Radiometric Properties of Materials
DOI: 10.1117/3.798237.ch3
text A A A

Excerpt

3.1 Introduction and Terminology

When radiant flux is incident upon a surface or medium, three processes occur: reflection, absorption, and transmission. A fraction of the beam is reflected, another fraction is absorbed, and the remainder is transmitted. Transmittance τ is the ratio of transmitted power to incident power. Reflectance ρ is the ratio of reflected power to incident power. Absorptance α is the ratio of absorbed power to incident power.

Figure 3.1 shows an ideal geometric case, where the transmitted and reflected components are either specular (regular, in the mirror direction) or diffuse (scattered into the hemisphere). Figure 3.2 shows the transmission and reflection for real surfaces. Both spectral and directional properties are important.

© 2010 Society of Photo-Optical Instrumentation Engineers

Access This Chapter

Access to SPIE eBooks is limited to subscribing institutions and is not available as part of a personal subscription. Print or electronic versions of individual SPIE books may be purchased via SPIE.org.

Related Content

Customize your page view by dragging & repositioning the boxes below.

Related Book Chapters

Topic Collections

Advertisement
  • Don't have an account?
  • Subscribe to the SPIE Digital Library
  • Create a FREE account to sign up for Digital Library content alerts and gain access to institutional subscriptions remotely.
Access This Article
Sign in or Create a personal account to Buy this article ($20 for members, $25 for non-members).
Access This Proceeding
Sign in or Create a personal account to Buy this article ($15 for members, $18 for non-members).
Access This Chapter

Access to SPIE eBooks is limited to subscribing institutions and is not available as part of a personal subscription. Print or electronic versions of individual SPIE books may be purchased via SPIE.org.