Planck2.m

compute spectral radiance of ideal blackbody radiator

Planck2 computes the spectral radiance of an ideal blackbody radiator in units of W/m^2/sr/Hz as a function of the frequency in Hz and temperature in Kelvin.

The temperature T must be specified as a scalar (single value). The frequency nu may be specified as either a scalar or a vector. If nu is a vector, the function returns a vector of spectral radiances (one for each wavelength). If you want to evaluate the spectral radiance at a large number of frequencies, it is far more efficient to create a vector of wavelengths and call this function only once rather than making a separate call for each wavelength.

Reference: Wikipedia article entitled "Black Body", URL= http://en.wikipedia.org/wiki/Black_body_radiation

REVISION HISTORY

Version 2.0, 4-3-2007: Modified code to use the first three terms of a Taylor expansion for exp(x)-1 when x is less than 4.9e-6. For x < 4.9e-6, the three-term Taylor expansion is more accurate.

Version 1.0, 3-22-2007: Initial version.