Attaining 186-nm light generation in cooled ?-BaB_2O_4 crystal

Abstract

The transparency range of beta-BaB(2)O(4) (BBO) was expanded by means of cooling, and the resulting absorption coefficient at 193.4 nm was reduced to 0.29cm(-1) at 91 K from 1.39cm(-1) at 295 K. Further, generation of light at 186.0 nm (the measurement limit in air) by type I sum-frequency generation (SFG) based on fundamental (744-nm) and third-harmonic (248-nm) light from a Ti:sapphire laser was confirmed for cooled BBO. Calculations based on observed data for SFG wavelengths and phase-matching angles indicate a potential for cooled BBO to generate wavelengths as low as 181.7 nm.

Thermal effects in high average power optical parametric amplifiers

“…However, both nonlinear (temperature bandwidth of phase matching) and thermo-optical properties (absorption, thermal conductivity, fracture strength) need to be considered and traded-off for each specific application. Cryogenic cooling of the nonlinear crystals might be worth future investigations [19]. In this regard precise measurements of the absorption coefficients and the thermal conductivity of the nonlinear crystal materials over a large temperature range will be indispensable.…”

A solid-state 193-nm laser with high spatial coherence for sub-40-nm interferometric immersion lithography

“…The flux-grown BBO crystal is uncoated and contained in a dry atmosphere within a sealed housing. A four-stage TEC (Melcor, NJ) is used to cool the BBO SFM crystal to a temperature of 226 K. The benefits derived from cooling the BBO are described elsewhere [3,4], but briefly such cooling reduces the 193 nm absorption by ~50% and improves the phase-matching stability. The 193-nm light is separated from the other wavelengths by use of a Pellin-Broca prism, and propagates through ~3 m air prior to entering the IIL apparatus.…”

All-solid-state Q-switching ultraviolet light Nd:YAG laser

“…Where L is crystal length, Zeff 5 the second effective nonlinear coefficient of crystal, , 2 3 are intensity of three waves, fl1 , ' 3 are the reflectivity of the waves in crystal respectively., AK is phase-match coefficient , AK = K3 - 2 1 Ultraviolet light at 355nm is obtained using the fundamental wave at 1064nm and its frequency doubled wave at 532nm from QCWLD Pumped Q-switched Nd:YAG laser. We use BBO crystal to generate third harmonic radiation (THG).…”