Neodymium-yttrium aluminium garnet laser

Figure 1 depicts a commercial instrument. The sample is mounted inside the vacuum chamber of the MS. The DI is commonly performed by 266 nm UV pulses from a frequency-quadrupled Nd YAG (neodymium yttrium- aluminium- garnet) laser. This instrument allows repositioning of the sample and the optics for analysis in transmission or in reflection. In the former case, the laser hits the lower surface of the sample while the upper surface faces the MS. This suits thin films or particles of about 1 [im on a polymer film. Reflection means that the beam impinges on the sample side facing the MS. The surface of bulk samples can thus be characterized. Micropositioners allow one to move the spot of interest on... 

NBTC NC ND Nd YAG ndc NDR NEST NEXAFS Nanobiotechnology Center (Cornell University) nanocrystal nanodiamond neodymium-doped yttrium aluminium garnet (laser) 2,6-naphthalenedicarboxylate 2-nitro-jV-methyl-4-diazonium-formaldehyde resin New and Emerging Science and Technology near-edge x-ray absorption fine structure (spectroscopy)... 

Laser ablation can be carried out on any material without special sample preparation. The laser beam can be directed onto a defined spot of the sample or moved to different parts to analyse over a defined area. It can be moved in an XYZ plane using a stepper motor and driven in translational motions on which the cell is mounted and with more expensive models can be turned for analysis in other parts of the sample. Lasers can operate in UV, visible, and IR regions of the spectrum and a recent development in laser technology uses neodymium yttrium aluminium garnet (Nd YAG) which gives high repetition rate at a comparatively low power. This method of analysis is suited to bulk analysis of solid materials and the amount of volatility varies from sample to sample. The size of the laser spot can vary from 10 to 250 pm and little or no sample preparation is required. Errors are greatly reduced because of the simple sample preparation, and the fact that no solvents are required reduces interferences. 

Solid-state lasers, such as the ruby laser, neodymium doped yttrium aluminium garnet (Nd-YAG) laser and the titanium doped sapphire laser. 

Figure 8.16 illustrates the energy levels of Nd in yttrium aluminium garnet (Y3AI5O12), which are involved in the laser action of this crystal (known as the neodymium YAG laser). Describe the processes that occur when the laser is working. 

Laser Ablation [7]. The modern method for quantitative solid analyses is carried out using a laser ablation technique (Figure 2.16). The laser, usually in the form of Nd YAG (Neodymium - Doped Yttrium Aluminium Garnet), is focused on to the surface of a sample which, by continuous pulsing, leads to vaporisation at that point and the vapour is transported directly to the plasma with argon for detection and quantification. Detection limits are... 

Laser based on neodymium-doped yttrium-aluminium garnet. The emission wavelength is 1,064 nm, the power can be up to several tens of W. Mode-synchronisation delivers picosecond pulses at a repetition rate of 50 to 100 MHz. 

For all their usefulness, gas lasers are very inefficient lasers, with normally much less than 0.1 per cent conversion of electrical energy into laser light. A very widely used solid-state laser material is Nd YAG (and various similar doping/host material combinations). The abbreviation Nd YAG stands for neodymium atoms (Nd) being implanted in an yttrium aluminium garnet crystal host (Y3AI5O12). These implants, in the form of triply ionized neodymium Nd, form the actual active laser medium. 

---