Short UV Research Articles

Laser-induced incandescence applied to dusty plasmas

This paper reports on the laser heating of nanoparticles (diameters μm) confined in a reactive plasma by short (150 ps) and intense ( mJ) UV (355 nm) laser pulses (laser-induced incandescence, LII). Important parameters such as the particle temperature and radius follow from analysis of the emission spectrum of the heated nanoparticles. The nanoparticles are not ideal black bodies, which is taken into account by calculating their emissivity using a light-scattering theory relevant to our conditions (Mie theory). Three sets of refractive index data from the literature serve as model input.The obtained radii range between 100 and 165 nm, depending on the choice of refractive index data set. By fitting the temperature decay of the particles to a heat exchange model, the product of their mass density and specific heat is determined as J K−1 cm−3, which is considerably smaller than the value for bulk graphite at the temperature our particles attain (3000 K): 4.8 J K−1 cm−3.The particle sizes obtained in situ with LII are compared with ex situ scanning electron microscopy analysis of collected particles. Quantitative assessment of the LII measurements is hampered by transport of particles in the plasma volume and the fact that LII probes locally, whereas the samples with collected particles have a more global character.

Be2BO3F: A Phase of Beryllium Fluoride Borate Derived from KBe2BO3F2 with Short UV Absorption Edge.

A phase of beryllium fluoride borate Be2BO3F (BBF) was successfully developed and grown by spontaneous nucleation from high temperature solution. The crystal belongs to the trigonal space group of R3̅c (No. 167), with lattice parameters a = 4.442(1) Å, c = 24.956(5) Å, and Z = 2. It is constructed by the infinite planar [Be2BO3F2]∞ layers, in which the planar triangle [BO3](3-) and the tetrahedral [BeO3F](5-) anionic groups are arranged in parallel via corner-sharing O atoms in each ab plane. BBF is an incongruent compound and decomposes at about 650 °C. The deep-ultraviolet (DUV) transmittance spectrum reveals that its UV cutoff wavelength is down to ∼150 nm. Theoretical calculations show that BBF has a large birefringence (Δn = 0.13 at 200 nm), which mainly originates from the infinite planar [Be2BO3F2]∞ layers. In conclusion, BBF may be served as a potential DUV birefringent material.

Au Nanoparticles Decorated TiO2 Nanotube Arrays as a Recyclable Sensor for Photoenhanced Electrochemical Detection of Bisphenol A

A photorefreshable and photoenhanced electrochemical sensing platform for bisphenol A (BPA) detection based on Au nanoparticles (NPs) decorated carbon doped TiO2 nanotube arrays (TiO2/Au NTAs) is described. The TiO2/Au NTAs were prepared by quick annealing of anodized nanotubes in argon, followed by controllable electrodeposition of Au NPs. The decoration of Au NPs not only improved photoelectrochemical behavior but also enhanced electrocatalytic activities of the resulted hybrid NTAs. Meanwhile, the high photocatalytic activity of the NTAs allowed the electrode to be readily renewed without damaging the microstructures and surface states after a short UV treatment. The electrochemical detection of BPA on TiO2/Au NTAs electrode was significantly improved under UV irradiation as the electrode could provide fresh reaction surface continuously and the further increased photocurrent resulting from the improved separation efficiency of the photogenerated electron-hole pairs derived from the consumption of holes by BPA. The results showed that the refreshable TiO2/Au NTAs electrode is a promising sensor for long-term BPA monitoring with the detection limit (S/N = 3) of 6.2 nM and the sensitivity of 2.8 μA·μM(-1)·cm(-2).

Fabrication of protein microarrays for alpha fetoprotein detection by using a rapid photo-immobilization process

In this study, protein microarrays based on sandwich immunoassays are generated to quantify the amount of alpha fetoprotein (AFP) in blood serum. For chip generation a mixture of capture antibody and a photoactive copolymer consisting of N,N-dimethylacrylamide (DMAA), methacryloyloxy benzophenone (MaBP), and Na-4-styrenesulfonate (SSNa) was spotted onto unmodified polymethyl methacrylate (PMMA) substrates. Subsequently to printing of the microarray, the polymer and protein were photochemically cross-linked and the forming, biofunctionalized hydrogels simultaneously bound to the chip surface by short UV- irradiation. The obtained biochip was incubated with AFP antigen, followed by biotinylated AFP antibody and streptavidin-Cy5 and the fluorescence signal read-out. The developed microarray biochip covers the range of AFP in serum samples such as maternal serum in the range of 5 and 100ng/ml. The chip production process is based on a fast and simple immobilization process, which can be applied to conventional plastic surfaces. Therefore, this protein microarray production process is a promising method to fabricate biochips for AFP screening processes.

PRELIMINARY PHARMACOGNOSTICAL AND PHYTOCHEMICAL EVALUATION OF AROGYAVARDHINI COMPOUND- AN EMERGING FORMULATED MEDICINE FOR METABOLIC SYNDROME

Context: Arogyavardhini Compound is an emerging formulated herbo-mineral formulation for treatment of metabolic syndrome. Metabolic syndrome is group of risk factors like, increased waist circumference, insulin resistance, increased triglycerides, decreased high density lipoproteins and hypertension for coronary artery diseases and type 2 diabetes mellitus. Arogyavardhini compound consist equal quantity of Arogyavardhini Rasa and single bulb garlic powder. Arigyavardhini Rasa having proven anti dyslipidemiac and weight reducing effect and Garlic having antidiabetic, antidyslipidemic, antihypertensive effect, the combination called Arogyavardhini Compound has been formulated for management of metabolic syndrome. Aim : Authentication of raw drug of Arogyavardhini Compound and phytochemical evaluation of finished product. Materials and methods: Arogyavardhini Compound was evaluated on the basis of powder microscopy and analytical parameters like pH, Ash value, acid insoluble ash, water soluble extract, methanol extract and high performance thin layer chromatography . Results: Powder microscopy revealed the presence of Annular vessels of Musta , Starch grains of Vacha, Stone cells of Pippali , Stone cells of Chitraka, Oleoresins of Shunthi, etc. Physicochemical parameters such as total Ash value (15.91%), water soluble extract (13.5%), methanol soluble extract (17.2%) were assessed in preliminary physicochemical scanning. HPTLC revealed maximum 09 spots in short wave UV 254 nm. and 07 spots were obtained in long wave UV 366 nm. Conclusion: Pharmacognostical study revealed genuinity of raw drugs. Physico-chemical and HPTLC studies inferred that the formulation meets the minimum quality standards as reported in the API at a preliminary level. The inference from this study may be used as reference standard in the further quality control researches. KEY WORDS : Arogyavardhini Compound, HPTLC, Pharmacognosy , Physicochemical analysis .

UV-Vis Photocurrent in SiOx Films with Silicon Nanocrystals Obtained by HFCVD

Actually, optical and electrical characteristics of the SiOx films need to be understood in order to improve and propose optoelectronics devices. Non-stoichiometric silicon oxide (SiOx) films with embedded silicon nanocrystals (Si-ncs) were obtained by hot filament chemical vapor deposition (HFCVD) technique. The authors report high photocurrent of two-terminal metal-oxide-semiconductor (MOS)-like where light is absorbed in the SiOx films with Si-ncs on n–type silicon substrates. Operated at both bias (reverse and direct), where enhanced photocurrent and increased when applied white light, short UV and large UV were observed. The optical properties as photoluminescence and absorption spectra were obtained. Current-Voltage (I–V) measurements in dark and under illumination conditions were realized. The Si-ncs and defects in the SiOx films should have an important role in the high photocurrent. We assume that a high response of the SiOx/Si junction is achieved probably due to a combined effect of the optical down conversion and photo excited electrons in the SiOx films.

Dynamically stiffening hydrogels differentially modulates malignant transformation of mammary epithelial cells

Event Abstract Back to Event Dynamically stiffening hydrogels differentially modulates malignant transformation of mammary epithelial cells Matthew G. Ondeck1, Laurent Fattet2, 3, Spencer Wei2, 3, Jing Yang2, 3 and Adam J. Engler1, 4, 5 1 UC San Diego, Material Science, United States 2 UC San Diego, Moores Cancer Center, United States 3 UC San Diego, Pharmacology, United States 4 UC San Diego, Bioengineering, United States 5 Sanford Consortium for Regenerative Medicine, United States Mammary epithelial cells, e.g. MCF10A, are known to respond to differences in ECM stiffness and undergo epithelial-mesenchymal transition (EMT) on stiffer ECM lacking. While this is akin to the stiff mammary tumors that a woman can detect with manual palpation, breast cancer fibrosis is a dynamic process that results in matrix stiffening from soft (150 Pascal; Pa) to stiff (3000 Pa) over months to years as a result of enhanced collagen expression and lysyloxidase crosslinking. To more accurately mimic the onset of tumor-associated fibrosis, MCF10A mammary epithelial cells were cultured on top of dynamic methacrylated-hyaluronic acid (MeHA) hydrogels, whose stiffness that can be modulated by a two-step polymerization process, and within a matrigel layer. To more appropriately mimic temporal stiffening that occurs in vivo, the photopolymerization step is repeated using a short UV exposure to create stiffen the matrix after MCF10A cells have formed acini; short exposure creates negligible DNA damage or other negative effects on MCF10A cells. Acini remain polarized until the matrix is stiffened at which point some appear to undergo EMT based on morphological assessment. However, the degree of matrix stiffening and culture time prior to stiffening plays a large role in acini transformation; delayed onset of matrix stiffening from 6 to 10 days prevented malignant transformation in 35% of acini while acini were not responsive to stiffening below 1000 Pa. To ensure that early stiffening was not density dependent, acini of differing cell density were transplanted onto stiffening MeHA hydrogels where we found that transformation was independent of acinus size and cell density. Moreover EMT was not cell intrinsic as sequential rounds of stiffening did not permanently induce a specific phenotype, e.g. stiffness-induced EMT cells could revert to acinar cells and vice versa. Of those cells that lost polarity during dynamic stiffening, a subset maintained epithelial markers and failed to show nuclear localized Twist1, an EMT marker, which together suggest that stiffness exhibits transient epigenetic regulation on mammary epithelial cell state during malignant transformation. Keywords: Biomimetic, cell phenotype, 3D scaffold, mechanical property Conference: 10th World Biomaterials Congress, Montréal, Canada, 17 May - 22 May, 2016. Presentation Type: New Frontier Oral Topic: Biomaterials for mechanical interfaces Citation: Ondeck MG, Fattet L, Wei S, Yang J and Engler AJ (2016). Dynamically stiffening hydrogels differentially modulates malignant transformation of mammary epithelial cells. Front. Bioeng. Biotechnol. Conference Abstract: 10th World Biomaterials Congress. doi: 10.3389/conf.FBIOE.2016.01.00438 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 27 Mar 2016; Published Online: 30 Mar 2016. Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Matthew G Ondeck Laurent Fattet Spencer Wei Jing Yang Adam J Engler Google Matthew G Ondeck Laurent Fattet Spencer Wei Jing Yang Adam J Engler Google Scholar Matthew G Ondeck Laurent Fattet Spencer Wei Jing Yang Adam J Engler PubMed Matthew G Ondeck Laurent Fattet Spencer Wei Jing Yang Adam J Engler Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Photodegradation of organic dyes based on anatase and rutile TiO2nanoparticles

Dye degradation study using anatase and rutile titania suggests maximum efficiency of about 88% using anatase phase for MB under short UV light however, the maximum degradation under long UV light was not more than 65% (anatase/ rutile/EBT).

A preliminary phyto-pharmacognostical evaluation of Opuntia elatior Mill. (Nagaphani or Hathalo-thore) fruit

In Gujarat, Opuntia elatior Mill., a member of Cactaceae family known as Nagaphani or Hathlo-thore has been reported for its traditional uses as a medicinal plant. It is used as remedy in different disease conditions like anaemia, asthma etc. by tribal of Gujarat state. A detailed pharmacognostical character and pharmaceutical analysis of its fruit is not reported still yet. An attempt has been made to study the macroscopic, microscopic, physicochemical parameters and HPTLC profile of its fruit following standard procedures. Results show in Transverse section of unripe fruit, presence of outer exocarp layer with rosette crystals, followed by mesocarp and inner endocarp. Transverse section of ripen fruits, shows presence of same characters as fresh unripe fruit except the presence of betacyanins in its mesocarp layer. Powder microscopy of mature fruit shows diagnostic characters like multicellular tri chomes, rosette crystals of calcium oxalate, coloring matter and starch grains. The ash value of O. elatior fruit   is 3.59 % w/w, pH - 5.27, total solid content - 10.83 %, viscosity - 5.11 and Specific gravity is 1.042. HPTLC study showed the presence of four and two spots in short and long UV respectively, among them, 0.04 and 0.97 are the common Rf value. These observed pharmacognostical, physicochemical parameters and HPTLC profile may be useful to establish the botanical standards for identification and standardization of O. elatior fruit

Reversibly Switching Bilayer Permeability and Release Modules of Photochromic Polymersomes Stabilized by Cooperative Noncovalent Interactions.

We report on the fabrication of photochromic polymersomes exhibiting photoswitchable and reversible bilayer permeability from newly designed poly(ethylene oxide)-b-PSPA (PEO-b-PSPA) diblock copolymers, where SPA is spiropyran (SP)-based monomer containing a unique carbamate linkage. Upon self-assembling into polymersomes, SP moieties within vesicle bilayers undergo reversible phototriggered isomerization between hydrophobic spiropyran (SP, λ2 > 450 nm irradiation) and zwitterionic merocyanine (MC, λ1 < 420 nm irradiation) states. For both SP and MC polymersomes, their microstructures are stabilized by multiple cooperative noncovalent interactions including hydrophobic, hydrogen bonding, π-π stacking, and paired electrostatic (zwitterionic) interactions, with the latter two types being exclusive for MC polymersomes. Control experiments using analogous block copolymers of hydrophobic SP monomer with a carbonate linkage (SPO) and conventional spiropyran methacrylate monomer (SPMA) containing a single ester functionality were then conducted, revealing that carbamate-incurred hydrogen bonding interactions in PEO-b-PSPA are crucial for polymersome stabilization in the zwitterionic MC state. Moreover, reversible phototriggered SP-to-MC polymersome transition is accompanied by membrane polarity and permeability switching from being nonimpermeable to selectively permeable toward noncharged, charged, and zwitterionic small molecule species below critical molar masses. Intriguingly, UV-actuated MC polymersomes possess two types of release modules: (1) sustained release upon short UV irradiation duration by taking advantage of the unexpectedly slow spontaneous MC-to-SP transition kinetics (t1/2 > 20 h) under dark conditions; (2) on-demand and switchable release under alternated UV-vis light irradiation. We further demonstrate photoswitchable spatiotemporal release of 4',6-diamidino-2-phenylindole (DAPI, cell nuclei-staining dye) within living HeLa cells.

Characterization of polarizer made of the deep-UV birefringent crystal Ba2Mg(B3O6)2.

In optical communications and the laser industry, modulating the polarization of light requires crystals with both large birefringence and a wide transparent range. A good candidate for a deep-UV birefringent crystal is Ba2Mg(B3O6) because it has a large birefringence and short UV cutoff edge. We grew Ba2Mg(B3O6)2 crystals with sizes up to 41 mm×40 mm×7 mm using the top-seeded solution growth method. We obtained the thermal-expansion coefficients in different directions and the thermo-optic coefficients and then designed and manufactured a Glan-Taylor type polarizer to fulfill the commercial requirements.

La-doped ZnO nanoflower as photocatalyst for methylene blue dye degradation under UV irradiation

Lanthanum doped ZnO flower-like structured nanoparticles were synthesized through microwave assisted sol–gel technique. X-ray diffraction, scanning electron microscopy, transmission electron microscopy analysis confirmed the size, structural morphology and successful compound formation of the samples. The band gap was calculated from Tauc’s plot using UV–Vis spectroscopy data. Lanthanum doped ZnO nanoparticles were used for the photocatalytic degradation of methylene blue dye under UV light irradiation. Compared to pure ZnO sample, La-doped samples exhibited higher photocatalytic dye degradation under UV light irradiation with short time duration. Among the different amounts of dopant, 3 mol% La-doped ZnO nano rods showed the highest degradation with short time UV light irradiation (60 min). Other factors such as particle size, morphology and defects also affect the photocatalytic activity. In our study, the main factor that influence photocatalytic activity is the separation of photo induced electron–hole pair due to defects formation in the sample. The 3 mol% sample has the appropriate electron–hole separation due to defects compared to pure ZnO. The influence of defects on the photocatalytic activity of all samples has been revealed using photoluminescence spectroscopy analysis. Furthermore, the effect of various operational parameters such as photocatalyst quantity, dye concentration and dopant concentrations were also optimized.

Ultrafast photoelectron spectroscopy of solutions: space-charge effect

The method of time-resolved XUV photoelectron spectroscopy is applied in a pump–probe experiment on a liquid micro-jet. We investigate how the XUV energy spectra of photoelectrons are influenced by the space charge created due to ionization of the liquid medium by the pump laser pulse. XUV light from high-order harmonic generation is used to probe the electron population of the valence shell of iron hexacyanide in water. By exposing the sample to a short UV pump pulse of 266 nm wavelength and ∼55 fs duration, we observe an energy shift of the spectral component associated with XUV ionization from the Fe 3d(t2g) orbital as well as a shift of the water spectrum. Depending on the sequence of the pump and probe pulses, the arising energy shift of photoelectrons acquires a positive or negative value. It exhibits a sharp positive peak at small time delays, which facilitates to determine the temporal overlap between pump and probe pulses. The negative spectral shift is due to positive charge accumulated in the liquid medium during ionization. Its dissipation is found to occur on a (sub)nanosecond time scale and has a biexponential character. A simple mean-field model is provided to interpret the observations. A comparison between the intensity dependencies of the spectral shift and the UV ionization yield shows that the space-charge effect can be significantly reduced when the pump intensity is attenuated below the saturation level of water ionization. For the given experimental conditions, the saturation intensity lies at W cm−2.

RbMgCO₃F: A New Beryllium-Free Deep-Ultraviolet Nonlinear Optical Material.

A new deep-ultraviolet nonlinear optical material, RbMgCO3F, has been synthesized and characterized. The achiral nonpolar acentric material is second harmonic generation (SHG) active at both 1064 and 532 nm, with efficiencies of 160 × α-SiO2 and 0.6 × β-BaB2O4, respectively, and exhibits a short UV cutoff, below 190 nm. RbMgCO3F possesses a three-dimensional structure of corner-shared Mg(CO3)2F2 polyhedra. Unlike other acentric carbonate fluorides, in this example, the inclusion of Mg(2+) creates pentagonal channels where the Rb(+) resides. Our electronic structure calculations reveal that the denticity of the carbonate linkage, monodentate or bidendate, to the divalent cation is a useful parameter for tuning the transparency window and achieving the sizable SHG response.

Large increase in the electron capture and excitation cross sections for Li+ colliding with atomic H under UV laser assistance

Neutralization and ash products due to electron capture processes in plasmas reduce the efficiency of energy generation in fusion Tokamak reactors. Therefore, lithium ions have been used to improve the efficiency of energy generation where good control of the electron capture process is required. Here, we show that an intense ( W cm−2), ultra-short (1 fs at full width half-maximum) Gaussian laser pulse in the UV region can enhance the electron capture process on in the low collision keV energy region. We find a factor of 10 enhancement in electron capture cross-section at impact energies lower than 10 keV amu−1 for an 80 nm wavelength laser and a factor of 2 for the excitation process in the hydrogen atom as compared to the laser-free case. In contrast, for a 200 nm wavelength laser the increase of the electron capture cross-sections takes place around 1 keV amu−1 by a factor of 3 and no enhancement for the excitation process. Our results show that the UV assisted production of Li can be controlled, particularly for short UV wave-length for a specific collision energy range. We anticipate that our findings will facilitate UV laser control of the Li production in Tokamak reactors and encourage further experimental work in this system.

Effect of Bifidobacterium breve B-3 on skin photoaging induced by chronic UV irradiation in mice.

Probiotics have been shown to have a preventative effect on skin photoaging induced by short term UV irradiation, however, the underlying mechanisms and the effect of probiotics on skin photoaging induced by chronic UV irradiation remain unclear. In this study, we investigated the effect of Bifidobacterium breve B-3 on skin photoaging induced by chronic UV irradiation in hairless mice. Mice were irradiated with UVB three times weekly and orally administered B. breve B-3 (2×10(9) cfu/mouse /day) for 7 weeks. Nonirradiated mice and UVB-irradiated mice without probiotic treatment were used as controls. B. breve B-3 significantly suppressed the changes of transepidermal water loss, skin hydration, epidermal thickening and attenuated the damage to the tight junction structure and basement membrane induced by chronic UVB irradiation. Administration of B. breve B-3 tended to suppress the UV-induced interleukin-1β production in skin (P=0.09). These results suggest that B. breve B-3 could potentially be used to prevent photoaging induced by chronic UV irradiation.

Passivation of Metal Oxide Surfaces for High-Performance Organic and Hybrid Optoelectronic Devices

The exciton quenching properties of solution-processed nickel oxide (NiOx) and vanadium oxide (VOx) are studied by measuring the photoluminescence (PL) of a thin emitting layer (EML) deposited on top of the metal oxides. Strong exciton quenching is evidenced at the metal oxide/EML interface, which is proved to be detrimental to the performance of optoelectronic devices. With a thin polyvinylpyrrolidone (PVP) passivation polymer adsorbed on top of metal oxides, the PL quenching is found to be effectively suppressed. A short UV–O3 treatment on top of the PVP-passivated metal oxides turns out to be a key procedure to trigger the chemical binding between the PVP passivation polymer and the metal oxide surface species, which turns out to be necessary for efficient hole injection and extraction for organic light emitting diodes (OLEDs) and solar cell devices, respectively. With the PVP passivation layer followed by UV–O3 treatment, the OLEDs incorporating NiOx as a hole transport layer (HTL) shows a record curr...

Unique Curing Properties through Living Polymerization in Crosslinking Materials: Polyurethane Photopolymers from Vinyl Ether Building Blocks.

Photopolymers with unique curing capabilities were produced by combining living cationic polymerization with network formation and restricted polymer motion. A vinyl ether diol was synthesized as a functional building block and reacted with isophorone diisocyanate to form a highly functionalized vinyl ether polyurethane as a model system with high crosslinking ability. When using a cationic photoinitiator, fast polymerization is observed upon short UV irradiation. Curing proceeds in the absence of light and under ambient conditions without oxygen inhibition. Cationic active sites become trapped dormant species upon network-induced vitrification and surprisingly remain living for several days. The polymerization can be reactivated by additional UV irradiation and/or raised temperature. The curing behavior was studied in detail by using UV and FT-NIR coupled rheology and photo-DSC to simultaneously study spectroscopic and mechanical information, as well as thermal effects.

Synthesis, characterisation, and study of the photophysical properties of highly stable imidazole‐based novel solid‐state fluorescent azo colourants

Novel solid‐state fluorescent azo colourants derived from 5‐amino‐2‐(4‐dimethylaminophenyl) benzimidazole as electron donor were synthesised. The colourants were characterised by means of elemental analysis, 1H NMR, and mass spectrometry. These colourants showed molar extinction coefficients in the range 12 000–48 000 dm3 mol−1 cm−1. These compounds exhibited solid‐state fluorescence under short UV (254 nm). Electron coupling originating from broad π‐electron delocalisation and keto–enol form is responsible for the large Stokes shift as indicated by absorption and fluorescence spectra. These colourants were soluble in polar aprotic high‐boiling solvents such as N,N‐dimethylformamide, N,N‐dimethylacetamide, and dimethyl sulphoxide, whereas they were insoluble in other common organic solvents. Thermogravimetric analysis of solid‐state fluorescent colourants showed that two of the colourants showed thermal stability in the range 230–240 °C, whereas for the rest of the colourants it was found to be lower, and hence the two colourants could find application in the coloration of polymers.

Simulated pressure-induced blue-shift of phase-matching region and nonlinear optical mechanism for K3B6O10X (X = Cl, Br)

Birefringence plays a great role in phase matching of the nonlinear optical (NLO) crystals. Small birefringence restricts various crystals from achieving deep-ultraviolet laser output although they exhibit short UV cutoff edges and high second-harmonic generation (SHG) intensities. An access to achieve deeper coherent light output through external pressure on NLO crystal, K3B6O10Cl is proposed and demonstrated through computer experiment based on the first principles theory. The “hot spot” in structure that determine the SHG effects and birefringence were highlighted. The shortest achievable phase-matching wavelengths are predicted based on calculated refractive indices. It is found that the quasi-planar (B6O10)2− group is the dominant contributing unit to optical anisotropy. The pressure-induced increase of polarizability anisotropy of (B6O10)2− group can notably enlarge birefringence which extends the shortest achievable wavelength of K3B6O10Cl frequency conversion. The results show that pressure engineering may be a promising scheme to overcome the drawback of small birefringence of some NLO crystals.