Long-wave infrared (LWIR) refers to a specific range of the infrared spectrum. Infrared radiation is divided into three main categories based on wavelength: near-infrared (NIR), mid-wave infrared (MWIR), and long-wave infrared (LWIR). LWIR covers wavelengths typically ranging from about 8 to 15 micrometers (μm).
Key points about LWIR:
Wavelength range: LWIR corresponds to the longer wavelengths within the infrared spectrum, specifically in the range of 8 to 15 micrometers. These wavelengths are associated with thermal radiation emitted by objects at temperatures commonly encountered on Earth.
Thermal imaging: LWIR is often used in thermal imaging and infrared sensing applications. Objects at room temperature (around 300 Kelvin) emit radiation predominantly in the LWIR range. Thermal cameras designed to detect and visualize temperature differences rely on LWIR sensors.
Atmospheric absorption: LWIR radiation is less affected by atmospheric absorption compared to some shorter infrared wavelengths. This makes LWIR suitable for applications where the infrared radiation must pass through the atmosphere before reaching the sensor.
LWIR technology is used in various applications, including:
Thermal imaging Cameras: LWIR sensors are commonly employed in thermal cameras for applications such as night vision, surveillance, and industrial inspections.
Remote sensing: LWIR is used in remote sensing applications, including environmental monitoring, agriculture, and geological surveys.
Medical imaging: Infrared thermography for medical purposes often utilizes LWIR imaging to detect variations in skin temperature.
Materials absorption: Certain materials strongly absorb LWIR radiation, making it useful for detecting temperature differences in a variety of materials.
Understanding the characteristics of LWIR radiation is important in the design and application of infrared technologies, especially those related to thermal imaging and remote sensing. Different regions of the infrared spectrum offer unique advantages and are selected based on the specific requirements of a given application.