Nd: YAG Laser

Nd: YAG laser are the most popular type of solid state laser. The laser medium is a crystal of Y₃Al₅O₁₂ which are commonly called YAG, an acronym for yttrium aluminum garnet. A simplified energy-level scheme for Nd:YAG is shown in Fig. 1. The λ=1.06 μm laser transition is the strongest of the 4F_3/2→4I_11/2 transitions.

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Fig. 1. Schematic of Ruby laser

Figure 2. Simplified energy level diagram of the⁴F_3/2---⁴I_11/2 laser transition in Nd:YAG showing the four- level nature of the system

The major application of the Nd laser is in various form of material processing: drilling, spot welding, and laser marking. Because they can be focused to a very small spot, the laser are also used in resistor trimming and in circuit mask , memory repair and also in cutting out specialized circuits. Medical applications include many types of surgeries. Many medical applications take advantage of low-loss optical fiber delivery systems that can be inserted into the body to wherever is needed. Nd lasers are also used in military applications such as range finding and target designation. High power pilsed versions are also used for X-ray spectral regions. In addition, Nd lasers are used in scientific lab as good sources for pumping dye laser and other types of lasers.