Laser light is commonly classified according to its wavelength,
which is measured in nanometers (nm).
Different wavelengths produce different colors, visibility levels and optical characteristics.
They also determine which laser module is suitable for a particular application.
Blue, violet and green lasers are part of the visible spectrum,
while infrared lasers are generally invisible to the human eye.
Understanding these wavelength ranges can help engineers and buyers
select the correct laser source for positioning, detection, machine vision, measurement and other industrial applications.
The following table shows the commonly accepted wavelength ranges for violet, blue, green, red and infrared lasers.
| Laser Type | Wavelength Range | Common Laser Wavelengths | Visibility |
|---|---|---|---|
| Violet laser | 380–450 nm | 395 nm, 405 nm, 410 nm | Visible, but relatively dim |
| Blue laser | 450–495 nm | 445 nm, 450 nm, 455 nm, 460 nm, 473 nm | Visible |
| Green laser | 495–570 nm | 505 nm, 510 nm, 515 nm, 520 nm, 525 nm, 532 nm | Highly visible |
| Red laser | 620–750 nm | 635 nm, 650 nm, 660 nm | Visible |
| Infrared laser | Above approximately 750 nm | 780 nm, 808 nm, 850 nm, 905 nm, 940 nm, 980 nm, 1064 nm | Normally invisible |
The exact boundaries may vary slightly between scientific references and manufacturers.
For laser module selection,
the specified center wavelength and wavelength tolerance are more important than the general color category.
Violet lasers normally operate between approximately 380 nm and 450 nm.
The most common wavelength used in compact violet laser modules is 405 nm.
Although 405 nm light is visible, the human eye is much less
sensitive to violet light than to green light. Therefore,
a 405 nm laser may appear less bright than a green laser with the same optical output power.
Common applications of violet laser modules include:
Violet laser light is sometimes called purple laser light in commercial descriptions.
However, from a scientific perspective, violet is a spectral color,
while purple is generally perceived as a mixture of red and blue light.
Blue laser wavelengths generally range from approximately 450 nm to 495 nm.
Compact industrial laser modules commonly use 445 nm,
450 nm, 455 nm or 460 nm laser diodes.
The 450 nm blue laser is especially popular because
it offers a strong visual effect and is available in multiple optical power levels.
Depending on the optical design, blue laser modules
can generate a dot, line, cross, circle, grid or custom beam pattern.
Typical applications include:
Blue lasers normally offer good visual contrast on red,
orange and certain dark-colored surfaces.
However, ambient lighting and the color and reflectivity of the target surface can significantly affect visibility.
Green lasers cover approximately 495 nm to 570 nm.
Common industrial wavelengths include 505 nm, 515 nm, 520 nm, 525 nm and 532 nm.
The human eye is highly sensitive to green light.
As a result, a green laser can appear significantly brighter than a red,
blue or violet laser with similar output power. This makes green laser modules suitable for applications requiring high visibility.
Two widely used green wavelengths are:
A 520 nm laser is normally generated directly by a semiconductor laser diode.
It offers a compact structure, stable performance and convenient modulation.
It is widely used in positioning and industrial laser modules.
A 532 nm laser is commonly produced by a diode-pumped solid-state system.
It provides a bright and highly visible green beam but may require more complex
temperature and power control than a direct-diode 520 nm laser.
Common applications of green laser modules include:
When the laser must remain visible in a bright environment,
a green laser is often preferred. However, the final selection should also consider laser power,
beam diameter, operating distance and ambient light.
Infrared lasers operate beyond the visible red spectrum,
generally at wavelengths above approximately 750 nm.
Most infrared laser modules are invisible or nearly invisible to the human eye.
Common wavelengths include 780 nm, 808 nm, 850 nm, 905 nm, 940 nm, 980 nm and 1064 nm.
Infrared light can be divided into several spectral bands:
| Infrared Band | Approximate Range | Typical Applications |
|---|---|---|
| Near-infrared (NIR) | 750–1400 nm | Night vision, sensing,positioning and distance measurement |
| Short-wave infrared (SWIR) | 1400–3000 nm | Material identification,imaging and spectroscopy |
| Mid-wave infrared (MWIR) | 3000–5000 nm | Thermal imaging and gas detection |
| Long-wave infrared (LWIR) | 8000–14000 nm | Thermal cameras, temperature measurement and surveillance |
Compact laser modules primarily use near-infrared wavelengths.
An 808 nm laser is widely used for illumination, sensing, pumping,
medical equipment and infrared positioning.
A very weak red glow may sometimes be visible close to a high-power 808 nm source.
The 850 nm wavelength belongs to the near-infrared band.
It is commonly used in night-vision equipment, infrared cameras,
security systems, machine vision and industrial sensors.
Some people may notice a faint red glow directly at the output of a
high-power 850 nm source, but the projected beam itself is normally invisible.
The 905 nm wavelength is widely used in laser rangefinders,
LiDAR, distance sensors and detection systems.
A 940 nm laser is more difficult for the human eye to detect than an 850 nm laser.
It is frequently used in facial recognition, infrared sensing, surveillance cameras and covert illumination systems.
The 980 nm wavelength is commonly used in medical devices,
optical pumping, industrial processing and specialized sensing systems.
Choosing a laser module should not be based on color alone.
The following factors should also be considered:
1.Visibility requirements
Green lasers provide excellent visibility, while infrared lasers require a compatible camera or detector.
2.Target material and surface color
The contrast of the laser pattern changes with the color, texture and reflectivity of the target surface.
3.Indoor or outdoor operation
Bright sunlight can significantly reduce the visibility of a laser beam.
Outdoor applications may require higher optical power, a green wavelength or an optical filter.
4.Operating distance
Long-distance applications require suitable output power, beam divergence and focusing performance.
5.Beam pattern
Laser modules can produce dots, lines, crosses, circles, grids, parallel lines and other customized patterns.
6.Detector sensitivity
For infrared applications, the laser wavelength must match the spectral response of the camera, photodiode or sensor.
7.Operating environment
Temperature, dust, water exposure, vibration and continuous operating time
should be considered when selecting the housing and protection level.
Invisible infrared lasers require special care because the natural blink response
may not protect the eyes from an invisible beam.
A laser should never be viewed directly or through optical instruments.
The appropriate laser classification, protective eyewear,
warning labels and engineering controls should be selected
according to the wavelength and accessible emission level of the finished system.
Photex Laser provides customized dot, line, cross
and special-pattern laser modules for industrial and OEM applications.
Available wavelength options include:
We can customize the wavelength, optical power, module dimensions,
beam shape, fan angle, focus distance, operating voltage,
modulation mode, connector and housing structure.
Contact Photex Laser with your required wavelength,
working distance, beam size, output pattern and application environment.
Our team can help you select or develop a suitable laser module for your system.
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