Tuesday, December 12, 2006

Good News and Bad News

The good news is, yesterday we got the biggest, brightest trap we've ever seen. It took up half the camera's view. Its brightness saturated both cameras and drowned out all other light in the chamber in the pictures. It looked like the sun. It looked like it was going to eat the lab. Our advisor asked us why it was so much bigger, and Ken said "Because we rock?"

Here's the thing -- it was so bright, you could even see it with your naked eye. The reason that is surprising is because it glows in infrared.

"Wait, how can you see infrared with the naked eye?" you ask. Well, the eye's response doesn't cut off sharply at a certain wavelength. It just gets less and less sensitive as you go to longer and longer wavelength. Our light is far enough past the peak sensetivity of the red-receptors in your eye to qualify for the term "infrared," but the eye still has some sensetivity to it. In other words, if it's really bright, you can still see it.

The trap was that bright.

Somehow seeing something like that with your naked eye is much more impressive than merely seeing it on a screen or through a viewer. You know it's not a special effect. It's like -- wow, there's a ghostly glowing red dot just hovering in the center of our vacuum chamber. Okay, I believe in quantum mechanics now.

Nothing else could possibly explain that.

The bad news is, we got this incredible trap by going back to the old set up. See, the way we usually get a trap involves having laser beams that go through the trap (it's partly transparent), hit a mirror, and then go through it again from the other direction. What we need to do now, for reasons I won't get into, is have one beam going through it from one direction, and a separate (but identical) beam going through it from the other direction.

When we reflect one beam back on itself, the trap works, and works spectacularly. When we take off the reflectors and send a supposedly identical beam in from that direction, it doesn't work at all. How can that be?

So that's where we are now, the frustrating mystery we are still trying to solve. But seeing the largest trap ever, and seeing it with our naked eye, makes up for the frustration a little.

For reference this post has a picture of what the trap normally looks like on our TV screen. Yesterday, it took up, literally, about a third of that screen. So, huge. I'll bring a camera in today... And here is a picture of what a trap looks like when you look at it with your naked eye. The difference is, theirs is a sodium trap, and sodium glows with visible yellow light, which makes it much easier to see than our infrared glow. But other than appearing redder and dimmer, that's just what ours looked like.


Jenn said...

Woohoo! A fellow "trapper". Well, I deal with ion traps and not MOTs but still... I understand the awesomeness that is holding a bunch of atoms in a small area and making them bend to your will (insert *Mwahahaha* here ;)

We aren't lucky enough to get to see ours though. That sounds pretty spectacular.

Simon W said...


Mary said...

Jenn -- Actually, I know you're a fellow trapper. You see, I've been reading your blog for a little while, just haven't left a comment. The internet is weird, eh?

Simon -- Five exclamation marks?

Anyway, it's a little premature. When we actually get it working successfully in the new configuration (and then successfully launch the atoms upward... that's what the new configuration is for. And then succesfully hold them in a different type of trap above the original trap... Which happens to be inside a resonating optical cavity we hope to have successfully built by then... Well, you know, when we successfully graduate, that'll be the time for five exclamation marks.