Two-photon absorption of KBe₂BO₃F₂and CsLiB₆O₁₀at 193 nm

Abstract

We measured the two-photon absorption coefficients of KBe2BO3F2 (KBBF) and CsLiB6O10 (CLBO) at 193.5 nm using CaF2 as a reference. This is the first report about KBBF measurement at any wavelength. The two-photon absorption coefficients of KBBF, CLBO, and CaF2 were 1.3 × 10−9, 1.0 × 10−9, and 0.8 × 10−9 cm/W, respectively. We also measured the fluorescence spectra of KBBF, CLBO, and CaF2 excited by 193.5 nm light. The observed spectrum of KBBF had a broad peak at 322 nm, similar to that of CaF2. The luminescence intensity showed a quadratic dependence on incident laser intensity for KBBF and CaF2, indicating a two-photon process, but showed a linear dependence for CLBO. Taken together, we conclude that the two-photon fluorescence of KBBF originates, as in the case of CaF2, from the transition of a self-trapped exciton formed by a F2− ion (self-trapped hole), which captures an electron.

High Efficiency Third-Harmonic Generation in a Medium with Quadratic Susceptibility Due to Cubic-like Nonlinearity Caused by Cascaded Second-Harmonic Generation

“…The absorption coefficient may change from quite a high value (0.1 cm −1 ) for the ADP crystal and (0.03 cm −1 ) for the KDP crystal to a very low value (<0.001 cm −1 ) for the BBO crystal for the optical pulse with a wavelength λ 1 = 1064 nm [68]. At λ 3 = 353 nm, the absorption coefficient of the KDP crystal is lower at 0.003 cm −1 , and of the KBBF crystal is 0.1 cm −1 at the optical pulse wavelength 330 nm [69]. Therefore, the absorption can be neglected in some cases.…”

Photoluminescence and scintillation characteristics of β-BaB2O4 single crystal

“…Following these successes, some bright scintillators such as Cs 2 HfCl 6 , 35) families of the Cs 2 LiYCl 6 series, 36) Tb 3 Al 5 O 12 , 37) TlMgCl 3 , 38) Ba-based complex anion materials, 39) KSr 2 I 5 , 40) and CsLiB 6 O 10 (CLBO) 41) have been found. Although most materials were developed for scintillator purposes, CLBO was developed as a nonlinear optical material and a very famous one in nonlinear optics, [42][43][44][45][46][47][48][49] and we were surprised that CLBO showed a very high scintillation light yield. 41) To our knowledge, CLBO has the highest scintillation light yield among undoped materials ever reported.…”

“…50) It has a very wide range of transparency from 200 nm to 2.6 μm, 51) and it can be applied for fourth harmonic generation (266 nm) of Nd-doped YAG lasers. Following the invention of β-BBO, other common borate nonlinear materials such as CLBO [42][43][44][45][46][47][48][49] and LiB 3 O 5 (LBO) 52) were invented. Up to now, although many investigations have investigated the optical nonlinear properties of β-BBO, [53][54][55] the scintillation properties have been rarely studied.…”