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Spectral Ranges

Most of the imaging for industrial and scientific applications involves detecting visible radiation and the bulk of equipment available for imaging cover this band.  Hoowever, the visible is only a very small part of the usable electromagnetic spectrum covering just less than an octave near the center of the full range.


This chart shows the wavelengths corresponding to large bands of the spectrum.  From one nanoometer down, the radiation is termed "X-rays" with the shorter wavelengths in this band and below dubbed "Cosmic Rays" due to our inability to produce them synthetically; they originate entirely from space.   From 1 millimeter up are the various communications bands covering everything from radar to subsea VLF links.  Various other equipment like microwave ovens also operate in this band, although the "microwaves" used in them actually have wavelengths of tens of centimeters.  We will not discuss this part of the spectrum because generation and detection of radiation at these wavelengths usually involves direct use of the electric and magnetic fields rather than photon processes. 

Information on each of the four non-visible bands is provided on four separate pages.  Click these links to see them:

X-ray | Ultraviolet | Infrared | Terahertz

Frequency and Photon Energy Equivalents

Radiation in particular bands may more commonly be referred to by frequency or photon energy.  This table shows the equivalents for the range in the chart above.

Wavelength (m) Frequency (Hz)
   Energy (J)  
Energy (eV)
10 pico 30 exa
19 femto
120 kilo
 100 pico
 3 exa
1.9 femto
12 kilo
 1 nano
 300 peta
 190 atto
1.2 kilo
 10 nano
 30 peta
19 atto
 100 nano
3 peta
1.9 atto
 1 micro
 300 tera
190 zepto
 10 micro
 30 tera
19 zepto
120 milli
 100 micro
3 tera
1.9 zepto
12 milli
1 milli
 300 giga
190 yocto
1.2 milli