Talk:Terahertz radiation

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[edit] When is a radio wave not a radio wave?

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)

The term 'radio wave' is used interchangably with 'radio frequency', to refer to frequency bands commonly used for radio transmission (or any other frequencies in that neighborhood). This would encompass everything from quite low frequencies (i.e., kilohertz) up to the microwave range (a few gigahertz or even up to 100 gigahertz, depending on who you ask). But everybody agrees that all of these frequencies are lower than 1 terahertz (since 1 terahertz = 1000 gigahertz = 1,000,000 megahertz). Since wavelength is the reciprocal of frequency (more precisely, wavelength * frequency = speed of light, which is constant), higher frequencies have shorter wavelengths. Thus, radio waves (lower frequencies) always have longer wavelengths than terahertz radiation. And, similarly, terahertz radiation has a longer wavelength than visible light, since the frequency is lower.
Does that answer your question? - 23:25, 31 December 2005 70.240.176.127

[edit] Recursive link

is it really necessary to link back to the same page within the 10 first words? - 08:47, 7 April 2006 81.216.34.35

Not at all. Rainwarrior 02:35, 2 May 2006 (UTC)

[edit] defining the subject

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)

I don't know what I could tell you that's not in the article lead. It's anything using very high frequency electromagnetic waves (particularly, ones in the Terahertz band). - Rainwarrior 15:19, 30 July 2006 (UTC)

CLARIFICATION NEEDED 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

[edit] THz and tissue/water penetration.

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!

Clarification: Since tissue is not 100% water, it can be possible to look through >1cm of certain tissue, if it contains relatively little water. But e.g. mammography will not work. --129.13.186.1 (talk) 17:55, 28 January 2008 (UTC)

[edit] THz versus millimeter and submilleter waves

I added a discussion of the distinction between millimeter/submillimeter waves and terahertz waves. I also mentioned the use of solid state sources and detectors which have been around for many years. Finally I included the two biggest current applications of submillimeter waves that I'm aware of, astrophysics and high-magnetic field (EPR, ESR). Csmmpl 04:39, 4 December 2006 (UTC)