Calculate number of modes incident on detect from black body

[C. Darwin]

Homework Statement

In an experiment to measure photon statistics of thermal light, the radiation from a black-body source is filtered with an interference filter of bandwidth 0.1 nm centered at 500 nm, and allowed to fall on a photon-counting detector. Calculate the number of modes incident on the detector, and hence discuss the type of statistics that would be expected.

Homework Equations

The Attempt at a Solution

I feel pretty lost with this question. I'm not even sure what is meant by MODES. Is it the different frequencies of the photons in the 499.05 to 500.05 nm range?

 

[weejee]

Isn't it something like "number of modes per volume"? Just the "number of modes" sounds meaningless to me, too.

 

[C. Darwin]

Yes it is the number of modes per volume. I think one of the issues I was having with this problem was that I didn't realize the peak of the black body was supposed to be at 500 nm, and that the filter was centered at the peak.