- #1

duchuy

- 79

- 3

- Homework Statement
- Light diffraction and phase

- Relevant Equations
- g(t, x) A.sin ( w ( t - x/c ) )

Hi, I need help finding the phase difference between the two rays converging at F'.

I was given this figure, the distance between the lenses is 10cm, the thickness of the lense is 1micrometer and the indexes are on the figure. The light is a laser in which lamda = 500nm.

I tried to write down the two expressions of the two phases of each ray, and I found :

phi1 = (2pi x . 1,1) / 500x10^-9 and phi2 = (2pi x . 1,35) / 500x10^-9.

So i don't understand in this case is x a constant or a variable and how to do I calculate the phase difference of these two rays because when i tried to calculate phi2 - phi1 I found a really weird anwer. And also, is the unit of phase difference rad/m?

And then with the answer, how would I know if it's a constructive or destructive interference?

Thank you all for your help cheers!

I was given this figure, the distance between the lenses is 10cm, the thickness of the lense is 1micrometer and the indexes are on the figure. The light is a laser in which lamda = 500nm.

I tried to write down the two expressions of the two phases of each ray, and I found :

phi1 = (2pi x . 1,1) / 500x10^-9 and phi2 = (2pi x . 1,35) / 500x10^-9.

So i don't understand in this case is x a constant or a variable and how to do I calculate the phase difference of these two rays because when i tried to calculate phi2 - phi1 I found a really weird anwer. And also, is the unit of phase difference rad/m?

And then with the answer, how would I know if it's a constructive or destructive interference?

Thank you all for your help cheers!