What Laser Safety Window Do I Need for a 1060–1080 nm Fiber Laser?

Fiber lasers operating in the 1060–1080 nm range are commonly used for applications such as laser welding, cleaning, cutting, marking, and engraving.

When selecting a laser safety viewing window for one of these systems, two fundamental questions need to be answered:

A laser's wattage alone does not answer either question.

First, verify the operating wavelength specified by the laser manufacturer.

Common wavelengths in this range include:

Do not assume that a window providing protection at one wavelength automatically provides the same protection at another.

For example, a window rated through 1070 nm should not automatically be assumed to provide protection at 1080 nm.

The actual laser wavelength must fall within the window's specified wavelength protection range.

Matching the wavelength is only the first step.

The window must also provide sufficient optical density (OD) at that wavelength.

Optical density describes how strongly the window attenuates laser radiation. The required OD should be determined as part of the laser hazard evaluation based on the reasonably foreseeable worst-case exposure conditions at the window.

If your hazard evaluation has already established a requirement such as:

OD 6+ @ 1064 nm

you can compare that requirement directly against the laser safety window manufacturer's published OD specifications.

The selected window should provide at least the required OD at the applicable wavelength.

As part of the hazard evaluation, you may also find the LIA Optical Density Calculator helpful for evaluating OD requirements. For how to read optical density notation see here:

A common question is:

“I have a 200 W 1064 nm fiber laser. What OD window do I need?”

Knowing that the laser is 200 W is useful information, but laser power alone does not determine the required OD at the viewing window.

The potential exposure at the window can depend on factors such as:

This is why two systems with lasers of the same wavelength and power may not necessarily present identical exposure conditions at their viewing windows.

Window location is an important part of the hazard evaluation.

A viewing window located outside the expected primary beam path and primarily exposed to scattered or diffuse laser radiation may experience a very different potential exposure than a window positioned where a direct or specular beam could strike it.

However, you should not simply assume that a viewing window will only encounter diffuse radiation.

The evaluation should consider the actual system geometry and reasonably foreseeable worst-case beam paths and reflections that could expose the window.

This is also why the OD required for a laser safety viewing window does not necessarily have to be identical to the OD required for laser safety eyewear.

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

Many high-power fiber laser sources are Class 4, but the laser classification does not by itself tell you what OD your viewing window requires.

Laser classification and laser hazard evaluation serve different purposes.

A laser classification describes the laser product according to its accessible emission and potential hazard under specified conditions.

A laser hazard evaluation considers the actual application, potential exposure conditions, and tasks being performed to determine appropriate safety controls.

For more information, see:

Laser Classification vs. Hazard Evaluation: What's the Difference?

Watch: Laser Classification vs. Hazard Evaluation

Many fiber laser systems incorporate a visible aiming, guide, or alignment beam in addition to the primary operating laser.

For example, you may see a visible red beam while the primary operating laser is an invisible near-infrared wavelength around 1064 or 1070 nm.

These are different wavelengths and should not be confused when selecting laser safety protection.

Any accessible laser emissions that could present a hazard should be considered as part of the laser hazard evaluation.

For more information, see Operating Beam vs. Aiming Beam: What's the Difference?

Laser radiation in the 1060–1080 nm range is near-infrared and invisible to the human eye.

Radiation in this wavelength range can pass through the front structures of the eye and reach the retina, where the eye can focus the radiation onto a small area of retinal tissue.

Because the beam is invisible, you also cannot rely on visible brightness to recognize the presence or intensity of the laser radiation.

Appropriate engineering controls, viewing windows, PPE, and other safety measures should therefore be determined from the actual laser hazard evaluation.

The 1060–1080 nm wavelength range includes both continuous-wave (CW) and pulsed laser systems.

For pulsed lasers, parameters such as:

may be relevant to the hazard evaluation.

Do not assume that a window selected for one 1064 nm laser application is automatically appropriate for another system simply because both lasers operate at the same wavelength.

For a 1060–1080 nm fiber laser, start by verifying the actual operating wavelength.

Then determine the required protection based on the reasonably foreseeable worst-case exposure conditions at the viewing window.

If you already know that you require a specific OD across a specific wavelength range, compare that requirement directly against the window manufacturer's published OD specifications.

Do not select a laser safety viewing window based solely on the laser's wattage, Class 4 designation, or the fact that it is a fiber laser.