Search found 280 matches

by lobaz
Tue Nov 12, 2019 5:45 pm
Forum: Beginning Holography
Topic: Two issues - losing an object beam and spots on plate
Replies: 17
Views: 11210

Re: Two issues - losing an object beam and spots on plate

Antonio, I assume your object is diffuse, i.e., it breaks polarization. I also assume that lengths of the object and the reference paths are approximately the same, i.e., within the coherence length of the laser you use. You can check the amount of object light hitting the plate as Dinesh suggested,...
by lobaz
Tue Nov 12, 2019 5:25 pm
Forum: holoforum administration
Topic: Denial of Service Attack (more or less)
Replies: 4
Views: 7694

Re: Denial of Service Attack (more or less)

Thanks for solving the problem and keeping the forum alive!
by lobaz
Sat Nov 09, 2019 1:00 pm
Forum: Beginning Holography
Topic: Two issues - losing an object beam and spots on plate
Replies: 17
Views: 11210

Re: Two issues - losing an object beam and spots on plate

It is difficult to judge, but as Ed pointed out: the most likely reason is movement. It can be either movement of an optical component, which can be tracked by careful inspection of the setup. The other thing that can move is air - split beam setups are very sensitive to air currents.
by lobaz
Sat Nov 09, 2019 9:56 am
Forum: Beginning Holography
Topic: Current practical methods for printing CGH
Replies: 6
Views: 6727

Re: Current practical methods for printing CGH

I have no particular recommendation to the imagesetting device. About 20 years ago, you could find one in every medium size town. Today, they were largely replaced by CtP (computer-to-plate) technology. But imagesetters are still used in printing industry, for exampe in silkscreen printing or in die...
by lobaz
Fri Nov 08, 2019 3:28 pm
Forum: Beginning Holography
Topic: Current practical methods for printing CGH
Replies: 6
Views: 6727

Re: Current practical methods for printing CGH

Hi, Nana, as far as I know, there is no simple and affordable way. You can find someone from the printing industry still operating an imagesetter. It will "print" you a binary opaque (black) pattern on a transparent film. The imagesetters pixels can be approximately 10 um in diameter, mayb...
by lobaz
Thu Oct 24, 2019 4:48 pm
Forum: Off Topic
Topic: Anybody still here?
Replies: 19
Views: 13928

Re: Anybody still here?

I can confirm that soda is working hard to make his pulsed ruby perfect!
By the way, as far as I know, unixboy succeeded in making his pulsed ND-YAG; unfortunately, I think he cannot follow the forum from China due to government restrictions.
by lobaz
Fri Oct 18, 2019 4:19 am
Forum: Off Topic
Topic: Anybody still here?
Replies: 19
Views: 13928

Re: Anybody still here?

I prefer this forum to discuss more involved topics.
by lobaz
Sat Jul 06, 2019 9:08 am
Forum: holoforum administration
Topic: PM problem
Replies: 6
Views: 15908

Re: PM problem

admin_jsfisher wrote: Fri Jul 05, 2019 2:48 pm ...or it may be working as designed.
Who knows... Anyway, it seems everything is OK now. Thanks for keeping the forum!
by lobaz
Fri Jul 05, 2019 3:34 am
Forum: holoforum administration
Topic: PM problem
Replies: 6
Views: 15908

PM problem

Hi,
it seems something is wrong with PMs - there are two messages hanging in my outbox, one for Ed, the other for Dinesh. It seems they have not been sent, although at least Ed logged in since I wrote them.

Petr
by lobaz
Tue Jul 02, 2019 3:21 pm
Forum: General Holography
Topic: magnified hologram
Replies: 14
Views: 11077

Re: magnified hologram

So it will be magnified (not shrunk) if the reference beam diverges from a location on same side as object but farther away. If that location is twice as far from the plate as the object for instance, we will get 2x transverse magnification and 4x longitudinal. Maybe :) I always have to draw a few ...