Access to eBooks is limited to institutions that have purchased or currently subscribe to the SPIE eBooks program. eBooks are not available via an individual subscription. SPIE books (print and digital) may be purchased individually on SPIE.Org.

Contact your librarian to recommend SPIE eBooks for your organization.
Chapter 31:
Quanta and Photons
By the Mid-Nineteenth century the wave theory of light was well established. One could thus consider relationships existing in a specified spectral region. In fact, the theorem of Gustav Robert Kirchhoff (1824 to 1887) considered the fraction of energy incident in a narrow spectral band on a cavity maintained at a given temperature. He showed that the ratio of the emission to the energy absorbed in that spectral band must be a constant, and that this constant represents an intensity distribution which is a universal function. Such a function is dependent only on the temperature and wavelength, and not on the size, shape, or material of the cavity.
Online access to SPIE eBooks is limited to subscribing institutions.

Back to Top