PPLN green 530nm laser

[Anthony P]

The holography will not end. I had just planned on learning enough to expand horizons by then. With HeNe I made a matchbox semi truck that turned out well, but my best work is a Star Wars action figure storm trooper. Everyone who has seen it is amazed. LaserGlow said they had some holography grade lasers with coherence length of >50meters. They are prohibitively expensive.
My good interferometer parts will be here Friday. I will attempt to check the coherence length of the PPLN being discussed here. Just casual observations I can say that it has a clean circular beam that is somewhat divergent. At aperture it looks about 1-2mm at 1m it looks about 12mm or so. Again, just casual observations. I hope to do some real tests this weekend.

 

[paul1598419]

The coherence length of a laser has nothing to do with its divergence. In fact, you need the beam to diverge in order to make the hologram anyway. The problem with making a full color one is that you have to make three holograms and they need to line up perfectly before you combine them into just one hologram. I had some very well made full color holograms in my collection that were pretty awesome, in my eyes. It is not a simple task to make a red, green and blue hologram of the same scene and combine them into one perfect hologram. One of the ones I had was of a circuit board with a magnifying glass that came out of the hologram and enlarged what looked like a part of the full color circuit board. I gave all my holograms to my daughter some time ago, but they got lost in the many moves she has gone through. Oh well.

 

[diachi]

The holography will not end. I had just planned on learning enough to expand horizons by then. With HeNe I made a matchbox semi truck that turned out well, but my best work is a Star Wars action figure storm trooper. Everyone who has seen it is amazed. LaserGlow said they had some holography grade lasers with coherence length of >50meters. They are prohibitively expensive.
My good interferometer parts will be here Friday. I will attempt to check the coherence length of the PPLN being discussed here. Just casual observations I can say that it has a clean circular beam that is somewhat divergent. At aperture it looks about 1-2mm at 1m it looks about 12mm or so. Again, just casual observations. I hope to do some real tests this weekend.

Spec sheet says 0.1mm at aperture. Between 4mRad and 8mRad divergence.

 

[aaronnoraa]

That reminds me of a hologram I saw in the 1990s. It was about 18" by 18" and was a forest and and pair of binoculars that extended out from the hologram about 10" You could walk up and look into the binoculars and see a nest in a tree branch with some baby birds in it. I could have ordered a copy for $250, but didn't do it. Wish I had. It was really something to see. I know exactly how it was made too.

This sounds amazing. Wish I could see something like that..

 

[paul1598419]

It was very amazing to see. But, I was a single parent at the time and just couldn't justify the $250 price tag. If I could get a copy now at that price I would jump all over it. There was a gallery of just holographic art when I first got into holography and for several years afterward. They even had some portraits that were just like looking at a person, only monochromatic. They were done with a ruby laser at a very short pulse width.