Obtaining Ultraviolet Output with CLBO Crystal

Reaching the UV with CLBO

Generating ultraviolet output by frequency conversion gets harder as the wavelength shortens: crystals absorb more, phase matching narrows, and the high-energy UV photons damage the material. CLBO (CsLiB₆O₁₀) is engineered for exactly this regime, transmissing down to ~180 nm and supporting efficient phase matching for 266 nm (fourth harmonic of Nd:YAG) and shorter wavelengths via further sum-frequency mixing.

How UV output is obtained

A typical Nd:YAG-based UV chain starts with the 1064 nm fundamental, doubles it to 532 nm green, triples to 355 nm, then quadruples to 266 nm using CLBO. With additional mixing, CLBO can reach ~236 nm and below. CLBO's wide angular/spectral acceptance and small walk-off make these high-order conversions more efficient and alignment-forgiving than BBO at the same wavelengths.

Applications of CLBO UV output

CLBO-produced DUV serves semiconductor inspection and lithography-related metrology, fine micromachining, UV Raman and fluorescence spectroscopy, and biosensing. For the 355 nm stage, LBO/BBO are typical; CLBO owns the 266 nm and shorter range. See our CLBO crystals and the CLBO deep-UV article.

Frequently asked questions

Why CLBO for 266 nm? Its UV transparency, wide acceptance, small walk-off and high damage threshold give more 266 nm output at higher power than BBO.

Can it go below 266 nm? Yes — via further mixing CLBO reaches ~236 nm and shorter for advanced DUV sources.

Handling? CLBO is hygroscopic and needs a dry, temperature-stabilised cell.