Thin Film Interference Patterns

[jegues]

Homework Statement

See figure attached.

Homework Equations

The Attempt at a Solution

Not too sure how to do this one.

I tried thinking about what it was doing before the air was replaced with the liquid.

With air,

The first reflection would have no phase shift (glass index to air index), the second reflection would have a phase shift of pi (air index to glass index) so overall we a have a phase shift of pi.

How do I obtain an expression about the interference pattern from this?

With the liquid instead of the air, we will still have a phase change of pi but the wavelength will change since the index of the liquid is 4/3 not 1.

Any ideas?

Thanks again!

 

[ehild]

At what thickness values do you get destructive interference?

ehild

 

[jegues]

At what thickness values do you get destructive interference?

ehild

I have no clue. How do I go about figuring that out? I thought the type of interference I had was determined by the resultant phase shift (if any) of the 2 reflections.

Can you explain?

 

[ehild]

I thought the type of interference I had was determined by the resultant phase shift (if any) of the 2 reflections.

Yes, an the phase shift inside the wedge is 4pi times the thickness.

ehild