What Wavelength Is a CO₂ Laser? Understanding 10,600 nm (10.6 µm)

CO₂ lasers are commonly associated with a wavelength of:

10,600 nm = 10.6 µm

This wavelength is in the infrared portion of the electromagnetic spectrum and is completely invisible to the human eye.

However, not every CO₂ laser operates at exactly 10,600 nm.

CO₂ lasers can operate on a number of different emission lines, including wavelengths around 9.3 µm, 9.6 µm, and 10.6 µm, depending on the design of the laser.

For laser safety purposes, always verify the actual operating wavelength of the specific laser system rather than assuming that every CO₂ laser operates at 10,600 nm.

Wavelength describes the distance between successive points of an electromagnetic wave.

It can be expressed in several units.

For CO₂ lasers:

10,600 nanometers (nm) = 10.6 micrometers (µm)

A micrometer is 1,000 nanometers, so the two values describe exactly the same wavelength.

You may therefore see the same CO₂ laser described as:

These all refer to the same wavelength.

No.

The human eye detects only a relatively small portion of the electromagnetic spectrum. A 10,600 nm CO₂ laser operates far outside the visible range.

This means there is no visible CO₂ laser beam for the eye to see.

Any visible light observed during CO₂ laser cutting, engraving, welding, or another process may come from the interaction of the laser with the material, an aiming beam, plasma, sparks, or other process emissions—not necessarily from the CO₂ laser beam itself.

An invisible beam can still present a serious laser hazard.

Never use the absence of visible light as an indication that a CO₂ laser is off or that an area is safe.

Wavelength is one of the most important parameters in laser safety because different wavelengths interact differently with:

A protective material that works extremely well at one wavelength may provide very different protection at another.

This is why laser safety equipment should always be evaluated for the specific wavelength or wavelength range produced by the laser.

The location of potential laser injury within the eye depends strongly on wavelength.

Visible and near-infrared laser radiation can pass through the front structures of the eye and be focused onto the retina.

At CO₂ laser wavelengths around 10.6 µm, the situation is different.

This long-wavelength infrared radiation is strongly absorbed by water. Because the cornea contains a large amount of water, CO₂ laser radiation is absorbed primarily near the front surface of the eye rather than being transmitted and focused onto the retina.

As a result, the cornea is a primary eye-hazard tissue for CO₂ laser radiation.

This does not make CO₂ lasers less dangerous. It means that the mechanism and location of potential eye injury are different from those associated with visible and near-infrared lasers.

For more information see here or the video below:

Materials do not interact with every wavelength in the same way.

A material can be:

This is particularly important with CO₂ lasers.

Materials that appear transparent or non-reflective to the human eye do not necessarily behave the same way at 10.6 µm.

For example, some polymer materials can provide substantial attenuation at CO₂ laser wavelengths even though they transmit visible light.

Conversely, a material that appears opaque or non-reflective to the eye should not automatically be assumed to safely absorb CO₂ laser radiation.

The material's performance must be evaluated at the actual laser wavelength.

Although 10,600 nm is the wavelength most commonly associated with CO₂ lasers, CO₂ molecules are capable of producing laser radiation on multiple emission lines.

Depending on the laser design, CO₂ systems may operate at wavelengths including approximately:

There are also additional CO₂ emission lines within the broader wavelength region.

Certain wavelengths can be intentionally selected because different materials absorb laser energy differently at different wavelengths. For example, a CO₂ laser operating near 9.3 µm may be advantageous for processing certain polymers.

For laser safety purposes, this creates an important rule:

Never select protective equipment based solely on the words "CO₂ laser."

Verify the actual wavelength.

Suppose a laser safety product provides protection from:

10,000–11,000 nm

A conventional 10,600 nm CO₂ laser falls within that wavelength range.

However, a CO₂ laser operating at 9,300 nm would fall outside that range.

The fact that both systems are CO₂ lasers does not mean that the same protective product automatically provides appropriate wavelength coverage for both.

This applies to:

Always compare the laser's actual operating wavelength with the tested or rated wavelength range of the protective product.

Wavelength tells you where protection is required spectrally, but it does not by itself tell you how much protection is required.

A complete laser hazard evaluation may also consider factors such as:

For the differences between the laser class and hazard evaluation see here and the video below:
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This is why knowing that a laser operates at 10,600 nm is essential—but it is not sufficient by itself to select laser safety equipment.

The wavelength most commonly associated with a CO₂ laser is:

10,600 nm = 10.6 µm

This radiation is invisible infrared radiation, and its wavelength strongly influences how the laser interacts with the eye, protective equipment, optical components, and other materials.

However, not all CO₂ lasers operate at exactly 10,600 nm. CO₂ laser systems can operate on other emission lines, including wavelengths around 9.3 µm and 9.6 µm.

For laser safety purposes:

Identify the actual wavelength → Match protective equipment to that wavelength → Evaluate the required level of protection

Never assume that equipment designed for 10,600 nm automatically provides protection for every CO₂ laser wavelength.