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Collimating Semiconductor Lasers Without Lenses
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."
"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.
No. DVD and BluRay can have more than one layer. Without servo focusing it would be impossible to select a layer to read.
Sounds a lot like a phased array radar: http://en.wikipedia.org/wiki/Phased_array. You can steer beams from those without moving parts, too.
If you can polarize the light, you can have multiple layers distinguished by polarity. Besides, I thought multi-layer systems usually used different frequencies, as optical media work by seeing what reflects and what doesn't. If you add the ability to polarize the light, you can double the number of layers.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
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
Javascript + Nintendo DSi = DSiCade
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.
Wikipedia says... 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 with a dolphin. But no sharks.
Or lasers.
mcgrew's razor: Never attribute to stupidity that which can be explained by greedy self-interest