Talk:Quantum-cascade laser

message: The statement that electrons are the only charge carrier is ambiguous.  Devices have been successfully demonstrated, which exploit intersubband transitions in the valence band.  Of course, electron transport is taking place here, but one may refer to the process as hole transport when the majority of electron states in a band are occupied.  I think the important point here is that intersubband transitions rather than interband transitions are taking place. - djsik 17:39, 11 March 2006 (UTC)
replies: text: Reading over this, I should probably have said that electroluminescence has been observed for valence band transitions in SiGe.  I'm not so sure about lasing.  Anyway, the point stands that in principle, I'm not aware of a reason why hole transitions  could not be exploited in a QCL.  Anyone else more knowledgeable about this? Alex valavanis 00:04, 2 February 2007 (UTC)
replies: text: Yeah, they've definitely found electroluminesence in IV/IV semiconductors-- no lasing, though. The band jumps simply aren't big enough in SiGe.  —Preceding unsigned comment added by 67.85.179.182 (talk) 09:22, 30 January 2008 (UTC)
replies: text: I'd argue that it's more to do with complexity of the valence bandstructure.  At k=0, the heavy-hole band offset is quite large (~400meV I think) but as you move to non-zero in-plane wave-vectors, increasingly large contributions from the light-hole band are mixed in.  This makes it very difficult to predict the scattering behaviour, reduces the effective band offset and increases the emission linewidth (which kills the gain!)  There's still a chance though, that at very low temperatures it may be possible.  There are also several groups looking at conduction subbands, but no decent experimental results yet.  Papa November (talk) 09:42, 30 January 2008 (UTC)
thread_title: Charge Carriers

message: Although MBE is commonly used, I believe CVD is too.  Does anyone know more about this? - djsik 17:39, 11 March 2006 (UTC)
thread_title: Device Fabrication

message: Orignal concept was published by Kazarinov and Suris in 1971 and then realized by the group at Bell Labs. I think the credit of invention should go to the original authors:
"Possibility of amplification of electromagnetic waves in a semiconductor with a superlattice",Kazarinov, R.F.; Suris, R.A., Fizika i Tekhnika Poluprovodnikov April 1971, vol.5, no.4, pp. 797-800
: Intro now contains the Kazarinov citation. Papa November (talk) 08:52, 19 March 2010 (UTC)
thread_title:  Who is the inventor of QCL? 

message: There are some nice public domain images over on the Netherlands version of this page (nl:Kwantumcascadelaser); would anyone care to have a go at incorporating them here?  — Catherine\talk 08:06, 23 February 2007 (UTC)
thread_title:  Diagrams 

message: The equation starting dn1/dt in the section "Operating Principles" is all wrong. It should read dn1/dt = n2/tau21 + n3/tau31 - n1/tau13 - n1tau12 - Iout
: Papa November (talk) 08:41, 19 March 2010 (UTC)
thread_title:  Major Typos 

message: All QCLs ever published make use of a waveguide. What is this section supposed to mean?  —Preceding unsigned comment added by 192.167.204.12 (talk) 13:35, 28 November 2007 (UTC)
replies: text: You're quite right!  I've tidied it up.  We need to improve this section a lot - there's plenty that can be said about QCL waveguides.  Papa November (talk) 14:25, 28 November 2007 (UTC)
thread_title:  Optical Waveguides  

message: I don't see any significant educational value for keeping this link in the article.  Does anyone see any good reason to include it?  It's important to avoid any advertising or promotion of commercial entities. Papa November (talk) 08:53, 7 May 2011 (UTC)
thread_title:  Daylight Solutions 

message: The statement about 2.75-250 micron "coverage" is misleading... a huge band is missing from the middle of this range (~1-20 THz frequency) owing to Reststrahlen absorption in III-V semiconductors.  If anyone has any references handy, please add this.  Otherwise, I will try to dig something out.  Papa November (talk) 15:41, 13 January 2012 (UTC)
thread_title:  Emission wavelengths 

message: Hello fellow Wikipedians,
I have just modified  on Quantum cascade laser. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
*Added archive http://web.archive.org/web/20051025141307/http://www.bell-labs.com:80/org/physicalsciences/projects/qcl/qcl.html to http://www.bell-labs.com/org/physicalsciences/projects/qcl/qcl.html
*Added archive http://web.archive.org/web/20050418163502/http://www1.bell-labs.com:80/org/physicalsciences/psr/qc/index.html to http://www.bell-labs.com/org/physicalsciences/psr/qc/index.html
*Added archive http://web.archive.org/web/20091026082912/http://www.neoplas-control.com:80/npc/a/Default.aspx?lng=en to http://www.neoplas-control.com/npc/a/Default.aspx?lng=en
When you have finished reviewing my changes, please set the checked parameter below to true or failed to let others know (documentation at ).
Cheers.—InternetArchiveBot (Report bug) 12:42, 21 July 2016 (UTC)
thread_title:  External links modified