Refraction optics project help

[Endy0816]

Have this sort of setup right now. Pane of glass with led light passing through it. Droplets of different liquids to test emission. Is it possible to get the light to come out more vertically from any droplets instead though?

[swansont]

It's not clear where the light source is. "Vertically" in your picture is parallel to the glass.  

[Endy0816]

1 hour ago, swansont said:

It's not clear where the light source is. "Vertically" in your picture is parallel to the glass.

Good point. Light is entering the glass at the top of the picture via an led.

Would like the light to be headed more perpendicular or towards the camera after getting to the drops.

Want the liquids could have a more uniformly glowing look to them.

Edited December 12, 2018 by Endy0816

[swansont]

If the light is in the glass, then it's being a waveguide, and some light should couple out through the drops (so you need to be looking on the same side as the drops). That process is called frustrated total internal reflection or evanescent wave coupling  (which can be used to couple light between optical fibers), and it depends on the index of refraction of the drops vs the glass. Possible modifications would be putting a third material in between the drop and the glass. (I've seen frustrated TIR with scotch tape on plexiglass) or use a different transparent material (e.g. plexiglass or other transparent plastic, or some other kind of glass with a different index)

[Endy0816]

9 hours ago, swansont said:

If the light is in the glass, then it's being a waveguide, and some light should couple out through the drops (so you need to be looking on the same side as the drops). That process is called frustrated total internal reflection or evanescent wave coupling  (which can be used to couple light between optical fibers), and it depends on the index of refraction of the drops vs the glass. Possible modifications would be putting a third material in between the drop and the glass. (I've seen frustrated TIR with scotch tape on plexiglass) or use a different transparent material (e.g. plexiglass or other transparent plastic, or some other kind of glass with a different index)

The mention of a third material was very helpful. Thank you. Was a bit dim with just scotch tape but trying plastic on top of oil lit up nicely.