Wavelength Range

Physicians who apply light in phototherapy or vision science classify the whole light spec­trum (i. e., from 100 nm to 1000 pm) based on its major mechanism of interaction with bio­logical cells and tissues. In particular, light spectral ranges are described as: ultraviolet (UV) light—UVC, 100-280 nm; UVB, 280-315 nm; and UVA, 315-400 nm; visible—400-780 nm (violet, 400-450 nm; blue, 450-480 nm; green, 510-560 nm; yellow, 560-590 nm; orange, 590-620 nm; and red, 620-780 nm); infrared(IR) light—IRA, 0.78-1.4 pm; IRB, 1.4-3.0 pm; and IRC, 3-1000 pm. However, physicists who consider light’s interaction with and propaga­tion in a biological media (atmosphere, ocean, etc.) classify light spectrum as UV (100­400 nm), visible (400-800 nm), near IR (NIR) (0.8-2.5 pm), middle IR (MIR) (2.5-50 pm), and far IR (FIR) (50-2000 pm). Presently, as light is more and more widely and effectively used in medicine, both classifications and terminologies are in use in the biomedical optics world. For example, because of a great success in tissue spectroscopy and imaging in the near infra­red range the term NIR is often used now by physicians. A current interest and future perspec­tive of the terahertz range of electromagnetic radiation in biomedical applications is the spreading of the light wavelength range used in medicine to the 2000 pm that physicists use.