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Collimating Semiconductor Lasers Without Lenses
Posted by
kdawson
on Tue Jul 29, 2008 12:07 PM
from the should-make-somebody-rich dept.
from the should-make-somebody-rich dept.
An anonymous reader writes "Researchers at Harvard University and Hamamatsu Photonics have found a way to collimate lasers without lenses. In the new 'plasmonic collimator' technique, grooves are etched directly into the semiconductor laser's internal mirror. This results in surface plasmons giving rise to constructive interference, eliminating the need for the bulky optical lenses that usually focus the light from semiconductor lasers. The technique has promise for steering laser beams without moving parts and for working with polarized light."
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Submission: Lasers need lenses no more by Anonymous Coward
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what... (Score:2, Funny)
no sharks?
Re: (Score:3, Funny)
That joke has jumped the shark.
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I think you mean it has nuked the fridge
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...the shark jumps you!
Sweeeet! Shark sex!
Re: (Score:3, Informative)
Wikipedia says [wikipedia.org]... er, actually no, it doesn't. The only mention I could find of the word "Sex" in its article about sharks is an occurance of ASEXUAL reproduction (i.e., virgin birth).
It only mentioned the "Jesus Shark". Fish generally don't copulate like mammals, but instead the female lays eggs and the male then ejaculates on the eggs. I'm not sure if sharks reproduce like this, but if so, well, if the shark jumps you you will get laid -- TO REST.
I think the goatse site has an article about bestiality wit
It may be very cool (Score:4, Funny)
But can you hammer a 6 inch spike through a board with your penis?
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I don't plan to try without it.
Re:It may be very cool (Score:5, Insightful)
Amazing. A reference to a relatively mindless comedy (Austin Powers) gets modded up, while a reference to a really good geek movie (Real Genius [imdb.com]) gets modded down as off topic. *sigh* Kids with mod points, I tell ya.... Bets on whether the person who modded the parent down had been born yet when this movie came out? :-)
Parent
Re: (Score:3, Informative)
Welcome to today's Slashdot. Mindless fools that are 15 years old. The 80's? Don't even remember 'em!
Or maybe it was always that way and we older folks just don't have the time to invest in shaping this community anymore and thus it has become a haven for the newcomers. Oh, and get off my lawn! :-P
"Put simply, in deference to you Kent, it's like lasing a stick of dynamite." --Chris Knight
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Hmm... in hindsight a better quote might have been:
"I think the young people enjoy it when I "get down" verbally, don't you?" --Dr. Meredith
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Welcome to today's Slashdot. Mindless fools that are 15 years old. The 80's? Don't even remember 'em!
Sheeze, relax. We're getting of your lawn already.
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Come on, offtopic? Real Genius anyone???? Totally on-topic and funny to boot.
Umbrella funding (Score:5, Interesting)
I don't know much of anything about physics research. Here in biology, if any aspect of your research has applications to cancer, you talk that connection up, even if it's somewhat tenous. There's a glut of funding available for cancer wheras there's substantially less for equally important medical research on aspects of biology "lay people" don't understand. A lot of research funded with cancer research money really has very little chance of actually taking steps towards curing cancer (which is not to say we shouldn't be funding those projects.)
Is "homeland security" the equivalent of that for physics research? Show a link as to how your project might be used to prevent terrorism and you'll get a blank check from the government? I sincerely hope so, at least some good can come out of our paranoia.
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Physics has a lengthy history of being funded by military operations. For example, the laser itself stems from research into radar guided bombing systems for the military.
http://www.bell-labs.com/history/laser/ [bell-labs.com]
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Short answer: yes. Longer answer... oh wait, some guys with a black van are at the door, I'll be back in a minute.
Homeland security? (Score:2, Insightful)
The researchers claimed that if they can achieve a fully collimated laser, it will lower the cost of communications lasers by eliminating the need for lenses while enabling long-range chemical sensing. The latter could be used for homeland security and environmental monitoring applications.
I don't remember laser sensors being a pressing need for defense of the motherland. Am I downplaying the risks here? I can only imagine that cheaper components will make total surveillance even easier.
Disc size reader? (Score:5, Interesting)
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No. DVD and BluRay can have more than one layer. Without servo focusing it would be impossible to select a layer to read.
The article called. Wishes you would read it. (Score:2, Insightful)
Exactly which part of “steering laser beams without moving parts” escaped your understanding?
Re:Disc size reader? (Score:5, Insightful)
From the article:The researchers claimed that the plasmonic collimator effect is similar to the way phased-array antennas steer a beam, creating the possibility of steering laser beams with no moving parts.
Parent
Re:Disc size reader? (Score:5, Informative)
Parent
Back In My Day (Score:4, Funny)
We didn't have solid state lasers, you had to bring your own tank of CO2 and a Xenon flash lamp to get the thing pumping. You had to adjust your mirrors with a micrometer. muttering to myself... "damn smartass kids" as I wander across the room to get my Geritol.
Re:Back In My Day (Score:4, Funny)
Parent
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Amateur. We would use a milk bottle and Chuck Norris would scare the CO2 into the bottle from the air. Get off my lawn while you're getting that Geritol.
Hologram (Score:2, Interesting)
Is this basically the same effect used by those cheap laser pointers to project cute pictures instead of a simple dot? For $10 I bought such a pointer that included about a dozen interchangeable tips. Each contains a tiny plastic film (a hologram) that shapes the beam into a cute symbol (arrow, smiley face, etc.).
It sounds like what is being proposed is a hologram (basically a kind of diffraction grating) etched directly onto the die surface. Not a bad idea, but not really new. Unless you want to share you
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But that is with a lens. What they are doing is with plasma. So it can be controlled without moving parts. In theory with that you have a program that follows your eyes. then using these lasers they can shine the image and hit the right cells for realistic holodeck like images.
Re:Hologram (Score:5, Funny)
Dear PPH,
I am a scientist on the team mentioned in the article and I just wanted to say that you, sir, have rocked my world! I just went down to the mall after reading your comment, and bought one of these "laser pointing" devices. And holy shit, you were totally right! There is absolutley nothing unique or different with the research I've spent 7 years of my life on. This cheap $10 plastic toy is exactly the same thing as an laser built into an IC without a lense or moving parts. EXACTLY the same. I mean, they're both totally like lasers right? Mind. Fucking. Blown. Anyways, the guy that sold me the device is keeping quiet in exchange for top billing on the article in Science, and a piece of the sweet sweet Nobel prize money.
Anyways, next up for me is taking the $10 plastic toy (because, after all, my research is completely useless as you've pointed out) and integrating it into a quantum computer. Refocusing the laser at quantum scales at the speed required to run a quantum computer can easily be achieved by swapping plastic tips on the end of the pointer (a process we've dubbed "rejiggering the doohickey" in science speak).
Thanks, and God Bless for pointing out the errors of my way. Guess I need to spend less time in the lab and more time in the mall!
Sincerely yours,
Prof. T. Barnum Humperdink III
Parent
Re:Hologram (Score:4, Funny)
You sir, owe me a new keyboard!
Posts like that should come with a "Do not read this while drinking" warning.
Parent
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In some sense, yes, it is related to those holograms. They are indeed patterning the facet surface to project a desired pattern.
One difference is that they are using "plasmonics" instead of holography/diffraction. This means they are using metals (materials that conduct electricity) instead of dielectrics (materials that don't). Plasmonics is more challenging, but offers the potential to create smaller (subwavelength) devices.
Whether or not they are using diffraction or plasmonics, this is useful because
Translation: (Score:3, Informative)
"Researchers at Harvard University and Hamamatsu Photonics have found a way to collimate lasers without lenses. In the new 'plasmonic collimator' technique, grooves are etched directly into the semiconductor laser's internal mirror. This results in surface plasmons giving rise to constructive interference, eliminating the need for the bulky optical lenses that usually focus the light from semiconductor lasers. The technique has promise for steering laser beams without moving parts and for working with polarized light."
Translation for people like me: Smart dudes at the #1 school and a lab with lots of funding and laserbeams found a way to fire said laserbeams by shaping the mirror instead of having a flat mirror and firing it through a shaping lense. This is good 'cuz now they will be able to do stuff they had a hard time doing before.
Re:Translation: (Score:5, Insightful)
1. Someone dumbing down a tech article for the slashdot crowd to read.
2. Said post getting modded up as informative.
Welcome to the new slashdot. Striving to be more like FOX news every day.
Parent
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I don't think that's correct. You know the flat fresnel lenses [wikipedia.org] they put on rear windows of minivans, and make into credit card sized magnifying glasses you can stick in your wallet? This is about not only using the same technique as a fresnel lens instead of a conventional lens, but what's more doing away with the lens entirely by putting the grooves directly on the laser's rod.
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Translation for people like me: Smart dudes at the #1 school and a lab with lots of funding and laserbeams found a way to fire said laserbeams by shaping the mirror instead of having a flat mirror and firing it through a shaping lense. This is good 'cuz now they will be able to do stuff they had a hard time doing before.
That's a pretty accurate description. I'd just point out that it isn't so much shaping the mirror as it is patterning the mirror. The mirror is still flat, it just has parts of it etched away.
Steering laser beams (Score:5, Interesting)
I'm a little curious... TFA didn't really clear this up much. It sounds like they've managed to focus the laser without needing a lens, which is definitely geeky enough to warrant notice... good stuffs like "interfere constructively" and "plasmonic collimator effect" are always fun.
I am a little bit perplexed, though. They're apparently using etched grooves to induce electromagnetic interference which results in better polarization/linearity of the emitted light. What I don't understand is how this could be used to electronically "steer" the beam. It sounds to me like it can only be used to point the beam in one static direction. The article mentioned a "spatial emission pattern", but I'm really not sure what that means in English...
They seem to be excited over the fact that no moving parts are involved, which also puzzles me. The lens in a stationary laser isn't a moving part, and it sounds like they've found a technology that replaces the lens. A laser that could be aimed, though, required moving lenses/mirrors... returning to my original question, I'm curious how they're going to "steer" the laser without moving parts.
Finally, I'm really not sure what they mean by this statement:
The researchers plan to etch concentric circular grooves in an attempt to fully collimate the laser beam in all directions.
Isn't that kind of contradictory? Like saying "we intend to fully polarize the light in all directions"? You can't have partially polarized light, and you can't have partially collimated rays... that's like saying you have somewhat parallel lines or a slightly rectangular square...
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The article is misleading. They etched a single pattern in the facet, so the beam is always steered in one direction. With multiple lasers and facets the could choose different directions, I guess.
Re:Steering laser beams (Score:5, Informative)
If you know the wavelength of a beam of light, you can use interference effects to direct it. This group's current laser uses parallel etched lines to collimate the beam in the Y direction. By switching to concentric circles, they can collimate the beam in both X and Y directions.
You CAN have partially polarized light, though. Daylight is partially polarized. If you hold up a linear polarizer to the sky, it will be slightly darker or lighter depending on how you orientate it.
You can have partially collimated light, too. In fact, you can never have completely collimated light. Light tends to spread out the farther it travels. This is usually attributed to diffraction, but in reality they are both results of the true behavior of light - which is modeled by quantum electrodynamics.
Parent
Sounds Fishy to Me (Score:4, Funny)
I didn't RTF because... "plasmons"?
Sounds fishy to me. Sounds like something a Jedi Knight uses.
Surface Plasmons (Score:2)
I believe "Surface Plasmons" were either a rock band or the bad guys from a Dr Who episode.
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I didn't RTF because... "plasmons"? Sounds fishy to me. Sounds like something a Jedi Knight uses.
Wikipedia says [wikipedia.org] "In physics, a plasmon is a quantum of a plasma oscillation. The plasmon is the quasiparticle resulting from the quantization of plasma oscillations just as photons and phonons are quantizations of light and sound waves, respectively. Thus, plasmons are collective oscillations of the free electron gas density, often at optical frequencies. They can also couple with a photon to create a third quasi
Lightsaber! (Score:4, Interesting)
Ever since I watched Star Wars for the first time, I had this idea: if I could rapidly move common focal point of thousands of tiny laser beams along the fixed segment of handle axis, with constructive interference (mostly) sustained, with lasers' wavelength matched to a line of absorptive spectrum of atmospheric gas (on Earth it would be nitrogen), I would have a plasma weapon (or tool) very much resembling a lightsaber.
It should also have adaptive (microcomputer controlled) focusing, so that if any obstacle enters the "blade" segment, all the lasers immediately keep focus on the point of contact, to make it yield to blade as fast as possible
Now, there is a way to it. I imagined some piezoelectric-actuated mirrors would do, but had no idea how to construct it. This new thingy is so much better and more fine-grained.
Roger Crossbow, the rabbit is in the hole... (Score:3, Funny)
Now all we need is a large spinning mirror...
Wow, that summary.... (Score:2)
http://www.youtube.com/watch?v=PtuqjFf7-N4
That's what they used... (Score:2)
Surface plasmons... that's what Dillan and Troy used to generate a feedback loop in the Cylons in that episode of Battlestar Galactica 1980.
A more simple solution (Score:2)
You can achieve the same effect by inverting a lateral undefined cloud. If we use the inertial containment nacelle to align it with the primary undefined coil, then by modifying this cargo flux bay, we can make it work in conjunction with the acute plasma procedure. I believe that this will increase the efficiency of the primary deflector undefined by 16 percent. Thus reducing the load on the optical isolinear plate.
Hey, makes about as much sense as the article's existing intro blurb.
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Translation: instead of a conventional curved lens, they use a fresnel lens. This allows them to carve the lens directly into the laser, make it flat, and possibly tune it.
You're at slashdot, where occasionally you're going to run into some articles that are writen at a postgraduate level instead of the eighth grade level sanity would logically insist on.
I once read a paper that used the word "enumerate" five times in a single paragraph, and didn't once use the word "count". The submitter could have communi
I had to look up collimate (Score:2, Funny)
A dog's wife.
So this about frikkin' dogs with frikkin' wives with frikkin' laser beams attached to their heads?
So much for lenses (Score:2)
That, plus the possible development of various "bug eye" type non-lensed photography [stanford.edu] methods could be bad news for the long-term viability of lens manufacturers. It may be sort of like Kodak in the early 90's- the vast majority of their profits came from film, and it was obvious film was rapidly heading towards obsolescence. The verdict's certainly not in yet on lenses the way it was on film. But what do you do, if you're a giant, successful corporation, but