Spectralon is a type of highly reflective diffusing material often used in optical research and calibration. It is made up of a solid polytetrafluoroethylene (PTFE) material that has been doped with a highly reflective pigment. Spectralon is known for its exceptional reflectance properties, with a nearly Lambertian reflectance profile across a wide spectral range, making it ideal for applications such as radiometric and photometric measurements, as well as in the design and testing of optical systems. Its high reflectance and diffuse properties make it a popular choice for calibration standards and targets in spectroscopy, remote sensing, and other optical measurements.