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Re: [Phys-l] A demo for biologists?



ludwik kowalski wrote:
wide laser beam - -> \ - - - leg 1 - - > / - - - > I
I ^ I
I I screen
I I
I I
\ - - - leg 2 - - > /

Upper slashed lines (in leg 1) represent semitransparent mirrors, lower slashed lines represent ordinary mirrors. Suppose a microscopic slide, partially covered with a transparent thin film, is introduced into leg 1. My expectation is that interference of two beams (observed on the screen), traversing the slide and not traversing the slide, will result in phase contrast. That demonstration (turning an invisible "phase image" into a visible "amplitude image," would be easier to understand than what happens in a phase microscope. Is there anything thing wrong with this idea?
Your layout uses two half mirror traversals for leg 1 and none for leg 2.

It would be simpler, cheaper (and more balanced) to arrange it like this
Michelson-Morley arrangement with one half mirror and
two front surface mirrors:

screen
I I I I laser beam - -> \ - - - leg 1 - - |
I I I I - leg 2

Seeing interference fringes requires no great effort.

Brian W