Provide a valuable resource to your clients or customers by linking to this resource page. Just place the following link on your website.
700 nanometers (700 nm) is a wavelength at the deep red end of visible light. It sits close to the boundary where infrared begins. Light near this wavelength can look deep red, though visibility depends on brightness and your eyes. Many optical specs mention 700 nm because it marks the long-wavelength edge of the visible range.
read more about 700 Nanometers ...Visible light is often described as roughly 400 to 700 nm. 700 nm is at the long-wavelength end, which is why it is associated with red. Wavelengths longer than this enter near-infrared, which the human eye cannot see well. Some sources place the boundary slightly above or below 700 nm, but it is a common reference point.
Near 700 nm, light is used in some imaging, sensing, and illumination systems. Some medical and lab devices use red or near-IR light because it can behave differently in tissue than shorter wavelengths. Some remote controls and sensors use near-infrared just beyond the visible range. The exact effect depends on intensity and the device design.
Deep red LEDs can look dimmer than green LEDs at the same power because the eye is less sensitive in deep red. You may also notice that deep red light feels less glaring at night, which is why some devices use red indicators. A red filter test in eye care uses red light for a different purpose, but it is not necessarily 700 nm. Context matters for interpretation.
Most red LEDs used in daily products are safe at normal brightness. Risks rise with lasers or high-power emitters, where the beam can concentrate energy. Infrared is a special risk because you may not see it clearly even when it is intense. Use proper eye protection and safety labels when working with lasers or strong light sources.
It is typically considered visible deep red right at the edge. Infrared starts just beyond this range. The exact boundary can vary slightly by reference, but 700 nm is a common marker.
The human eye is less sensitive at deep red wavelengths. So even if a device outputs similar power, deep red can appear dimmer than green. Brightness perception depends on your eye's sensitivity curve.
Some exam devices use red light, but they may not specify the exact wavelength. Tests like the red filter test are about color filtering and alignment, not a specific 700 nm value. Device specs would list the wavelength if it matters.
Normal consumer red lights are usually safe. High-intensity sources like lasers can be harmful, regardless of wavelength. Always follow safety ratings for lasers and high-power emitters.
Computer vision syndrome. AOA. https://www.aoa.org/healthy-eyes/eye-and-vision-conditions/computer-vision-syndrome. Accessed March 30, 2026.
Eye Health Guidance for Screen Time. AOA. https://www.aoa.org/aoa/documents/healthy%20eyes/digital_eyestrain.pdf. Accessed March 30, 2026.
Computers, Digital Devices, and Eye Strain. AAO. https://www.aao.org/eye-health/tips-prevention/computer-usage. Accessed March 30, 2026.
Digital Devices and Your Eyes. AAO. https://www.aao.org/eye-health/tips-prevention/digital-devices-your-eyes. Accessed March 30, 2026.
Dry Eye. National Eye Institute. https://www.nei.nih.gov/eye-health-information/eye-conditions-and-diseases/dry-eye. Accessed March 30, 2026.