Hi. I am using a light meter with a sensor head that can detect from 200 to 1000nm wavelength. However, the meter has a unit of mW/cm2. The laser that I am trying to measure is around 5mW with the beam diameter of a bout 3/4 to 1mm. Do I just multiply the display power (mW/cm2) with the cross sectional area of the laser beam? This is strange because the reading from the meter is "nearly" correct but in mW/cm2; i.e. meter read 4.7mW/cm2. Please advice. Thanks.