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Collimating Semiconductor Lasers Without Lenses

Posted by kdawson on 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."

6 of 136 comments (clear)

  1. Umbrella funding by philspear · · Score: 5, Interesting

    The latter could be used for homeland security and environmental monitoring applications.

    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.

  2. Disc size reader? by courteaudotbiz · · Score: 5, Interesting

    I guess this kind of advancement could give birth to disc-sized BluRay or DVD readers, since it is probably, along with the DC motor, the biggest moving part in a DVD assembly... Good for the laptop and ultraportable industry!

  3. Hologram by PPH · · Score: 1, 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 your Nobel prize with the guy selling cheap junk in the booth at the mall.

    --
    Have gnu, will travel.
    1. Re:Hologram by jellomizer · · Score: 2, Interesting

      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.

      --
      If something is so important that you feel the need to post it on the internet... It probably isn't that important.
  4. Steering laser beams by clone53421 · · 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...

    --
    Alexander Peter Kristopeit bought his basement from his mommy for one dollar.
  5. Lightsaber! by salec · · Score: 3, 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.