How Can I Accurately Measure Light Intensity After Polarization?

[ellion71]

Part of my independent investigation requires me to carry out an experiment, which when I graph results, would confirm Malus' Law.

I plan on using a bulb as my ambient source and two polarizing lenses. I will then measure the intensity of the light after polarization. Hopefully, if i graph the angle of the analyzing polarizer against intensity I will get a Cosine curve.

However, I am not quite sure on how to measure the intensity of the light after polarization.

Thanks in Advance
Any help/advice would be much appreciated.


P.S
My lecturer has suggested using a irradiance detector which measures in LUX but I am not sure how to convert a value in LUX to a value in W/m^2.

 

[kuruman]

You don't need to convert. The ratio of the intensity after the polarizer to the ratio of the intensity before the polarizer is all you need to know in order to confirm Malus' Law.