wavelength radiation
 

hi guys
i want to simulate radiation that is has different transmissivity in wavelength in long wavelength it has transmissivity=0 and in short wavelength it has transmissivity=1 i set 2 bands one 0-3 and other 3-100 and for first one set trnsmissivity=1 and the second zero, but it give me wrong answer i don't know why? and what can i do?