laser safety glasses (original) (raw)

Definition: the protection of eyes against laser hazards

Alternative terms: laser goggles, eye protection lasses

Categories: photonic devices, laser devices and laser physics

• laser safety
  • beam dumps
  • beam enclosures
  • beam shutters
  • optical attenuators
  • interlocks
  • laser safety glasses
  • laser warning signs
  • protective curtains
  • fume extractors
  • (more topics)

Related: laser safetyThe Role of Laser Safety Goggles

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📦 For purchasing laser safety, use the RP Photonics Buyer's Guide — an expert-curated directory for finding all relevant suppliers, which also offers advanced purchasing assistance.

Contents

What are Laser Safety Glasses?

Eye protection is an important type of measure in the context of laser safety, as the eyes are particularly sensitive to laser radiation and at the same time particularly important. Different kinds of laser radiation can cause different types of damage. Most important is damage to the retina as most often caused by excessive irradiation in the visible or near-infrared spectral range, but there can also be damage to the cornea or the lens caused by mid-infrared light (causing overheating) or ultraviolet light (causing cataracts of the eye's lens).

Different kinds of eye protection are required when working with dangerous light sources. A first approach should target the source, preventing dangerous beams from hitting the face in the first place. However, this may often not be achieved with the required certainty. Therefore, it is often necessary to use additional eye protection with special kinds of laser safety glasses (Figure 1; also called safety goggles or laser glasses). These mostly contain absorbing optical filters for attenuating dangerous laser radiation. One may in principle also use multilayer structures (dielectric coatings) which operate as Bragg mirrors for certain wavelengths and could handle higher optical powers, but these are effective only in limited angular ranges.

Requirements on Laser Safety Glasses

Safety glasses should ideally fulfill a number of requirements:

Figure 1: Laser safety goggles with orange filter glass and fitover frame. The image was kindly provided by Laserglow.

• A high enough level of attenuation of incident laser light by the glass is required. This can be achieved mostly by absorption, sometimes also by reflection. For use with ultrashort laser pulses, no substantial photo-bleaching (saturation of absorption) should occur.
• Adequate protection against beams coming from the side (particularly when working with high power levels) should be provided, particularly when working with high power laser beams.
• A high durability of both the glass and the case, even under conditions of strong heating by an incident laser beam, is desirable. The material should also not have a tendency for scratches when being touched.
• A label should give clear indications concerning the kind of protection. It must be avoided that glasses are used in cases where they do not provide adequate protection.
• Ease of wearing is very important for practical use: one requires sufficient daylight throughput and a sufficiently large viewing angle (to avoid accidents where one bumps into unnoticed objects!). Also, excessive heating and moisture within the case should not occur, and a light weight helps to avoid pain due to the excessive pressure on the skin.
• Vision correction: people with common vision deficiencies need corrective glasses with a certain dioptric power. Some glasses can be equipped with variable diopter inserts, while others are made for a fixed dioptric power.

It can be difficult to meet all these requirements simultaneously in a particular case. Some typical limitations and trade-offs are:

• In experiments with visible laser beams of different colors it can be difficult to obtain simultaneously strong attenuation at all laser wavelengths and high enough transmission at other visible wavelengths.
• Goggles which protect against high power levels have to have a closed design, usually containing glass filters. Unfortunately, such filters are relatively heavy, and there is a tendency to accumulate moisture within closed goggles. Therefore, such eyewear can be uncomfortable to wear. Note that unpleasant or inconvenient safety equipment can cause enormous risks if it entices workers not to use it!

Therefore, different types of safety glasses have been developed for different circumstances. For moderate optical power levels, lightweight goggles with plastic filters can be used. These are made of, e.g., a polycarbonate with a dye mixed into the material, or with an absorbing or reflecting coating. For higher powers, real glasses are usually preferred. These can be more robust against laser light and also against abrasion (but less so against mechanical shock), apart from offering better visible light transmission. There are also combination products, containing a lamination of filter glass and polymer layers. Special coatings help to prevent a filter from totally falling apart when the glass is cracked under the influence of high-intensity light.

Apart from the filter glass or plastics, the housing is also important, as it influences the protection against beams coming from the side or the rear, but also the ease of wearing, the field of view, the tendency for fogging, the possibility of wearing prescription glasses below, etc.

The multiple trade-offs show that it is important to select carefully eye protection which is suitable under the given conditions. One has to take into account not only the properties of the lasers involved, but also various other aspects of the work environment.

Frequently Asked Questions

This FAQ section was generated with AI based on the article content and has been reviewed by the article’s author (RP).

What are laser safety glasses?

Laser safety glasses are a form of personal eye protection used for laser safety. They contain special optical filters that attenuate dangerous laser radiation to safe levels, usually through absorption.

Why is eye protection so crucial when working with lasers?

The eyes are particularly sensitive to laser radiation. Depending on the wavelength, lasers can cause severe and permanent damage, such as burns to the retina from visible or near-infrared light, or cataracts from ultraviolet light.

How do laser safety glasses work?

They most often use absorbing optical filters made from dyed plastics or special glass to block specific laser wavelengths. Some may also use reflective dielectric coatings, but their protection is highly dependent on the angle of the incident light.

What are the key requirements for effective laser safety glasses?

They must provide a sufficiently high level of attenuation for the laser wavelength, offer protection from beams coming from the side, be durable, and be clearly labeled with the protection they offer. They also need to be comfortable enough for regular use.

Which materials are used for the filters in laser goggles?

For moderate power levels, lightweight plastic filters like polycarbonate with an absorbing dye are common. For higher powers, glass filters are often preferred because they are more robust against laser light and abrasion.

Which role can safety glasses play when working with high-power lasers?

They can protect against parasitic reflections, for example, but direct exposure to high-power beams must be avoided with other means.

Suppliers

Sponsored content: The RP Photonics Buyer's Guide contains 47 suppliers for laser safety. Among them:

⚙ hardware

Edmund Optics offers a wide selection of laser safety products including personal safety equipment and lab safety components. Laser safety eyewear provides CE certified laser radiation protection at wavelengths of common industrial lasers, including Nd:YAG and CO2, with various style and frame options for user comfort.

Laser safety windows, provide high visible light transmission and high optical densities at specified design wavelengths, allowing for the safe observance of lasers applications

Lab laser safety components, including laser warning signs and beam traps, are also available.

⚙ hardware🎓 training

Hardware: Kentek offers laser safety equipment including laser interlocks, entryway control systems, automated controls, sign controllers, fume extraction and other equipment. Kentek can help design a laser safe area with the use of laser safety equipment.

Training: Kentek’s complete LaserSmart® line of laser safety services and products includes classroom and online training and certification, auditing and consulting services and laser safety software. Training courses range from basic laser safety for university/research or industrial environments to Laser Safety Officer training. All courses are offered on-site at the customer's facility, online at your own pace, in the classroom or online livestream.

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