Lasers
drorzel | June 21, 2010An experiment in Germany has generated a good deal of publicity by dropping their Bose-Einstein Cendensate (BEC) apparatus from a 146 meter tower. This wasn't an act of frustration by an enraged graduate student (anybody who has worked with BEC has probably fantasized about throwing at least part of their apparatus down a deep hole), but a deliberate act of science: They built a BEC apparatus that is entirely contained within a two-meter long capsule inside the evacuated drop tower at the Center of Applied Space Technology and Microgravity (which in German leads to the acronym ZARM, which…
drorzel | June 2, 2010I mentioned in a previous post that one of the cool talks I saw at DAMOP had to do with generation of coherent X-Ray beams using ultra-fast lasers. What's particualrly cool about this work is that it doesn't require gigantic accelerators or nuclear explosions to produce a laser-like beam of x-rays-- it's all done with lasers that fit on a normal-size optical table in an ordinary lab room.
The specific talk I saw was by Margaret Murnane of JILA, who co-leads their ultra-fast laser group, and dealt with a new technique for producing soft-x-rays (~500 eV photons) with ultrafast lasers. We'll do…
drorzel | June 1, 2010While I mostly restricted myself to watching invited talks at DAMOP last week, I did check out a few ten-minute talks, one of which ended up being just about the coolest thing I saw at the meeting. Specifically, the Friday afternoon talk on observing relativity with atomic clocks by Chin-Wen Chou of the Time and Frequency Division at NIST in Boulder.
The real technical advance is in a recent paper in Physical Review Letters (available for free via the Time and Frequency Publications Database, because government research isn't subject to copyright): they have made improvements to their atomic…
drorzel | May 27, 2010Since I sort of implied a series in the previous post, and I have no better ideas, here's a look at Thursday's DAMOP program:
Thursday Morning, 8am (yes, they start having talks at 8am. It's a great trial.)
Session J1 Novel Probes of Ultracold Atom Gases
Chair: David Weiss, Pennsylvania State University Room: Imperial East
Invited Speakers: Cheng Chin, Markus Greiner, Kaden Hazzard, Tin-Lun Ho
Session J2 Coherent Control with Optical Frequency Combs
Chair: Linda Young, Argonne National Laboratory Room: Imperial Center
Invited Speakers: J. Ye, Moshe Shapiro, W. Campbell, …
drorzel | May 26, 2010The conference I'm at this week is the annual meeting of the Division of Atomic, Molecular, and Optical Physics of the American Physical Society (which this year is joint with the Canadian version, the Division of Atomic and Molecular Physics and Photon Interactions, or "DAMPΦ." The Greek letter is a recent addition-- as recently as 2001, they were just DAMP.). As the name suggests, this is a meeting covering a wide range of topics, and in some ways is like two or three meetings running in parallel in the same space.
You can see the different threads very clearly if you look at the different…
drorzel | May 8, 2010While it's not aprt of the official LaserFest package of stuff, Physics World is marking the 50th anniversary of the laser with a couple of really nice pieces on lasers in science and popular culture:
Where next for the laser interviews six laser experts-- Claire Max of UCSC, Bill Phillips of NIST, Steven Block of Stanford, science writer Jeff Hecht, John Madey of Hawaii's FEL lab, and Eric Gustafson of Caltech and LIGO.-- about the current status of lasers in their areas of science, and the future prospects.
From ray-gun to Blu-Ray is a very nice survey of lasers and laser-like devices in…
drorzel | May 3, 2010Voting has closed on the Laser Smackdown poll, with 772 people recording their opinion on the most amazing of the many things that have been done with lasers in the fifty years since the invention of the first working laser (see the Laserfest web site for more on the history and applications of lasers). The candidates in the traditional suspense-building reverse order:
Lunar laser ranging 22 votes
Cat toy/ dog toy/ laser light show 41 votes
Laser guide stars/ adaptive optics 46 votes
Holography 47 votes
Laser eye surgery 53 votes
Optical storage media (CD/DVD/Blu-Ray) 60 votes
Laser…
drorzel | May 2, 2010With over 700 votes cast in the Laser Smackdown poll in honor of the 50th anniversary of the laser, laser cooling has opened a commanding 20-vote lead in the race to be the Most Amazing Laser Application of All Time. If you prefer one of the other options, you have only six hours left to change the final outcome:
Which of the following is the most amazing application of a laser?Market Research
Voting will remain open until midnight, with the ultimate winner announced on Monday, May 3rd. So get reading, and get voting. One vote per computer per user, please-- this is Serious Science.
drorzel | April 30, 2010We're just over 600 votes in the Laser Smackdown poll in honor of the 50th anniversary of the laser, as of early Friday morning. I notice that it has moved off the front page of the blog, though, so here's another signal-boosting repost, just so we have as many votes as possible, to establish maximum scientific validity when we declare the winner the Most Amazing Laser Application of All Time
Which of the following is the most amazing application of a laser?Market Research
Voting will remain open until next Sunday, May 2, just two days from now, with the ultimate winner announced on Monday…
drorzel | April 26, 2010As of 1:45 Monday, 217 people have cast votes in the Laser Smackdown poll. That's not bad, but it's currently being handily beaten by the 271 people who have voted for a favorite system of units.
The nice thing about using actual poll services for this sort of thing, though, is that I can re-post the poll to boost signal a little. So, here it is again, a list of the twelve most amazing laser applications suggested by my wise and worldly readers, with links to short explanations of the pros and cons of each:
Which of the following is the most amazing application of a laser?Market Research…
drorzel | April 23, 2010In 1960, the first working laser was demonstrated, and promptly dubbed "a solution looking for a problem." In the ensuing fifty years, lasers have found lots of problems to solve, but there has been no consensus about which of the many amazing applications of lasers is the most amazing.
Now, in 2010, as we celebrate the anniversary of the laser, we finally have the technology to definitively answer the question: radio-button polls on the Internet!
Which of the following is the most amazing application of a laser?Market Research
Each of the choices above links to a post I wrote here giving…
drorzel | April 22, 2010What's the application? Producing artificial "stars" to serve as a reference for telescopes using adaptive optics to correct for atmospheric turbulence. This allows ground-based telescopes to produce images that are as good as those from the Hubble Space Telescope.
What problem(s) is it the solution to? "How can I make this giant telescope produce even more impressive pictures?"
How does it work?The basic problem with ground-based telescopes, as anyone who has ever looked at the stars or listened to nursery rhymes can tell you, is that stars "twinkle." They appear to fluctuate in brightness…
drorzel | April 21, 2010What's the application? An optical frequency comb is a short-duration pulsed laser whose output can be viewed as a regularly spaced series of different frequencies. If the pulses are short enough, this can span the entire visible spectrum, giving a "comb" of colored lines on a traditional spectrometer. This can be used for a wide variety of applications, from precision time standards to molecular spectroscopy to astronomy.
What problem(s) is it the solution to? 1) "How do I compare this optical frequency standard to a microwave frequency standard?" 2) "How do I calibrate my spectrometer well…
cagapakis | April 20, 2010Light interacts with and controls biological systems in diverse and fascinating ways. Our eyes are made up of thousands of cells that respond to light, sending signals to our brain as light in different colors and shapes moves across them. Photosynthetic cells are full of receptors that can sense and respond to many wavelengths of light, allowing cells to absorb light for photosynthesis, but also to move towards areas of more sunlight and know when the seasons are changing. Synthetic biology takes these light-responsive systems as parts that can be recombined, shuffled and integrated into…
drorzel | April 19, 2010What's the application? The goal of laser ignition fusion experiments is to heat and compress a target to the point where the nuclei of the atoms making up the sample fuse together to form a new, heavier nucleus, releasing energy in the process. Nuclear fusion is, of course, what powers stars, and creating fusion in the laboratory has been the holy grail (well, a holy grail, at any rate) of nuclear physics research for the last sixty-plus years.
What problem(s) is it the solution to? 1) "Can we create fusion reactions in a laboratory setting on Earth?" 2) "How can we get more helium without…
drorzel | April 16, 2010What's the application? Holograms are images of objects that appear three-dimensional-- if you move your head as you look at a hologram, you will see the usual parallax effects, unlike a normal photograph, which is fixed. So, if your hologram includes one object that is partly behind another object, you can see around the obstruction by moving a bit to the side, just as you would if the original objects were in front of you.
What problem(s) is it the solution to? 1) "How can we jazz up flat images and make them look more lifelike?" 2) "How can we make credit cards harder to copy?"
How does it…
drorzel | April 14, 2010What's the application? Telecommunications, namely, the sending of messages over very long distances by encoding them in light pulses which are sent over optical fibers.
What problem(s) is it the solution to? "How can we send large numbers of messages from one place to another more efficiently than with electrical pulses sent down copper wires?"
How does it work? The concept is dead simple: You take a signal and encode it in light-- this could be analog, like the SpectraSound demo LaserFest is selling, with higher intensity meaning higher signal, or it could be digital, with a bright pulse…
drorzel | April 12, 2010What's the application? LIGO stands for Laser Interferometer Graviitational Wave Observatory, because (astro)physicists feel free to drop inconvenient words when making up cute acronyms. This is an experiment to look for disturbances in space-time caused by massive objects, which would manifest as a slight stretching and compression of space itself.
What problem(s) is it the solution to? 1) "Can we directly observe the gravitational waves that are predicted by the equations of General Relativity?" 2) "Can we detect things like colliding black holes, because that would be awesome!"
How does it…
drorzel | April 12, 2010Several weeks ago, I announced a contest to determine the Most Amazing Laser Application. Personal issues interrupted this, but I want to finish it out in honor of LaserFest Here's the list of finalists, with links to those already written up:
Cat toy/ dog toy/ laser light show
Laser cooling/ BEC
Lunar laser ranging
Optical tweezers
Optical storage media (CD/DVD/Blu-Ray)
LIGO
Telecommunications
Holography
Laser ignited fusion
Laser eye surgery
Laser frequency comb/ spectroscopy
Laser guide stars/ adaptive optics
I'll be writing up LIGO shortly, and will try to finish the whole thing as soon…
drorzel | April 9, 2010The National Science Board made a deeply regrettable decision to omit questions on evolution and the Big Bang from the Science and Engineering Indicators report for 2010. As you might expect, this has stirred up some controversy.
I wasn't surprised to learn this, as I had already noticed the omission a couple of months ago, when I updated the slides for my talk on public communication of science-- the figure showing survey data in the current talk doesn't include those questions, while the original version has them in there. I noticed it, and thought it was a little odd, but it had no effect…