WHAT IT IS
The Nd:YAG 266 nm laser ablation system is a solid-state laser source used in laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). It is based on a neodymium-doped yttrium aluminum garnet (Nd:YAG) crystal operating at 1064 nm, frequency-quadrupled to produce ultraviolet output at 266 nm. Although less efficient than 213 nm or 193 nm lasers in many matrices, the 266 nm wavelength still provides adequate absorption for a variety of materials. Its robustness, lower cost, and availability make it a practical option for routine elemental and isotopic analysis, particularly in laboratories with broader material types and less demanding precision requirements.
HOW IT WORKS
Laser Generation - The Nd:YAG crystal produces fundamental infrared output at 1064 nm. Nonlinear crystals convert the frequency to 266 nm in the UV range.
Beam Delivery - Mirrors and focusing optics direct the beam into the ablation chamber. Spot sizes from 5–200 µm allow both large-area ablation and microanalysis.
Sample Interaction - The 266 nm UV light is absorbed moderately by many materials. Compared with 213 or 193 nm lasers, absorption is lower, leading to stronger thermal effects, more melting, and less stoichiometric particle release.
Aerosol Transport - Ablated particles are swept by helium or argon gas to the ICP torch. Particle distribution tends to be coarser and less uniform than with shorter-wavelength lasers.
Detection - In the ICP, particles are atomized and ionized. The mass spectrometer records ion signals to provide elemental concentrations and isotope ratios.
ADVANTAGES
Robust Technology: Solid-state design with relatively simple optics compared to excimer systems.
Cost-Effective: Less expensive than 213 nm Nd:YAG or 193 nm excimer lasers.
Broad Usability: Capable of ablating a wide range of minerals, metals, and synthetic solids.
Flexible Spot Size: Suitable for bulk ablation and moderate-resolution mapping.
Ease of Maintenance: Fewer consumables and lower service requirements than gas-based excimer lasers.
CHALLENGES AND LIMITATIONS
Elemental Fractionation: Stronger thermal effects at 266 nm increase melting and non-stoichiometric transfer.
Matrix Dependence: Absorption efficiency varies significantly between materials, complicating quantification.
Resolution: Limited spatial resolution compared with 213 nm or 193 nm systems.
Competitiveness: Superseded by 213 nm Nd:YAG and 193 nm excimer lasers in high-precision geochemical and isotopic work.
Particle Characteristics: Larger and less uniform aerosol particles reduce transport efficiency and sensitivity.