The contents of the Terahertz gap page were merged into Terahertz radiation on 25 August 2022. For the contribution history and old versions of the redirected page, please see its history; for the discussion at that location, see its talk page. |
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A news item involving Terahertz radiation was featured on Wikipedia's Main Page in the In the news section on 17 May 2012. |
The contents of the Tremendously high frequency page were merged into Terahertz radiation on March 2, 2014. For the contribution history and old versions of the redirected page, please see its history; for the discussion at that location, see its talk page. |
Radio wave redirects to Radio frequency, which is (according to the spectrum guide at the bottom of the page) the name for electromagnetic radiation with a far longer wavelength. Can someone more knowledgable than me please clarify or rephrase this appropriately? - Fourohfour 19:17, 21 September 2005 (UTC)
is it really necessary to link back to the same page within the 10 first words? - 81.216.34.35, at 08:47, 7 April 2006
well i am a novice to this subject. so can any one tell me what defines terahertz technology? —The preceding unsigned comment was added by 202.56.231.116 (talk • contribs) 02:10, 30 July 2006 (UTC)
Ok I get it but what's with this fuss about Terahertz 'Technology'; what differentiates it from usage of other waves in electromagnetic spectrum notfew years back INTEL anounced it is using some application of terherts tecnology in its processor so what does it differ from conventional electronic devices used such as diodes transistrors etc and can u tell me its other applications that is't mentioned here — Preceding unsigned comment added by Backar19 (talk • contribs) on 17:17, 31 July 2006 (UTC)
The suggestion that THz technology can replace mammography and penetrate several cm of water 'at some THz frequencies' is simply wrong.
Anywhere above 100GHz the absorption depth in water is 100 microns or less. Transmission through cm of water of flesh yields huge attenuations, such tht here is no possibility, with any source or detector, of making a system; attenuations typically eceed 10^30!
Redefining <100GHz or 10um ('30THz') as terahertz technology is simply spurious; the first is routine microwave, the second mid infrared.
These ridiculous claims were prominent some years ago but at last are dissappearing! — Preceding unsigned comment added by Hnrutt (talk • contribs) on 06:54, 25 September 2006 (UTC)
One terahertz is Hz. Conventionally the microwave band extends to 30 GHz or so. While the far-IR is nominally reckoned to start at around 1 THz. So the terahertz band lies between micowaves and the far-IR. On the other hand, in this frequency range the wavelengths of electromagnetic waves (in vacuum) are millimeter or sub-millimeter. So, logically, terahertz waves are the same thing as millimeter or submillimeter waves. However, in practice people who use the term terahertz are generally speaking of signals generated by ultrafast optical techniques or far-IR lasers. Focusing a sub-picosecond pulse on a photoconductive antenna of suitable dimensions will produce EM waves in the THz band. On the other hand, people who use the term millimeter or submillimeter waves are invariably speaking of sources and detectors based on harmonic multiplication of microwave signals.
There have been commercial solid-state sources of millimeter and submillimeter waves for many years. AB Millimeter in Paris, for instance, produces a system that covers the entire range from 8 GHz to 1000 GHz with solid state sources and detectors. Nowadays, most time-domain work is done via ultrafast lasers. One of the key application of millimeter and submillimeter waves is the study of condensed matter in high magnetic fields since at high fields (say above 15 T), the Larmor frequencies are in the submillimeter band. —The preceding unsigned comment was added by 69.3.54.170 (talk • contribs) 04:22, 4 December 2006 (UTC).
I'm afraid that the wrong part of the spectrum: instead of a band between visible and infrared, it should point between infrared and microwaves, as said in the text —Preceding unsigned comment added by 130.226.31.168 (talk) 00:12, 18 January 2009 (UTC)
I've now uploaded a better version of the diagram with the infrared band inserted. 84user (talk) 00:45, 28 May 2009 (UTC)
I notice that the "inexpensive sources exist in the 300-1000 GHz range" line has been tagged as needing a citation. It's going to be tough to find a direct citation for it, but it's very easy to demonstrate that it's correct. What sort of citations would be appropriate under those conditions?
Gyrotrons are cheap and high-power, widely used in t-wave experiments and for the "pain ray" that made the news a while back, but the highest frequency I've heard of is about 300 GHz. Tunnel diode oscillators are cheap and low- to medium-power, have been making the news recently, and are also widely used in experiments, but the highest frequency I've heard of is around 600 GHz. Sources that produce higher frequencies tend to involve very bulky and expensive lasers, or extremely bulky and expensive particle beams (for the free-electron laser and synchrotron sources). (A quantum cascade laser is not bulky, but _is_ quite expensive.) The only source listed that I'm not very familiar with is the backward wave oscillator, which runs at 1000 GHz and below at low power, and which I'd expect to be fairly inexpensive (like the gyrotron, it's a vacuum tube device).
I can find individual research papers using all of these devices, but finding one that says "to generate t-waves above 1000 Ghz, you need Foo types of source" will be very difficult, and none will mention the cost of the source, meaning use of such references to support a cost statement would be WP:SYN. If anyone has a more appropriate source, by all means suggest or cite it. --Christopher Thomas (talk) 19:38, 18 May 2012 (UTC)
A user commented that the atmospheric transmission figure needed to specify a pathlength in order for percent transmission to be meaningful. I believe the figure is okay as it is because it is the penetration through earth's atmosphere from a particular location. The pathlength, therefore, is the "thickness" of the atmosphere from that point.ronningt (talk) 15:48, 19 May 2012 (UTC)
The second paragraph in the introduction part says:
The earth's atmosphere is a strong absorber of terahertz radiation in specific water vapor absorption bands, as seen in the two figures heading this article
The figures aren't there anymore and this needs to be fixed. Also it says ALMA is under construction in Sources > Natural! Also I don't get why Sources > Natural has a list of telescopes. Tushar Shrotriya (talk) 07:29, 23 January 2014 (UTC)
There are two paragraphs about imaging that erroneously appear in the "Sources" section:
I moved them into more appropriate locations in the "Research" section, but a recent editor moved them back. KiarashKevin, these are obviously not about "sources" of terahertz radiation, right?. If they are going to be in the article, they should be in the "Research" section. Also, when you make an edit, you should give a brief edit summary (in the text box appearing under the main edit box) to explain it, see WP:EDIT SUMMARY. --ChetvornoTALK 22:00, 4 July 2015 (UTC)
Can someone with domain knowledge speak to the information presented in this paper? http://arxiv.org/pdf/0910.5294v1.pdf — Preceding unsigned comment added by 2600:1004:B018:B0FA:2487:4132:C486:2AEB (talk) 18:01, 23 September 2015 (UTC)
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I am considering converting a part of my PhD thesis (https://github.com/FilipDominec/thesis) into the wiki format. In particular, I think we could replace a part of this article with an excerpt from my thesis, which can be in preliminary form found here: User:FDominec/THz_sources_and_detectors. I believe I wrote the text in a slightly more systematic and detailed manner than in this article. What do you think, will this be useful? --FDominec (talk) 11:07, 7 July 2017 (UTC)
In this part of wikipedia THz is defined as the radiation between 0.3 THz and 3 THz, for me THz is between 1 THz and 10 THz. But this is an opinion and there is no official definition. So if we suppose that the radiation start at 0.3 THz, we are speaking of 1 mm wavelenght radiation. Following the Wien's law at 10 K the peak of emission of a black body is at wavelenght 289 μm. So to be coherent I changed the temperature from 10 K to 2 K: in fact 0.3 THz is the peak of the Big_Bang radiation temperature 2.725 K. Pasquale.Carelli (talk) 14:27, 6 September 2017 (UTC)
There is a Research section - Could we also start an Applications section (maybe including research tools and radio astronomy ?). - Under Research/Potential-applications we could have THz radar for low-visibility as in Terahertz (THz) Radar: A Solution For Degraded Visibility Environments (DVE) - Rod57 (talk) 23:13, 1 December 2017 (UTC)
context and wide overlap fgnievinski (talk) 06:10, 6 February 2022 (UTC)
I was surprised not to see any mention of sparks. They generate everything from radio to ultraviolet. oldrider (talk) 20:33, 25 October 2022 (UTC)