ISO 20473:2007

Overview

ISO 20473:2007, "Optics and photonics - Spectral bands," specifies a standardized division of optical radiation into spectral bands for use in optics and photonics. The standard defines wavelength-based band limits (with corresponding approximate frequency, wavenumber and photon energy values) and clarifies terminology - notably restricting the term “light” to visible radiation (380 nm to 780 nm). ISO 20473 excludes lighting, telecommunication applications and occupational hazard protection.

Key topics

• Spectral band definitions: Wavelength-based band limits are given in Table 1. Examples (as specified) include:
  • Extreme UV (EUV): 1–100 nm
  • Vacuum UV (VUV): 100–190 nm
  • Deep UV (DUV): 190–280 nm
  • UV-B: 280–315 nm
  • Near UV / UV-A: 315–380 nm
  • Visible (VIS, “light”): 380–780 nm
  • Near IR / IR‑A: 780–1 400 nm
  • IR‑B: 1 400–3 000 nm
  • Mid IR (MIR): 3 000–50 000 nm
  • Far IR (FIR): begins at 50 000 nm
• Inclusive band limits: Band edges are included in both adjacent bands (i.e., overlaps at boundaries).
• Vacuum vs. medium: Relations among wavelength, frequency, wavenumber and photon energy are strictly valid for vacuum; when relevant, the medium’s refractive index must be considered.
• Terminology note & rationale: Annex A explains the choice of the 380 nm boundary between UV‑A and visible for optics and photonics (aligned with ophthalmic practice and material considerations).

Applications

ISO 20473:2007 is practical for professionals who need a common, unambiguous spectral vocabulary and band delimitation in optics and photonics contexts:

• Optical system and sensor design (spectrometers, detectors, imaging systems)
• Optical component specification and testing (filters, lenses, coatings)
• Photonics R&D, laboratory reporting and data comparability
• Product datasheets, calibration protocols and technical documentation
• Education, standards alignment and interoperability among manufacturers and test labs

It is not the reference for lighting engineering, telecom wavelength allocation, or occupational optical‑radiation safety - those domains use different band definitions.

Who uses this standard

• Optical and photonics engineers
• Manufacturers of optical components and instruments
• Calibration and test laboratories
• Standards committees and technical writers preparing product specifications

Related standards

• ISO 13666 (ophthalmic optics vocabulary) - referenced for eye‑related effects
• IEC 60050‑845 / CIE Publication No. 17.4 - lighting and lighting vocabulary, alternative definitions (e.g., UV‑A boundary sometimes given as 400 nm)

Keywords: ISO 20473, spectral bands, optics and photonics, wavelength ranges, UV visible infrared, spectral band definitions.