Tag: Lasers

Dead hologram controller

Ugh. I went to power up the table on Saturday and discovered the main controller wouldn’t come on.

At first I thought the laptop had frozen (it doesn’t this every once in a blue moon) but no, it was running just fine.

Poking around under the table revealed a slightly melted fuse cover on the main controller and a fuse with no wire at all.

The recent electrical storms had apparently tried to toast the controller.

After purchasing some new fuses I found that the recent electrical storms had succeeded in frying the controller. As soon as I turn it on the fuse blows in a spectacular way. Short in the transformer? That’s what I’m hoping.

Table testing Hades

For what seems like forever now, I’ve been working on developing a DCG process for myself that I could use when making white-light copies of my silver masters.

After some inconsistent results I stripped the table top of all components and set up an interferometer to see how stable the table was.

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Continue reading Table testing Hades

Holography Labcast

I don’t know how often I’ll do these but I had the urge to record what I was doing in the lab.

I’ve been trying to get good results with the coherent 315 laser and VRP-M film and haven’t had any luck. In each case where I’ve gotten any kind of image, it’s been extremely dim.

Unfortunately I found that my shutter was causing a full seconds worth of ringing in the table and had to build a new shutter. That was completed yesterday and this morning I’m doing some more exposure and development tests.

My apologies for the sound quality. Next time I’ll have to make sure the microphone is closer to me at all times.

Without further ado, here’s my labcast.

Let me know if you’d like me to do more of these.

Interferometry in Green

Well, it turns out that one of the problems I was having with my green laser and the VRP-M film is my shutter.

image

When it opened it set the table to ringing for at least a full second.  My 2-4 second exposures were incredibly dim because they were getting fogged for the first second.  I found this out after setting up an interferometer (shown above, click for a larger picture) opening and closing the shutter while it was going.  The fringes really moved when the shutter closed but as no light would have been reaching the film, I didn’t care about that.  Have it shake the table when opening was a problem though.

I tried all sorts of things to improve the isolation of the shutter and damp the vibrations it was putting out but in the end I had to give up and make a shutter from scratch.

I took a panel meter and attached a multi-layered piece of aluminum foil and used that reflect the incoming beam and create a beam dump on the inner surface of the meter housing.  Painting the whole thing black created a nice little box to keep the beam in.

After putting a couple of beads of silicone where the meter arm rests against the coil I ended up with a nice quiet shutter that didn’t disturb the fringes at all.

It’s being put through its first hologram-making test right now.

My own flying death machine

I don’t have one of these babies yet but you can bet they’ll be on my Christmas list.

Laser tag is sweet. R/C helicopters are sweet. When you combine the two only good things can happen. That’s why I’m pretty amped about the news that a Chinese toy maker has armed its new R/C chopper with an IR transmitter and sensor, allowing for two to have laser dogfights in midair. If one gets hit, its power gets cut, sending it crashing to the ground. Cold blooded!

UK military targets civilians

Oops.

IT was not quite a Star Wars death ray, but air force Top Guns accidentally focused high-powered lasers on to a civilian car in May this year – potentially endangering the eyesight of peaceful earthlings.
RAAF F/A-18 fighters from the Williamtown base north of Newcastle were conducting exercises near the NSW mid-north coast town of Forster when the incident happened.

The pilots thought their laser targeting system was turned off for the training flight.

Unfortunately it wasn’t and the powerful light beams, known as class four lasers, were shone twice on to a road intersection for a total of 43 seconds.

Guys, remember to put your equipment into O.F.F mode first.

Graffiti by laser

I’d seen mention of this group before but never a description of how their laser tagging actually works.  Until I read the article in the NYT that is.

As Mr. Powderly neared the museum’s entrance, he jumped off the cycle and pointed it toward a bare stretch on a garage door across the street. Mr. Roth pulled a laser pointer from his pocket, and as he moved the laser’s green dot across the wall, a line of what looked like thick, drippy paint lit up its surface, roughly following the motion of his hand.

This actually sounds pretty darn cool.

Joining the crowd of cyclists, Mr. Powderly followed them as they moved through the honking streets of Brooklyn. In search of a spot to project their graffiti, they settled on the handball courts of McCarren Park in Greenpoint.

Mr. Powderly positioned the cycle to face the court’s gray concrete wall. Within a few minutes, someone had drawn a detailed sketch of a bicycle, and another person had traced an outline of an American flag.

Back in the lab

You ever look back at something you did months ago and wonder, "why did I do that?"

I did that this evening with the controller that I’ve got in my lab.

I’m starting work on another hologram for a professor at A&M and needed to do a bit of maintenance on the table. Strange, but every time a new hologram request from her comes in, there’s something that needs doing in the lab before I can get started.

This time the HEPA fan wasn’t shutting off during an exposure and the table light sensor wasn’t working.

It turned out with the HEPA fan that somehow I’d wired up the relay connection with an additional 5v going to it. I have no idea why I did that. Fortunately it just caused the controller chip on that port to heat up (and not work) but didn’t blow anything. Odd that it was working for a while and then just stopped.

The light sensor just turned out to be a loose connection at the junction between the table wiring and the controller wiring. Gremlins.

I also found a problem with the holocontroller software not always shutting off the fan and fixed that.

Now I just need to straighten up the lab, prep some film, paint the subject and shoot. All tomorrow morning.

Dance for me, little atom!

Do they wear dancing costumes?

Reuters reports that NIST has developed what may someday become a building block for quantum computing.

Suspended in laser light, thousands of atoms pair up and dance, each moving in perfect counterpoint to its partner. Porto’s team isolated pairs of atoms in a lattice of light formed by six laser beams all fixed on one point, suspending the atoms in a uniform pattern. "There is no container. It is levitated by the laser beams."

Continue reading Dance for me, little atom!