Neodymium-doped yttrium aluminum garnet Nd:YAG laser

Many real-world samples fluoresce when iUuminated with visible light, especially green light from a frequency-doubled neodymium-doped yttrium aluminum garnet (Nd-YAG) laser at 532nm or from an argon ion laser at 488 or 514.5nm. 

In a solid state laser, the active species is distributed throughout a solid, usually crystalline, material, although glass can also be used as a host. The lasers are robust and frequently tunable, though heat dissipation can sometimes be an issue. Certain types of solid state crystals, for example neodymium-doped yttrium aluminum garnet (Nd YAG), can be pumped by diode lasers instead of by other lasers or by flashlamps, which is often the case for other materials. Such diode-pumped, solid state systems are reliable, economical, compact, and easy to operate—in fact, many commercial systems are turnkey, needing only to be plugged in and turned on to operate. 

Neodymium-doped yttrium aluminum garnet laser (Nd YAG)... 

Before the invention of lasers in 1960 (Maiman), radiation emitted by the mercury arc, especially at 435.8 and 404.7 nm, has been u.sed for exciting Raman spectra (Brandmiiller and Moser, 1962). Today, most types of lasers ( continuous wave (cw) and pulsed, gas, solid state, semiconductor, etc.), with emission lines from the UV to the NIR region, are used as radiation sources for the excitation of Raman spectra. Especially argon ion lasers with lines at 488 and 515 nm are presently employed. NIR Raman spectra are excited mainly with a neodymium doped yttrium-aluminum garnet laser (Nd YAG), emitting at 1064 nm. 

Nd YAG neodymium-doped yttrium aluminum garnet, (a typical solid laser... 

One type of laser used in the treatment of vascular skin lesions is a neodymium-doped yttrium aluminum garnet or Nd YAG laser. The wavelength commonly used in these treatments is 532 mn. 

One of the most widely used lasers today is the yttrium-aluminum-garnet (YAG) laser. YAG lasers often contain other elements. These elements change the kind of light produced by the laser in one way or another. The laser is said to be doped with another element if it contains a small amount of that element. An example of this kind of laser is one doped with neodymium. The neodymium-doped YAG (Nd YAG) laser has been used to make long distance measurements. 

In Figure 20.19 we sketch the operation of the neodymium-YAG laser. The laser medium is a crystal of yttrium-aluminum-garnet doped with neodymium ions. This laser has the advantage over the ruby laser that the laser action occurs between two excited states, and the population inversion is consequently easier to maintain. The Nd-YAG laser is widely used in science and technology. One major application is to pump the so-called dye lasers in which the medium is intensely colored dye molecules (usually with conjugated double bonds) dissolved in... 

Thus, a high frequency excitation source enhances the number of scattered Raman photons dramatically. As an example, let us consider the relative intensity of a 1000 cm Raman line excited at 1064 nm and also excited at 514 nm. The first wavelength is available from an Nd YAG (yttrium aluminum garnet doped with neodymium) diode laser, and the second from an argon ion laser. Using the excitation at 1064 nm the 1000 cm Raman band occurs at 1191 nm, and for the excitation at 514 nm the Raman line would occur at 542 nm. Therefore, the enhancement of the 514 nm excitation relative to the 1064 nm excitation would be by a factor (1191/542)" = 23.3. This means that there are 23.3 times as many photons to detect with the shorter wavelength excitation simply as a consequence of the nature of the scattering process. This can be a very important effect. 

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