Perhaps some of the laser experts out there wouldn't mind checking these calculations/assumptions. Your help will be greatly appreciated. Please answer me directly unless you believe it is appropriate to answer to the list.
The problem:
Given a 2 mW laser diode with a 651 nm wavelength and a 5mm aperture and a human eye very near the aperture, I calculated the irradiance on the eye as follows: .002 W divided by .385 cm squared, using 7mm as the area(human dilated pupil as the limiting aperture). Answer equals 5.19x10 to the -3 W/square centimeter.
Also, calculating the MPE for this particular laser, using Table 5 from Z136.1:
MPE=1.8(t to the 3/4)x 10 to the -3
t=0.25 seconds(aversion response)
MPE=6.36x10 to -4 J/square centimeter divided by 0.25
=2.5x10 to -3 W/square centimeter
Have I made some mistakes, or is the irradiance near the aperture really more than twice the MPE?
Can I assume the power of the laser(thus the irradiance) will be less than 2 mW at, say, 8 feet from the aperture? Thanks in advance for all help.