Dear Research Community,
I want to know how can I calculate %reflection from the intensity of He-Ne laser.
Thanks in advance
Dear David Chiu ,
'Fresnels equation' is the buzz-word...
https://en.wikipedia.org/wiki/Fresnel_equations
David Chiu , from the words about a laser, I guess that you want to measure the reflectance experimentally. In this case you need to measure power of the incident light and power of the reflected light. Divide the latter by the former to obtain reflectance as coefficient. I trust you know how to get this as percent.
Take care about the light reflected by the second surface. If it comes too close to the beam reflected by the first surface (a usual case), you can try to put a prism onto the second surface with immersion oil. With good refractive index match, this will decrease the intensity of the second reflection by orders of magnitude. Sometimes a silicon rubber can be used instead of oil (and prism). To measure at very small incident angles, increase the distance between the laser and the reflecting surface.
To calculate the Reflection of the Laser. Normally lambada/2 of the percentage of the laser composition. Then you had calculate the energy of the laser in the incident photons.
the line y = x is the point (y, x). the line y = -x is the point (-y, -x). Remember that each point of a reflected image is the same distance from the line of reflection as the corresponding point of the original figure. The line of reflection will lie directly in the middle between the original figure and its image.
Fresnel Equation is widely used. I also agree with Dr. Chukharev answer.