Reliability of Czochralski-grown B-BaB2O4 (BBO) devices

Umezu, Nobuhiko; Fukui, Taro; Okamoto, Tatsuyuki; Wada, Hiroo; Tatsuki, Koichi; Kondo, Kenji; Kubota, Shigeo

doi:10.1117/12.306988

Cited by 5 publications

(3 citation statements)

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“…One aspect of BBO crystals, however, that has not received much attention is the role of point defects in either enhancing or limiting device performance. Several reports in the literature have described the response of BBO crystals to high-intensity, ultraviolet laser beams, including thermal dephasing effects [11], operational lifetimes [12], and twophoton absorption [13]. Additional studies have focused on characterization of absorbing defects (both impurities and native colour centres) in BBO crystals [14][15][16][17][18][19][20][21][22][23][24].…”

Section: Introductionmentioning

confidence: 99%

Electron paramagnetic resonance study of Ag⁰atoms and Ag²⁺ions in -BaB₂O₄nonlinear optical crystals

Wang

Perlov

Halliburton

2003

J. Phys. D: Appl. Phys.

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Silver ions have been diffused into single crystals of β-BaB2O4 (commonly referred to as BBO). The crystals were wrapped in silver foil and then held in air at 760°C for periods of time ranging from 1 to 7 h. This treatment resulted in Ag+ ions occupying both Ba2+ sites and interstitial sites within the crystal. After the diffusion, the crystal was irradiated at room temperature with 60 kV x-rays. Three distinct paramagnetic defects, one holelike and two electronlike, were produced by the x-rays and observed with electron paramagnetic resonance (EPR) at temperatures between 15 and 80 K. The Ag+ ions substituting for Ba2+ ions trapped radiation-induced holes and became paramagnetic Ag2+ ions. At the same time, interstitial Ag+ ions trapped electrons and became paramagnetic Ag0 atoms. There are two distinct versions of these latter centres. The EPR spectra of the Ag0 atoms show resolved hyperfine from the 107,109Ag isotopes, as well as from a neighbouring nucleus (possibly a Na+ impurity substituting for a Ba2+ ion). All the radiation-induced EPR signals were stable at room temperature for hours.

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Section: Introductionmentioning

confidence: 99%

Electron paramagnetic resonance study of Ag⁰atoms and Ag²⁺ions in -BaB₂O₄nonlinear optical crystals

Wang

Perlov

Halliburton

2003

J. Phys. D: Appl. Phys.

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“…Berkeland et al showed 2 W CW light at 257 nm generated in an external bow-tie resonator with a Brewster-cut BBO, but no statement on the long-term stability was given [2]. At 266 nm Kondo et al demonstrated long-term operation for 1000 h with 100 mW output power, provided that the fundamental power was increased during this time of operation [9,20]. For the mercury 6 1 S 0 -6 3 P 1 trans ition at 253.7 nm Scheid et al described a frequency quadrupled solid state system with a stable output of 400 mW [14].…”

Section: Introductionmentioning

confidence: 99%

Non-degrading CW UV generation in β-barium borate at 257 nm using an elliptical focusing enhancement cavity

Kiefer¹,

Preißler²,

Führer³

et al. 2019

Laser Phys. Lett.

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With a combination of an elevated temperature for the β-barium borate (BBO) crystal and an elliptical focusing cavity we succeeded in eliminating the degradation in BBO during second harmonic generation into the ultraviolet (UV). We were capable of generating over 600 mW continuous-wave UV light at 257 nm with an off-the-shelf crystal for over 8 h without any sign of degradation. Our results indicate that the degradation is caused by color centers generated by two-photon absorption (TPA) strongly increasing the absorption of the fundamental radiation. While the higher crystal temperature reduces the TPA coefficient and the life time of the color centers, elliptical focusing strongly reduces the peak irradiance of the fundamental and thus its absorption.

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“…Several previous works argued that the CZ-grown BBO had better properties when used for frequency conversion to the UV. Umezu and al reported in 1998 that CZ-BBO lead to an improved laser lifetime, but without showing any material characterization [6]. In 2012, Bandhari and al reported a 3 MW peak power 266nm microchip laser based on fluxless-grown BBO.…”

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confidence: 99%

Impact of BaB2O4 growth method on frequency conversion to the deep ultra-violet

Deyra

Maillard

et al. 2015

Solid State Sciences

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To cite this version:Loic Deyra, Alain Maillard, R Maillard, D Sangla, F Salin, et al.. Impact of BaB 2 O 4 growth method on frequency conversion to the deep ultra-violet. Solid State Sciences, Elsevier, 2015, 50, pp.97-100. 10 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Czochralski and TSSG β-BBO crystals are compared for high power UV (266nm) in second harmonic generation. Impurities from flux decrease the efficiency of harmonic generation at high power (40%). Corresponding author : A Maillard, alain.maillard@univ-lorraine.fr M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT Impact of BaBAbstract: In this article, we report how the growth method used for barium beta-borate β−BaB2O4 (BBO) impacts its high power second harmonic generation properties in the deep-UV. We compared a BBO crystal grown by flux (Top Seeded Solution Growth or TSSG) and a BBO crystal grown by the Czochralski (CZ) method. We first characterized their transparency properties, then we measured their single-pass second harmonic conversion efficiencies with both a low average power and a high average power nanosecond pulsed lasers. We show that both crystals have comparable linear absorption and conversion efficiencies at low power, whereas in a high power experiment, the CZ-grown BBO yields higher conversion efficiency than the TSSG grown BBO. With a 30 W, 150 kHz, 8ns green laser, the use of a CZ BBO led at best to a 40% increase in available average output power at 257 nm.Keywords: Borates, Nonlinear optical, Czochralski growth, Solution growth, Second harmonic generation. IntroductionThe material machining industry has continuously looked to process more and more types of materials efficiently. For some of them such as silicon, glass, sapphire, the ultraviolet lasers (UV) were developed in order to increase the material absorption [1,2]. While UV lasers around 350 nm obtained by third harmonic generation (THG) are now commonly used in material processing, deep-UV lasers obtained by fourth harmonic generation (FHG) around 260 nm are still challenging to realize. The nonlinear material quality is a key parameter in order to reach high and stable conversion efficiency by reducing thermal dephasing and degradation effects. Beta-barium borate β-BaB2O4 (BBO) is a nonlinear crystal that has good properties for frequency conversion to the UV, such as a high nonlinearity or a short cut-off wavelength in the UV around 190nm [3]. It is available commercially, and is usually grown by top-seeded solution growth (TSSG) assisted with either a Na2O or NaF flux [4]. BBO can be also grown without flux by the Czochralski (CZ) method, but...

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Reliability of Czochralski-grown B-BaB2O4 (BBO) devices

Cited by 5 publications

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Electron paramagnetic resonance study of Ag⁰atoms and Ag²⁺ions in -BaB₂O₄nonlinear optical crystals

Electron paramagnetic resonance study of Ag⁰atoms and Ag²⁺ions in -BaB₂O₄nonlinear optical crystals

Non-degrading CW UV generation in β-barium borate at 257 nm using an elliptical focusing enhancement cavity

Impact of BaB2O4 growth method on frequency conversion to the deep ultra-violet

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Reliability of Czochralski-grown B-BaB2O4 (BBO) devices

Cited by 5 publications

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Electron paramagnetic resonance study of Ag0atoms and Ag2+ions in -BaB2O4nonlinear optical crystals

Electron paramagnetic resonance study of Ag0atoms and Ag2+ions in -BaB2O4nonlinear optical crystals

Non-degrading CW UV generation in β-barium borate at 257 nm using an elliptical focusing enhancement cavity

Impact of BaB2O4 growth method on frequency conversion to the deep ultra-violet

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Electron paramagnetic resonance study of Ag⁰atoms and Ag²⁺ions in -BaB₂O₄nonlinear optical crystals

Electron paramagnetic resonance study of Ag⁰atoms and Ag²⁺ions in -BaB₂O₄nonlinear optical crystals