Slashdot Mirror
First Room-Temperature Germanium Laser Completed
eldavojohn writes "MIT researchers have built and demonstrated the first room-temperature germanium laser that can produce light at wavelengths suited for communication. This achievement has two parts: '[U]nlike the materials typically used in lasers, germanium is easy to incorporate into existing processes for manufacturing silicon chips. So the result could prove an important step toward computers that move data — and maybe even perform calculations — using light instead of electricity. But more fundamentally, the researchers have shown that, contrary to prior belief, a class of materials called indirect-band-gap semiconductors can yield practical lasers.' While these are only the initial steps in what may become optical computing devices, the article paints it as very promising. The painful details will be published in the journal Optics Letters."
Let there be light!!!
Now where to get a Germanium Shark?....
*flies to Germany*
Why is this better than existing solid-state lasers?
-jcr
The only title of honor that a tyrant can grant is "Enemy of the State."
But can they be attached to sharks?
Shouldn't Berlin University be the one using the Germanium?
MIT should have made their laser out of Americium.
And it sucks to be Cambridge. There is no such thing as Englandium.
What? No, I don't have anything sensible to say about this story. And anyway, at first I thought it said geranium, and my comment was going to be even stupider than this one.
I am anarch of all I survey.
http://xkcd.com/678/
they invent a geranium laser. Green laser power in your window.
let me know when these can be surgically attached to sharks.
I'm not going to look at my Geraniums in the same way now that they've developed laser technology.
I hope they use it against Bluebottle flies and those wasps that refuse to fly out through the window.
Cool! And I guess all you need to power it is plenty of sunlight, water and the occasional packet of Baby Bio.
Summation 2
Sweet ET can phone home.
And thus, THE 1000 YEAR LASER was born !
I for one welcome our new powered-by-room-temperature-germanium-laser-optical-computer overlords
What is best in life? To crush your enemies, to see them driven before you and to hear the lamentations of their women.
they were talking about photons supplanting electrons in the '80s. and it was supposed to be imminent, right around the corner
AI, tablet computers, rocket cars, fusion power, natural speech computing:
eternally 10 years away
wake me up when it actually happens
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
Reading the article, and the description of how photons are generated, my reaction is... that's it?
They doped germanium to add excess electrons. These electrons, of course, fill the lowest energy states in the valence band (or more accurately, the average electron energy increases, increasing the probability that lower-energy states in the conduction band are filled, if you want to get into density of states and Fermi probability). Then when additional electron-hole pairs are formed, the electrons have to take higher-energy states; the relaxation of electrons in these higher energy states is has enough energy to release a photon.
So, unless the article is a gross oversimplification... they doped an indirect bandgap semiconductor. Something we've been doing for 40 years - silicon is also an indirect bandgap semiconductor. Then, to help things along, they added some stress to the Ge crystal; again, something we've been seeing in silicon for 10-20 years.
What took so long to get this to work?
it would be cool. it would have no resistance. and it would be faster
so no heat sink problems, it would run at much lower power levels, and optical computing would make today's fastest electronic computers look like a texas instruments calculator from the 1970s
additionally, since we're running fibre everywhere today, there's no real interface/ translation between the photon on the line and the photon going into the processor, ideally. the promise is that the internet would become this woven intelligent network, soaring into the stratosphere in terms of speed, interconnectivity, intelligent routing, etc. it would really open up some amazing barely imaginable implications and avenues in terms of what the internet could possibly do. or maybe it would just mean 10^100 spams per picosecond ;-P
assuming of course they tackle the bazillion fabrication issues facing the cheap, easy production of photonic computers. we're a long way away, but i hope to see a rudimentary setup before i kick the bucket
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
In Cambridge they just have to use a dielemental approach which mixes carbon and americium.
Now we need room temperature sharks
Er, but there's a very good reason Germanium is not used much as a semiconductor.
It has very high leakage at room temp, and the leakage goes up exponentially from there.
By the time you get up to 50C it's basically a poor resistor instead of a semiconductor.
So this really is a "room temperature laser", in the sense that you have to cool it to room temperature.
Oh dear. So many replies, so much nonsense. Slashdot these days...
This is a great achievement.
What is great about this laser is that they seem to have found a new
material system that emits at communication wavelength. Communication
wavelength are important because this is a wavelength you can couple well
into optical fibers.
What they seem to do is they apply tensile strain to a germanium layer and
basically push it's energy bands from indirect semiconductor to direct
semiconductor. Direct semiconductors can amplify light, therefore you can
build a laser with them.
Now if you can take this stuff and grow bragg mirrors below and above, you
have something interesting.
Current semiconductor lasers for communication wavelength use nasty
material systems. For fiber optics coupling, you want surface emitting
lasers. Those are right now incredibly hard to manufacture with the
materials we had until now (Think producing two separate wafers and
then joining them mechanically). So we couldn't use them. That may have
changed.
To sum it up: Faster internet.
you know the Germans always make good stuff.
According to Jurgen Michel, principal research associate in the Electronic Materials Research Group and primary investigator on the germanium-laser project,
says Lionel Kimerling, the Thomas Lord Professor of Materials Science and Engineering, who leads the group.
postdoc Jifeng Liu, the lead author on the paper
that or this is the most egotisical team to date.
Curie named Polonium after Poland ("Polonia"). So the whoosh goes to you, coward.
"Victory means exit strategy, and it's important for the President to explain to us what the exit strategy is." G.W.Bush
We also rather own the thermodynamic part of the SI system with the Watt, the Joule, and the Kelvin, not to mention the Faraday and the Newton but that's because the rest of the world was so awed by our scientific progress that they insisted.
For non-native English readers, please insert an irony tag wherever you find most convenient.
From scarped cliff or quarried stone she cries "A thousand types are gone, I care for nothing, no not one."
bedeutet das wir endlich diesen verdammten Haie mit Lasern auf dem Kopf?
Bow-ties are cool.
this is amazing, next to absolute zero one of the most needed temperatures in the lab is exactly room temperature. heck, decades of research were used just to find out what room temperature was of rooms in their native habitat. being able to artificially maintain this temperature by using lasers, so for example a scientists body heat doesn't influence an experiment, is just awesome and will probably go down as one of the greatest advances in science this century.