Saturday, February 24, 2007

Holographic Dreams

I had a strange dream last night.

Ken and I flew to Venezuela -- which was, in my dream, a sort of large tropical flea market. I found a display of holograms, and bought one that depicted a shoe. But when you turned the hologram to look at the shoe from different angles, it actually changed subtly, a very old work boot morphing into something modern as you rotated it. I decided, in my dream, that I was going to start collecting holograms. Then the dream got weirder, something about our bedroom being full of flies, but I woke up thinking about holograms.

Back in the early nineties you used to see decorative holograms for sale more often. I had one of a peace symbol that I wore as a necklace, and another one of space-walking astronauts, mounted on a little plastic stand, that sat on my dresser. These days it seems the novelty has kind of worn off, and you only see them on credit cards or as stickers on expensive products, verifying their authenticity.

Remembering my peace symbol and my astronauts, I thought maybe I really would start collecting holograms. I'm sure you can still order them off the internet, at least... Although that does take a bit of the fun out of collecting.

When I was in high school, some people I knew made their own holograms as an independent research project (they got a science credit for it.) I remember being impressed by little glass plates with 3-D coins on them, and by the laser they had set up in sandbox, on a concrete block that, according to the teacher, had its own foundation independent from the rest of the school, to minimize vibrations. These days I work in a laser lab, on, actually, the third floor of our building. The optical tables we use are supposed to be low vibration, if you use the built in hydraulic support system for the legs, but our tables are decades old and the hydraulics don't work anymore. I think my high school had a nicer set-up.

Our advisor has another lab, mostly separate from the one Ken and I work in, which is actually called the "holography" lab. But the holograms they make aren't like the ones I used to buy. They have more in common with DVDs, using a laser to store information and then retrieve it later. But they probably could make a picture of a coin, and I started thinking... Maybe I should ask them to show me how. I mean, will I get a chance again?

So that got me searching for "make your own hologram" kits. Turns out there are a few around these days. I don't have to bug the guys in the holography lab after all.

The only problem is, I think their holograms, like the ones you can make from these kits, would be viewable only in laser light of the same color as the laser used to create them. The kind of holograms I dreamed about collecting are embossed "rainbow transmission" holograms, apparently. All I really know about them is what I just read here. But they are certainly harder to produce, which is why they make good security stickers.

Also unfortunately, as far as I know you couldn't really make a hologram like the one I dreamed about, which morphs as you rotate it. Holograms are generally produced by shining a laser beam on a small object that is physically present. In the case of my astronaut hologram, it was almost certainly some plastic models of astronauts -- that's what they looked like. You can't combine images of different objects onto one hologram -- although you can record multiple holograms on the same piece of film, to be viewed with different colors of light.

So my dream can't exactly come true, even with a home hologram kit, or a whole holography lab.

There are other things holograms can't do. You can't make "true color" holograms that look like photographs except in 3-D, at least not in normal light. You may have seen something like this on a movie poster, but it's not a hologram. It's a "lenticular" poster. This is a completely different process that just makes different parts of a normal image visible from different angles. In general, the secret to making things look 3-D is to make each of your eyes see a slightly different image. But lenticular posters can hold a dozen different images, each visible from a different angle, so that not only can they look 3-D from different positions, they can even move or morph as you walk by. Any image you can print on paper can be used for this technique, physical models not required. So it's actually a more impressive and somewhat more useful technique than real holograms. But not as futuristic. Real holograms look three dimensional because they reproduce the light reflected off of actual three dimensional objects. Whereas lenticular images can show you only a dozen different angles on a scene, a hologram, like a real object, produces an infinite range of views.

What about holograms projected into empty space, like Princess Leia in Star Wars? Also not possible, unfortunately.

About the closest you can come is this arcade game, also from the early nineties. I played it. You really could reach in and put your hand "through" the characters.

But, as that Wikipedia link says, it was only an optical illusion, done with mirrors. Like the "mirage bowl", I guess. (My brother had one of those). The video game's images appeared only inside a sort of box, and couldn't be projected out into the room, the way R2-D2 projects Princess Leia.

More Star Wars-ish technology might be on the horizon, though. A Japanese company has a device that makes air glow in 3-D patterns. Again, not a hologram, but possibly much cooler. It seems to be sort of similar to the kind of "laser etching" used to create 3-D images in these crystals, only using the air itself as a medium. But the air will only keep glowing as long as they lasers are on, and apparently makes quite a lot of noise as it "explodes" from the heat, whereas once you burn a hole in the crystal, the hole stays.

I love this stuff. I can totally see myself accumulating a huge collection of cheesy 3-D toys and jewelry and posters. I'd also want to collect "Magic Eye" stereograms, including animated ones like the ones I linked to a while ago, and 3-D comics that you view with glasses, and probably Viewmaster slides -- I had one of those when I was a kid too.

Monday, February 19, 2007

February Poem

Street Cries

When dawn's first cymbals beat upon the sky,
Rousing the world to labour's various cry,
To tend the flock, to bind the mellowing grain,
From ardent toil to forge a little gain,
And fasting men go forth on hurrying feet,
BUY BREAD, BUY BREAD, rings down the eager street.

When the earth falters and the waters swoon
With the implacable radiance of noon,
And in dim shelters koils hush their notes,
And the faint, thirsting blood in languid throats
Craves liquid succour from the cruel heat,
BUY FRUIT, BUY FRUIT, steals down the panting street.

When twilight twinkling o'er the gay bazaars,
Unfurls a sudden canopy of stars,
When lutes are strung and fragrant torches lit
On white roof-terraces where lovers sit
Drinking together of life's poignant sweet,
BUY FLOWERS, BUY FLOWERS, floats down the singing street.

- Sarojini Naidu

Tuesday, February 13, 2007

We Have Liftoff

Click on the picture. Watch the animation. Then come back.

It's so hard to explain what this little animation means. Just know that it took years of blood sweat and tears to achieve it, mostly Ken's, but mine too, this last year or so. A lot of the saga I described here.

This is our magneto-optical trap. Being launched upward. The things on the sides are the magnetic coils that help hold it up. They are six centimeters in diameter, which should give you a sense of scale. We just need to be able to launch atoms a little bit higher than the top of the coils, because we can put our cavity right above them. This is the whole reason we designed these smaller coils, so that we wouldn't need to launch so high.

The atom cloud actually expands as it rises, out of the cooling beams. The beam we use to light it up so that we can see it is narrow, so you all you see is a narrow, pencil shaped slice out of the cloud as it expands, like the core of an apple. That's why it looks long and narrow toward the top.

These results don't mean we're done. First of all, we might want to cool the atoms a little more, so that they don't expand so much, so fast (although there is plenty of density up there, even as it is.) We are actually doing a slower launch, so that they slow to a halt just at the top of the coils and then fall back down. The slower launch takes longer, so the atom cloud has expanded more when it gets up there, which is why we might want the additional cooling. Also, we need a way to hold the atoms there, once we get them there. We already know how we're supposed to do that. It's called a "FORT" or "Far Off-Resonance Trap." It's easy in theory -- just shine a really strong, really tightly focused laser beam on the atoms, and that should hold them in place for the few milliseconds we need. Unfortunately we haven't made it work in practice yet, at least, not that we could detect. Finally, we need to actually build the cavity and put it in there. We've already built a couple of cavities for this thing, but for various reasons none of them is suitable for what we're trying to do now.

But still, that little blob in that animation looks a little bit like a light at the end of the tunnel.

Saturday, February 03, 2007

Links, Life

Yeah, I missed a week. Here's the thing, I'm really, really busy right now. This post is gonna be half links and half life update, cause those are the laziest kinds of posts (except for Bears-related photos that I upload without further comment, which is the laziest kind of all.)

Life update first: my two classes are kinda kicking my butt. It's been a year or so since I've taken a class, and the last one was taught by my advisor, who thought time in the lab was more important than getting the homework done anyway. It's been four years since I've taken one like my GR class, with twenty students, and homework problems from the end of the chapters due weekly, and midterms and finals and real grades. Just going squeezing the classes into my work days is hard. We're actually making a little progress with the MOT (I said I'd put up pictures of the launching we've done here, and I will, whenever we get the data off of the non-internetted computer it's stored on) but sometimes I'm not there when I'm needed. And when I am, days full of MOT work and school work are very full indeed, long and exhausting. Meanwhile the gyroscope project is sort of in suspended animation as we try to figure out what exactly needs to be done next. With no deadline attached to it, it has slipped to the bottom of my priority list. I am, however, writing a summary of our group's work on this stuff so far, which will probably become my thesis proposal, but which does have a deadline because it's supposed to be published as the text to accompany a talk my advisor gave.

Just writing about all that makes me feel as if I should be doing something more productive than blogging.

But I'm getting an intimidating backlog of links to post and comment on, so let me at least put a few of them up.

In particular, I've come across lot of related stuff about the suburbs, politics, and religion lately.

Slacktivist says the reason we're at war in Iraq is that our urban schools suck. Actually, he just says it's why we're not able to cut down our gasoline use. But we're at war in Iraq at least partly because we're so dependent on foreign oil, that's what makes the region so strategially important. We're dependent on foreign oil because everybody drives rather than taking mass transportation. But many people can't take mass transportation because they live in the suburbs. Why? Because that's where the good schools are.

He also has a powerful argument that the war in Iraq can't be "won" because it was not in our interest to begin with. If we were to invade Canada, what would it mean to "win"? Assuming we succeeded in taking down their government, what would we do then? Occupy Canada? Why would we want to do that? And for how long? Because there would be no reason to invade Canada in the first place, victory is undefinable. Same in Iraq. If there had been WMD to capture, we could've declared victory when we captured them, but since there were not, and since Saddam's government was not uniquely bad -- we have no reason to expect the next one to be better, if we pull out -- how do we know when we've "won"? (And if the real goal was to destabilize the middle east lest it unite against us? Then the war can never be won until we turn the middle east into Canada. So long as they have a significantly different culture and different values than us, some of our leaders will see their unity and prosperity as a threat.)

Meanwhile, back in the suburbs, Chris Hedges says that the reason the country is so polarized by religion is "suburban despair." He says "A terrible distortion and deformation of American society, where tens of millions of people in this country feel completely disenfranchised, where their physical communities have been obliterated, whether that's in the Rust Belt in Ohio or these monstrous exurbs like Orange County, where there is no community. There are no community rituals, no community centers, often there are no sidewalks. People live in empty soulless houses and drive big empty cars on freeways to Los Angeles and sit in vast offices and then come home again."

I think my "radically" Christian, suburban mother (who reads this blog, by the way-- hi, Mom) might actually agree with his argument, if not the conclusions he draws from it. She grew up not in the suburbs but in a small country town, and laments the loss of "community" every day. She does not find the daily grind of work, commute, TV, commute, work fulfilling either. When people begin to feel their lives are meaningless, religion gives them meaning. I think that is probably the definition of religion.

But I want to own my own home and have a couple of kids and make enough money to buy fancy digital toys and take vacations, too. Almost everybody wants that stuff, especially the people who actually live the furthest from the suburbs, in decaying inner cities and half abandonded rural towns. I think the problem is, what happens when you actually get all that? When you have nothing left to strive for, really? When you've achieved all your ambitions, what gets you out of bed in the morning then? That's the problem people "trapped" in the surburbs have. And that's why many of them turn to religious activism, to give them a purpose, a cause, a mission.

Of course, they also have the leisure and resources to pursue such a mission, which someone less successful, just struggling to make a living, doesn't have. That may be the other reason a lot of this comes out of the suburbs.

I think Hedges (who wrote War is a Force that Gives Us Meaning, a book that I found incredibly moving, and who is a graduate of Harvard Divinity School) is more on the money than Tom Frank (who wrote What's the Matter With Kansas). But in another article of his I think he makes the same mistake that Frank did, not taking the convictions of the people he's writing about seriously enough. I mean, I think that a lot of environmental activists are motivated by basically the same thing. They need a mission, and saving the world is a compelling one. But that doesn't mean the earth doesn't actually need saving. It does. And likewise, just because anti-abortion crusaders are motivated part by their need for a mission, doesn't mean they don't have a point. We're a hyprocritical society, aware that nothing magical happens at the moment of birth to turn worthless "tissue" into a priceless "child," and yet refusing to admit it, refusing to deal with the ambiguities or the moral queasiness they bring with them.

So long as we keep in mind that understanding people's motivations doesn't excuse us from taking their messages seriously, I think that kind of understanding is really valuable, and I still really respect Chris Hedges. I also think he's right that the divisions on some of these passionate issues could ultimately tear our society apart, and that some of the less rational religious types, like those obsessed with the "end times", seem to want it that way. And that does scare me some.

But my final link is proof that some people are anti-abortion and pro-environment, believe it or not. Crunchy Conservatives buy organic food and homeschool their kids, wear Birkenstocks and go to Bible study groups. The New York Times says it's "a kind of across-the-board rejection of modernity [...] Crunchy cons disapprove of abortion rights, same-sex marriage, illegal immigrants, public schools, secular liberals and mothers who work outside the home. But they don't like Wal-Mart, McMansions, suburbs, pollution, agribusiness or processed foods, either." I think I could like and even admire people like this, hard working and sincere in living their convictions, but not agree with them. I'm not on board with the rejection of modernity part. I like pop culture and I like technology and I like the idea of women working outside the home. And I like cheap food, and I like government social services, because self-reliance would only work if the world were fair. I'd much rather live in the modern world than fifty years ago or a hundred years ago or more, and I'll resist anyone who tries to turn back the clock.

But still, I respect these "Crunchy Cons," who manage to be both left wing and right wing nuts at the same time, more than people who are merely one or the other.