What does 940nm mean?

Infrared Wavelength - 940 nm Explained

The 940 nm (nanometers) designation refers to a specific wavelength of light within the infrared (IR) spectrum. Infrared radiation is electromagnetic radiation with longer wavelengths than those of visible light, and it is not visible to the human eye. The IR spectrum is typically divided into several categories, with 940 nm falling into the near-infrared (NIR) band.

Properties and Uses of 940 nm Infrared Light

• Invisibility to the Human Eye: While 850 nm infrared light can produce a faint red glow, 940 nm is usually invisible, making it suitable for applications requiring stealth or where visible light is undesirable.
• Security and Surveillance: 940 nm IR LEDs are often used in security cameras to illuminate scenes that the camera needs to capture without drawing attention.
• Remote Controls: Consumer electronics, such as TV remote controls, commonly employ IR LEDs around 940 nm for wireless signal transmission.
• Biomedical Applications: IR wavelengths, including 940 nm, are sometimes used in medical treatments, such as phototherapy, due to their ability to penetrate skin and tissues.

Technical Aspects of 940 nm Wavelength

In optical engineering and design of IR systems, the choice of wavelength can greatly impact the performance. For example, longer wavelengths like 940 nm tend to have less interaction with silicon sensors and therefore might require more powerful light sources for equivalent sensor detection levels when compared to shorter wavelengths like 850 nm.

In summary, the designation of 940 nm refers to an infrared wavelength often chosen for its invisibility to the human eye and its applications in various fields where discreet illumination or communication is required.