Query on use of prism in delayed choice quantum eraser experiment

[Steve4Physics]

TL;DR Summary

Query on use of prism in delayed choice quantum eraser experiment

Hi. I’ve seen a number of schematic diagrams for the Delayed Choice Quantum Eraser experiment. Some include a prism to make the two idler photon paths diverge.

However, the prism is shown refracting the ‘idler rays’ in a way which contravenes Snell’s law. E.g. see prism marked ‘PS’ (not the Glan-Thompson prism) here:

(from https://en.wikipedia.org/wiki/Delayed-choice_quantum_eraser)

Is this a mistake or have I misunderstood something? Thanks.

 

[Drakkith]

However, the prism is shown refracting the ‘idler rays’ in a way which contravenes Snell’s law. E.g. see prism marked ‘PS’ (not the Glan-Thompson prism) here:

Hmmm. I doubt the prism in the diagram is supposed to show the actual path of light in the experiment.

 

[Steve4Physics]

Hmmm. I doubt the prism in the diagram is supposed to show the actual path of light in the experiment.

Yes. It seems that part of the diagram is a bit of a 'bodge'. But the rest of the diagram seems OK. But I've found similar diagrams showing the same thing, so it's very puzzling.

 

[Drakkith]

No one is worried about Snell's law when they're throwing shapes and lines into powerpoint.

 

[Steve4Physics]

No one is worried about Snell's law when they're throwing shapes and lines into powerpoint.

I guess so. But it's much more than a minor misjudgement of angles.

And I noticed another mistake in the diagram. The ray paths through the Glan-Thomson prism (just after the SPDC non-linear crystal) are wrong.

Maybe I'm just being too picky!

With a bit of searching (using Google Images) I've now found a diagram which appears correct. I’m not sure about copyright so here's just the link:
https://www.researchgate.net/public...-delayed-choice-quantum-eraser-experiment.ppm