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First Room-Temperature Germanium Laser Completed

timothy posted more than 4 years ago | from the please-keep-your-comments-germanium dept.

Communications 80

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."

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And then... (0)

Anonymous Coward | more than 4 years ago | (#31032830)

Let there be light!!!

Germanium Laser? (0)

Anonymous Coward | more than 4 years ago | (#31032832)

Now where to get a Germanium Shark?....

*flies to Germany*

Re:Germanium Laser? (1, Funny)

Anonymous Coward | more than 4 years ago | (#31032918)

blah blah sharks etc etc dead horse etc blah

Re:Germanium Laser? (1)

hey! (33014) | more than 4 years ago | (#31033358)

You miss the point.

At last, we can lase about in a comfortable, shirtsleeves environment.

Re:Germanium Laser? (1)

MRe_nl (306212) | more than 4 years ago | (#31033852)

Think of the potential band-width of full spectrum fibre-optics.
In a comfortable, shirtsleeves environment of course.

Re:Germanium Laser? (1)

hey! (33014) | more than 4 years ago | (#31033972)

This thread is starting to sound like an infomercial.

Throw away that bulky refrigeration equipment!

Say goodbye to those messy liquid nitrogen dewars!

No more trekking down to crowded laboratories!

You can enjoy wide-bandwidth germanium laser technology in the privacy of your own home!

(Cut to testimonial): I really enjoy having my own home germanium laser set-up. I used to schlep down to the lab five times a week, and as often as not all the equipment was in use. Now I keep my room temperature germanium laser next to the couch and use it while I'm watching TV. After just three weeks I had more definition than I'd ever had before.

Re:Germanium Laser? (1)

MRe_nl (306212) | more than 4 years ago | (#31034228)

Now, at last, I too can download 15 bibles per second, in the privacy of my own home?
Praise the Lord!

Fill us in, please? (2, Insightful)

jcr (53032) | more than 4 years ago | (#31032836)

Why is this better than existing solid-state lasers?

-jcr

Re:Fill us in, please? (4, Informative)

Anonymous Coward | more than 4 years ago | (#31032872)

Why is this better than existing solid-state lasers?

-jcr

Already being integrated with silicon for circuits [wikipedia.org] . And like the summary says, manufacturing is much easier.

Re:Fill us in, please? (1)

aurispector (530273) | more than 4 years ago | (#31033502)

Manufacturing is easier, provided you first have a stable supply of the element. In the future, rare earth elements will dominate the high tech economy. China is the world's largest producer.

Basically, instead of the middle east having us by the short hairs, in the future it's going to be the Chinese.

Re:Fill us in, please? (1)

dakameleon (1126377) | more than 4 years ago | (#31034060)

instead of the middle east having us by the short hairs, in the future it's going to be the Chinese.

In the future?

Re:Fill us in, please? (4, Funny)

Shadow of Eternity (795165) | more than 4 years ago | (#31033052)

Stronger, faster, more efficient.

Downside is it has a tendency to encroach on polandium lasers...

Re:Fill us in, please? (1)

someone1234 (830754) | more than 4 years ago | (#31033318)

You meant polonium, right?

Re:Fill us in, please? (0)

Anonymous Coward | more than 4 years ago | (#31033486)

Whoosh!

Who's Whooshing Who? (1)

ciroknight (601098) | more than 4 years ago | (#31035410)

Curie named Polonium after Poland ("Polonia"). So the whoosh goes to you, coward.

Re:Fill us in, please? (1)

truthsearch (249536) | more than 4 years ago | (#31034084)

No, he meant bolognium, whose atomic weight is deliciously snacktacular.

Re:Fill us in, please? (1)

rossdee (243626) | more than 4 years ago | (#31034120)

and also Francium (element #87)

Re:Fill us in, please? (3, Funny)

Shadow of Eternity (795165) | more than 4 years ago | (#31034302)

Only the Vichi isotope is conducive to interactions with germanium, the rest react violently.

Re:Fill us in, please? (1)

Hillgiant (916436) | more than 4 years ago | (#31036908)

And I thought it was only suitable for popping giant balls of popcorn.

Re:Fill us in, please? (1)

steelfood (895457) | more than 4 years ago | (#31036944)

Stronger, faster, more efficient.

On the other hand, it has no wireless and not as much space as a Nomad.

Re:Fill us in, please? (1)

Pictish Prince (988570) | more than 4 years ago | (#31040586)

Stronger, faster, more efficient.

Downside is it has a tendency to encroach on polandium lasers...

Wow, Godwin's Law didn't waste any time kicking in here.

Re:Fill us in, please? (0)

Anonymous Coward | more than 4 years ago | (#31033102)

Is it too much to ask to read the summary?

Re:Fill us in, please? (1)

AlamedaStone (114462) | more than 4 years ago | (#31036244)

Is it too much to ask to read the summary?

I'm on a schedule here. I don't have time to read the summary AND post comments! So which sort is this thing, another Australian contraction of freedoms or a NYCL recap of RIAA legal manouvers?

Re:Fill us in, please? (4, Informative)

jank1887 (815982) | more than 4 years ago | (#31033446)

lasers compatible with silicon processing technology are a good thing. SiGe is a proven IC material set with a sort-of robust processing knowledgebase. Incorporating Germanium optics into silicon designs supposedly will usher in a new era of wacky computing with on-chip optical logic elements, interconnects, etc. Some people think quantum computing would be easier if you were working in the optical instead of electrical domain. Blah blah. People made silicon lase not too long ago, but efficiency was horrible. Germanium can make for a much better optics, and now you can put in together.

Re:Fill us in, please? (2, Informative)

soundguy (415780) | more than 4 years ago | (#31033508)

Silicon has a 0.7v drop across a pn junction, whereas germanium only drops 0.3v. I would imagine that being able to use much lower operating voltage has some benefits.

Re:Fill us in, please? (0)

Anonymous Coward | more than 4 years ago | (#31033872)

Really, the drop across a junction can be controlled by doping, and the profile of the p-n interface. Silicon could reach as low as around 0.5V, realistically.

Ge may have intrinsically lower Vbi, but Ge as a substrate is inherently less stable that Si with respect to temperature fluctuations.

Re:Fill us in, please? (0)

Anonymous Coward | more than 4 years ago | (#31034380)

Why is this better than existing solid-state lasers?

-jcr

Until now, solid-state lasers could not be built onto a monolithic Silicon IC, but Germanium is used in combination with Si all the time (notably for straining the Si and heterojunctions). So we understand very well how to get Si and Ge to form into a monolithic crystal. This is not "better" than current solid-state lasers optically but because this can be integrated into Si for the advancement of Si Photonics, and therefore the direct integration of modern digital circuits with photonics. Until now, Si Photonics required an external light source.

Additionally, this is of scientific significance because in-direct bandgap materials (e.g. Si, Ge) generally are not optically friendly materials.

JR

Re:Fill us in, please? (0)

Anonymous Coward | more than 4 years ago | (#31034534)

Your average LED uses Gallium Arsenide a type III-V semiconductor and 99.999% of circuits use Silicon a type IV semiconductor.

Mixing these two is a huge undertaking.

Germanium is also a type IV semiconductor and SiGe has been made for years.

Re:Fill us in, please? (0)

Anonymous Coward | more than 4 years ago | (#31035354)

right now the only real roadblock to having fully integrated optical links within silicon chips is a good light source.

Re:Fill us in, please? (1)

davester666 (731373) | more than 4 years ago | (#31036894)

Sharks aren't allergic to germanium, so it's safer and cheaper to mount this laser on their heads, because you don't need so much shielding. This reduced shielding also makes it easier for the shark to aim the laser, easier to swim [less drag], and more environmentally friendly.

Ah Yes... (2, Funny)

PiAndWhippedCream (1566727) | more than 4 years ago | (#31032868)

But can they be attached to sharks?

Re:Ah Yes... (0)

Anonymous Coward | more than 4 years ago | (#31032898)

Ofcourse all lasers are compatible with sharks. Thats in the definition of laser.

Re:Ah Yes... (1)

GaryOlson (737642) | more than 4 years ago | (#31034106)

Vacuum deposited silicon substrates anchored to the shark tend to itch; and the shark scratches that location constantly. So you need to solve the skin irritation problem before you lay down the germanium layer.

Make mine from Ruritanium (5, Funny)

ignavus (213578) | more than 4 years ago | (#31032886)

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.

Re:Make mine from Ruritanium (5, Funny)

dcmoebius (1527443) | more than 4 years ago | (#31033002)

And it sucks to be Cambridge. There is no such thing as Englandium.

England could use noble gases, perhaps?

Re:Make mine from Ruritanium (0, Troll)

darthdavid (835069) | more than 4 years ago | (#31033404)

English cooking not agree? Though I'd hardly call it noble...

Re:Make mine from Ruritanium (0)

Anonymous Coward | more than 4 years ago | (#31064208)

I do not find the joke funny != Troll retard mod

Re:Make mine from Ruritanium (1)

steelfood (895457) | more than 4 years ago | (#31038014)

I would not want to be in that lab when the laser fires.

Re:Make mine from Ruritanium (1)

outsider007 (115534) | more than 4 years ago | (#31033014)

Yeah, I was going to go with something about space nazis but then I thought, oh whatever.

Re:Make mine from Ruritanium (1)

Shadow of Eternity (795165) | more than 4 years ago | (#31033054)

You could always say that a germanium laser is great because it doesn't require electricity, it runs without any juice...

Re:Make mine from Ruritanium (0)

Anonymous Coward | more than 4 years ago | (#31033320)

All my geraniums are happy at room temperature.

Re:Make mine from Ruritanium (4, Insightful)

MightyDrunken (1171335) | more than 4 years ago | (#31033340)

It does suck for the English, they could use Europium but the best I could find was Rhodium, meaning rose. The next best is Rutherfordium for Ernest Rutherford as he was a British citizen but was born a New Zealander.
Hell even Ytterby a Swedish village has two elements named after it (Ytterbium and Yttrium).

A few more but by no means an exhaustive list.

  • Paris (Lutetium)
  • German state of Hesse (Hassium)
  • Gaul-France (Gallium)
  • France (Francium)
  • Germany (Germanium)
  • Kobold Goblin (Cobalt)
  • California (Californium)
  • University of California, Berkeley (Berkelium)
  • Scandinavia (Scandium)
  • Nobel Institute in Sweden (Nobelium)

Re:Make mine from Ruritanium (1, Insightful)

Anonymous Coward | more than 4 years ago | (#31033408)

Actually, Ytterby has four elements named after it: Ytterbium, Yttrium, Terbium and Erbium.

Re:Make mine from Ruritanium (1)

subbydubbydoo (1675036) | more than 4 years ago | (#31034600)

i'd prefer plumbum, i think it's latin for lazy arse, swinging the lead or something...

That's because we're not nationalistic (1)

Kupfernigk (1190345) | more than 4 years ago | (#31035532)

We are not nationalistic (because we don't need to be.) No country name on our stamps because we invented them. Davy discovered sodium and potassium (natrium and kalium) and gave them proper Latin names. Rutherford was a colonial so it was OK to name an element after him. In fact Herschel (who was partly German, which explains it) wanted to call his newly discovered planet "Siderius Georgius" after King George, but the King said "Herschel, we British don't do that kind of thing. Kindly stick it up your anus", and the name stuck.

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.

Re:Make mine from Ruritanium (2, Insightful)

pizza_milkshake (580452) | more than 4 years ago | (#31035890)

Don't forget Terbium (Tb) and Erbium (Er). http://en.wikipedia.org/wiki/Ytterby [wikipedia.org]

Re:Make mine from Ruritanium (1)

Goaway (82658) | more than 4 years ago | (#31036608)

Also Yttrium and Ytterbium.

Re:Make mine from Ruritanium (0)

Anonymous Coward | more than 4 years ago | (#31042208)

Also Terbium and Erbium.

Re:Make mine from Ruritanium (1)

thexray (1000044) | more than 4 years ago | (#31047496)

Don't forget Yttrium (Y) and Ytterbium (Yb).

Re:Make mine from Ruritanium (1)

hey! (33014) | more than 4 years ago | (#31033348)

And it sucks to be Cambridge. There is no such thing as Englandium.

I know. And the atomic symbol "Uk" is available too.

CAm (1)

pjt33 (739471) | more than 4 years ago | (#31033662)

In Cambridge they just have to use a dielemental approach which mixes carbon and americium.

Re:Make mine from Ruritanium (1)

vegiVamp (518171) | more than 4 years ago | (#31033692)

> And it sucks to be Cambridge. There is no such thing as Englandium.

They can use Britannium.

"While these are only the initial steps [...]" (0)

Anonymous Coward | more than 4 years ago | (#31032938)

http://xkcd.com/678/

I'll be impressed when (1)

lxs (131946) | more than 4 years ago | (#31032978)

they invent a geranium laser. Green laser power in your window.

Re:I'll be impressed when (1)

hey! (33014) | more than 4 years ago | (#31033378)

I'll be impressed because they'll need coherent geraniums. (er... geranii?)

Re:I'll be impressed when (1)

Sique (173459) | more than 4 years ago | (#31034294)

gerania.

Yawn (0, Redundant)

dcmoebius (1527443) | more than 4 years ago | (#31032992)

let me know when these can be surgically attached to sharks.

Laser equipped Geraniums? (0)

Anonymous Coward | more than 4 years ago | (#31033000)

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.

Geranium Laser? (1)

Rik Sweeney (471717) | more than 4 years ago | (#31033016)

Cool! And I guess all you need to power it is plenty of sunlight, water and the occasional packet of Baby Bio.

Re:Geranium Laser? (1)

chromas (1085949) | more than 4 years ago | (#31033044)

and the occasional packet of Baby Bio

A diaper?

ET (1)

t0qer (230538) | more than 4 years ago | (#31033026)

Sweet ET can phone home.

speaking of nazis... (0)

Anonymous Coward | more than 4 years ago | (#31033180)

And thus, THE 1000 YEAR LASER was born !

In this case, (1)

brunokummel (664267) | more than 4 years ago | (#31033302)

I for one welcome our new powered-by-room-temperature-germanium-laser-optical-computer overlords

ah yes, photonic computing (2, Interesting)

circletimessquare (444983) | more than 4 years ago | (#31033394)

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

Re:ah yes, photonic computing (0)

Anonymous Coward | more than 4 years ago | (#31033538)

Is there any evidence that this still-to-exist optic computing will be better than our current electronic computing?

yes, it would be (3, Interesting)

circletimessquare (444983) | more than 4 years ago | (#31033620)

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

Re:yes, it would be (0)

Anonymous Coward | more than 4 years ago | (#31033708)

I can promptly agree with the low power/heat argument, but would it really be faster?

Since they haven't yet created a photonic transistor, we cannot know how fast it would be able to switch from saturation to cut-off.

With our current technology, the switching speed is limited by the amount of heat created in the process, but we cannot state the same if the optic technology doesn't exist yet.

Re:yes, it would be (1)

Dekker3D (989692) | more than 4 years ago | (#31033850)

uhm.. no photonic transistors yet?
from wikipedia: "A completely optical computer requires that one light beam can turn another on and off. This was first achieved with the photonic transistor, invented in 1989 at the Rocky Mountain Research Center"

of course, it could be some vandalism or something..

Re:yes, it would be (0)

Anonymous Coward | more than 4 years ago | (#31035628)

Would it be faster? You can send information at about 80% of c using proper cables, but fiberoptics are limited to around 2/3 of c (because of the diffraction of glass). Perhaps faster in terms of bandwidth, but in terms of latency?

Re:ah yes, photonic computing (1)

vegiVamp (518171) | more than 4 years ago | (#31033834)

Yes, Sleeping Beauty.

Re:ah yes, photonic computing (1)

steelfood (895457) | more than 4 years ago | (#31038116)

AI, tablet computers, rocket cars, fusion power, natural speech computing

One of these does not belong with the others.

That's it? (0)

Anonymous Coward | more than 4 years ago | (#31033540)

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?

Now we need room temperature sharks (1)

Joe The Dragon (967727) | more than 4 years ago | (#31033870)

Now we need room temperature sharks

er, but... (1)

Ancient_Hacker (751168) | more than 4 years ago | (#31034348)

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.

Re:er, but... (0)

Anonymous Coward | more than 4 years ago | (#31039220)

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.

Well. We're talking about strained, (extremely) heavily n-doped Germanium. Several important properties of the semiconductor may have changed.

Otherwise, Lasers in the wavelength we're talking about are made of quite exotic semiconductors. Like InGaAsP/InP. If those were the best semiconductors possible, we'd propably use them for things other than lasing.

Nonetheless, they actually say that their efficiency is quite bad.

Nevertheless, they grow this strained germanium stuff on plain silicon. That may mean that it is laughably cheap to produce! Strained silicon is still tricky to manufacture. So this may
be the first practiacal _cheap_ laser grown on Si substrate.

Communication wavelength (1, Insightful)

Anonymous Coward | more than 4 years ago | (#31034472)

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.

Ge (1, Funny)

Anonymous Coward | more than 4 years ago | (#31034980)

you know the Germans always make good stuff.

too many chiefs, not enough indians (0)

Anonymous Coward | more than 4 years ago | (#31035130)

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.

gegen ein totes Pferd (2, Funny)

Tetsujin (103070) | more than 4 years ago | (#31037042)

bedeutet das wir endlich diesen verdammten Haie mit Lasern auf dem Kopf?

room tempreture (0)

Anonymous Coward | more than 4 years ago | (#31037792)

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.

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