Picking up holography again after many years.

[The_Stranger]

LOL, I have used this, a table saw mitre, a plastic protractor, the reflection statement made by Ed....

But while we are on the subject, I would really play with Ed's statememt. This is all mute if your laser is not polarized in the correct direction.

And with that last statement lies the problem. I use the laser diode bought from integraf, haven't got a clue about the characteristics of that thing. I would love to play with a "bigger" laser, but that seems rather expensive, but I also wouldn't have a clue where to get a suitable one, since most information on the net comes from the states. (and buying one of those for a lot of money from overseas sounds extra expensive due to shipping and somewhat risky). And it might be a little to soon to take that step yet..

[JohnFP]

I look up the laser Integraf offers and it is polarized 100:1, so here is some helpful advice. Fun to play with anyway to see the different effects polarization has on reflectance.

Ok, first try to get the laser mounted such that the light is hitting the a piece of plain glass at 56 degrees coming from above (use the paper trick, its cheap).

Not sure how you are mounting your laser but attach it with a rubber band or something (even a spring cloths pin would work) such that you can rotate it. Now place a white card in front of the piece of glass where the reflected light off the front of the glass is hitting. Look at the reflection off the glass onto that white card. Now rotate the laser a little at a time and watch the reflection. There will be two spots (180 degress across from one another) that will reflect the least amount of light. When you find one of them, your laser is polarized in the correct direction for overhead lighting. Mark a dot on the laser at the tippy top so you can always set you laser up like this, again for over head lighting only. (you need to rotate the laser 90 degree if you come in from the side.

Now with the laser reflecting the least off of the glass as we found above, take the glas plate and ever so gently tilt it forward and backward until you see the least amount of reflecting light on the card again. When you get to the least amount of reflected light you will have your brewsters (as Ed mentioned). If done correctly you should see almost no light at all beging reflected.

Peace, have fun!

[JohnFP]

If you are using side lighting, then do all the same but come in from 56 degree from the side. You will have to stand the white card up to see the reflected light off the plate though.

When you get to the part to tilt, do not tilt top of plate but rather the far edge of the plate toward and away from the laser.

http://hyperphysics.phy-astr.gsu.edu/hbase/hframe.html
click
Light and Vision
then
Polarization

[The_Stranger]

Thanks JohnFP,

Since I am in an hotel at the moment, the experiments have to wait some days, but will certainly try them once I am home and have some time.