Laser safety window markings provide important information about the protection offered by the window.

These markings and specifications help identify:

Because laser protection is wavelength-specific, understanding these markings is an important part of verifying that the correct laser safety window is being used for a particular laser system and application.

The most important information on a laser safety window is typically the wavelength range and corresponding Optical Density (OD).

For example, a laser safety window may be marked:

The wavelength range identifies the portion of the spectrum where the protection applies, while the Optical Density identifies the minimum level of attenuation provided within that range.

For example:

OD 7+ @ 1060–2500 nm

means the window provides an Optical Density of at least 7 throughout the specified wavelength range from 1060 nm through 2500 nm.

Laser safety protection is wavelength-specific. A window may provide a high Optical Density at one wavelength while providing substantially less protection at another wavelength.

For additional information on Optical Density and wavelength notation, see our Optical Density (OD) guide.

Laser safety window markings identify the wavelength range and Optical Density (OD) provided by the filter. Understanding these specifications is important when verifying that a window provides appropriate protection for a particular laser wavelength and application.

The video below explains how Optical Density and wavelength markings are read and what these specifications mean for laser safety filters.

Although the example shown uses laser safety eyewear, the same fundamental Optical Density and wavelength notation is also used to describe the protection provided by laser safety windows.

When reviewing a laser safety window, always verify both the wavelength range and Optical Density against the requirements of the laser system and application.

When reading a laser safety window marking, look for two primary pieces of information:

1. Wavelength or Wavelength Range

This identifies the laser wavelengths where the specified protection applies.

For example:

1060–2500 nm

indicates that the specification applies throughout that wavelength range.

2. Optical Density

Optical Density describes how strongly the window attenuates laser radiation within the specified wavelength range.

For example:

OD 7+

indicates an Optical Density of at least 7 throughout the associated wavelength range.

Together:

OD 7+ @ 1060–2500 nm

indicates that the window provides at least OD 7 protection from 1060 through 2500 nm.

When evaluating a laser safety window, both the wavelength range and Optical Density must be considered together.

The color or appearance of a laser safety window does not tell you what wavelengths it protects against.

Two windows that appear similar may have very different Optical Density specifications and wavelength coverage.

Clear markings and product identification allow users to verify that:

The protective specifications should always be verified rather than assuming protection based on the appearance or color of the window.

Laser safety windows and laser safety eyewear both commonly use Optical Density and wavelength ranges to describe laser attenuation.

However, this does not mean that a laser safety window necessarily requires the same Optical Density as the eyewear used with the laser.

Eyewear and windows may be exposed to very different levels of laser radiation depending on their location, the beam path, distance, reflections, and the design of the laser controlled area.

For additional information, see: Does a Laser Safety Window Need the Same Optical Density as Laser Safety Glasses?

OD stands for Optical Density.

Optical Density describes the amount of attenuation provided by the window at a specified wavelength or wavelength range. Higher OD values represent greater attenuation.

The wavelength range identifies the portion of the laser spectrum where the stated Optical Density applies.

For example:

OD 7+ @ 1060–2500 nm

means that the window provides at least OD 7 protection throughout the 1060–2500 nm range.

No.

The appearance or color of a laser safety window should not be used to determine its protective characteristics.

Always verify the wavelength and Optical Density specifications associated with the window.

No.

A higher Optical Density provides greater attenuation, but laser safety window selection is not simply a matter of choosing the highest available OD.

The window must provide appropriate protection at the specific laser wavelength while also providing suitable visibility for the application.

Not necessarily.

The required protection depends on the potential laser exposure at the location of the window. A laser safety window and laser safety eyewear may therefore have different OD requirements even when used with the same laser system.

If the protective specifications cannot be reliably identified, the window should not be assumed to provide the required laser protection.

Product documentation, manufacturer information, or other reliable records should be used to verify the window's wavelength range and Optical Density before relying on it as part of the laser safety system.