# Wave Plates

1. Aug 2, 2011

### fermatsenigma

If we put two identical quarter-wave plates together what will be the resulting plate? How would it be different from one of the quarter-wave plates?

2. Aug 3, 2011

3. Aug 3, 2011

### clem

If you put them in series with the axes aligned, you will get a half-wave plate.

4. Aug 3, 2011

### xts

Are you sure? Have you ever tried it? Putting in series? With 1mm distance between them? Or with just a small grain of dust between them?

Y33t's question about meaning of 'together' was not so trivial...

5. Aug 4, 2011

### clem

Why would a distance between them affect the phase difference?

6. Aug 4, 2011

### y33t

PD < wave1 < wave2

PD: propagation direction

Assume all axis are aligned, wave1 and wave2 are seperated by a finite distance of d (origin of wave2 is d length right to wave1 in the PD). wave2 will travel more than wave1 in the direction of PD to reach any target along this path thus there will be a phase delay between these two waves. If there exists a target along the PD these waves will collapse and form an interference pattern on the surface. It's a modified version of the Michelson Interferometer.

7. Aug 4, 2011

### xts

Because of reflections.
If two plates are are not glued together with immerse fluid you have two additional reflecting planes in the middle.

8. Aug 26, 2011

### andonrangelov

This is the way to build a zero order wave plate, so you may have a half-wave plate or a zero order quarter wave plate. Zero order wave plate has better properties then the wave plate.
Bye the way very good question and very proper time to ask it Aug2-11