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Cavity ring-down spectroscopy (CRDS)

The Nd:YAG may be used in the application of cavity ring-down spectroscopy, which is used to measure the concentration of some light-absorbing substance.

Laser-induced breakdown spectroscopy (LIBS)

A range of Nd:YAG lasers are used in analysis of elements in the periodic table. Though the application by itself is fairly new with respect to conventional methods such as XRF or ICP, it has proven to be less time consuming and a cheaper option to test element concentrations. A high-power Nd:YAG laser is focused onto the sample surface to produce plasma. Light from the plasma is captured by spectrometers and the characteristic spectra of each element can be identified, allowing concentrations of elements in the sample to be measured.

Additional frequencies

For many applications, the infrared light is frequency-doubled or -tripled using nonlinear optical materials such as lithium triborate to obtain visible (532 nm, green) or ultraviolet light. Cesium lithium borate generates the 4th and 5th harmonics of the Nd:YAG 1064 nm fundamental wavelength. A green laser pointer is a frequency doubled Nd:YVO

4 DPSS laser. Nd:YAG can be also made to lase at its non-principal wavelength. The line at 946 nm is typically employed in "blue laser pointer" DPSS lasers, where it is doubled to 473 nm.

Physical and chemical properties of Nd:YAG

Properties of YAG crystal

• Formula: Y

3 Al

5 O

12

• Molecular weight: 596.7

• Crystal structure: Cubic

• Hardness: 8–8.5 (Moh)

• Melting point: 1950 °C (3540 °F)

• Density: 4.55 g/cm 3

Refractive index of Nd:YAG

Wavelength (μm) Index n (25°C)

0.8 1.8245

0.9 1.8222

1.0 1.8197

1.2 1.8152

1.4 1.8121

Properties of Nd:YAG @ 25°C (with 1% Nd doping)

• Formula: Y

2.97 Nd

0.03 Al

5 O

12

• Weight of Nd: 0.725%

• Atoms of Nd per unit volume: 1.38×10 20 /cm 3

• Emission wavelength: 1064 nm

• Transition: 4 F

3/2 → 4 I

11/2

• Duration of fluorescence: 230 μs

• Thermal conductivity: 0.14 W·cm -1 ·K -1

• Specific heat capacity: 0.59 J·g -1 ·K -1

• Thermal expansion: 6.9×10 -6 K -1

• d n /d T : 7.3×10 -6 K -1

• Young's modulus: 3.17×10 4 K·g/mm -2

• Poisson's ratio: 0.25

• Resistance to thermal shock: 790 W·m -1