Hi MANG2004, qb+Gjgp
F_~A8y
I am curious about your calculation, too. Plus, the definition of σ refers to 1/e^2 width not the FWHM. Even your calculation/defintion is correct. I have a doubt that it will work when the specualr incident ray angle is not normal......... KdC'#$
e,T^8_>
For thsoe who knows it better, please have some input. I am rather curious, too!! Thanks!!