the laser's power increases.

A Class IIIa laser is considered safe if handled carefully, with restricted beam viewing. With a class IIIa laser, the maximum permissible exposure (MPE) can be exceeded, but with a low risk of injury. Visible continuous lasers in Class IIIa are limited to 5 mW.

Most of the lasers dermatologists use are Class 4, which can produce the most serious hazards.

Most surgical and medical lasers are Class III or IV. Some lasers have a Class IV therapy level beam plus a Class I or II alignment beam.

Class 3-Medium Power Lasers and Laser Systems (top)

This laser will not pose either a fire hazard or diffuse-reflection hazard. They may present a hazard if viewed using collecting optics. Visible CW HeNe lasers above 1 mW, but not exceeding 5 mW radiant power, are examples of this class.

Class 5 Photonics offers ultrafast, high power laser systems and EUV sources for demanding applications from bio-imaging to ultrafast science and attosecond science.

Currently, the most powerful laser at CLF is the Vulcan laser, which has a wide range of uses, predominantly in plasma physics. The upgraded Vulcan 20-20 laser will be 100 times brighter than its predecessor, and a million, billion, billion times brighter than the Sahara Desert's brightest sunlight.

Laser safety glasses actively disrupt specific wavelengths of light, effectively blocking those targeted wavelengths while allowing the passage of other light through specially crafted lenses. This capability enables uninterrupted work without the hindrance of darkness or hazardous laser beams.

Class 1. A Class 1 laser is safe under all conditions of normal use. This means the maximum permissible exposure (MPE) cannot be exceeded when viewing a laser with the naked eye or with the aid of typical magnifying optics (e.g. telescope or microscope).

Are class 2 lasers safe? ›

Class 2 lasers are considered safe for normal operation.

(In the U.S., pointers can also be Class 3R.) Class 2 is the same as the Roman numeral "Class II" you may see on some lasers' labels.

This class is eye-safe under all operating conditions. A Class 1 laser is safe for use under all reasonably anticipated conditions of use; in other words, it is not expected that the MPE can be exceeded.

Class 3R lasers are considered safe when handled carefully.

There is only a small hazard potential for accidental exposure.

Class IV: High power lasers (cw: 500 mW, pulsed: 10 J/cm² or the diffuse reflection limit) are hazardous to view under any condition (directly or diffusely scattered) and are a potential fire hazard and a skin hazard. Significant controls are required of Class IV laser facilities.

Lasers that fall under the class 4 category are among the most dangerous. They can burn your skin and cause severe, permanent damages to your eyes.

A laser generates a beam of very intense light. The major difference between laser light and light generated by white light sources (such as a light bulb) is that laser light is monochromatic, directional and coherent. Monochromatic means that all of the light produced by the laser is of a single wavelength.

One thing remains certain, current scientific and clinical research proves that class 3B lasers are best suited for therapeutic applications and class 4 lasers are best suited for tissue destruction. Bibliography: 1) In vivo effects of low level laser therapy on inducible nitric oxide synthase.

Laser classification is marked on the equipment. Laser classes are: Class 1: A class 1 laser is safe under all conditions of normal use and poses no more risk than ordinary light. CD-ROM readers and laser printers are class 1 lasers.

Class 3 lasers have between 1 and 500 mW. This group is referred to as therapeutic 'cold' lasers and come with 'eye caution to eye danger'. Class 4 lasers have more than 500 mW and are referred to as 'hot' lasers.