Optics
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 12, 2010Via Jennifer Ouellette on Twitter, I ran across a Discovery News story touting a recent arxiv preprint claiming to see variation in the fine-structure constant. It's a basically OK story, but garbles a few details, so I thought it would be worth giving it the ResearchBlogging treatment, in the now-traditional Q&A format.
What did they do? The paper looks at some spectral lines in radio emission from a moderately distant galaxy with the poetic name "PKS1413+135." These lines are produced by OH molecules in interstellar gas clouds, and the frequencies they see suggest that there may have…
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 frequency…
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, 2010I'm off to Williamstown this afternoon, to talk about research and alsoHow to Teach Physics to Your Dog. If you need blog-based entertainment, though, here are some shiny new radio buttons for you to click:
You're a beam of light: quick, what's your polarization?online survey
I won't offer a personality analysis based on these results, but after enough people vote, we will be able to determine the angle between this blog's readers and the horizontal. So that's something. Of course, it would require several more polls for full quantum state tomography...
(If you're new here, or ok with old…
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 you…
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…
drorzel | April 20, 2010What's the application? Using lasers to cut and/or cauterize tissue during surgical procedures, instead of the traditional very small very sharp knives.
What problem(s) is it the solution to? 1) "How can we do surgery without touching the tissues being operated on?" 2) "How can I get rid of these annoying glasses/contact lenses?"
How does it work? First, you strap a device to your head that lets you shoot laser beams from your forehead, like one of the X-Men. then you use a magnifying glass to focus it to where it needs to be. Like so:
(I'm not sure exactly what sort of procedure that is,…
drorzel | April 16, 2010Around 470 people voted in yesterday's optics quiz. I continue to be amazed at the power of radio button polls to bring people into the blog.
As of early Friday morning, the correct answer is solidly in he lead-- 63% of respondants have correctly replied that the image remains intact, but is half as bright. You can see this fairly easily by looking at a traditional ray diagram of the image-forming process (re-drawn slightly from yesterday's picture, to get the arrows right):
The arrows in this picture show the paths followed by three different rays of light that all leave from the tip of the…