[Laser] Can anyone explain what a Steradian

[Paul Cianciolo]

Hello Folks,

I was wondering if anyone can explain what a steradian is?  I can look up
the formula no problem but conceptually I have a problem.

For instance

IR diode one has a 1/2 power beamwidth of 40 degrees and has 5 milliwatts
per steradian.

Another diode has a 1/2 power beamwidth of 10 degrees and has 50 or 100
milliwatts per steradian.

Both draw the same current.

Can the steradian rating be thought of as a intensity per given area?  Is it
that simple,  so as a higher mW/sr  would be more intense?
So if the power consumed by each diode is the same, the only way this could
be accomplished is through beamwidth??

Thanks so much

PaulC
W1VLF