The use of commercial long-wavelength (>650 nm) laser dyes in many biophotonic applications has several important limitations, including low absorption at the standard pump wavelength (532 nm) and ...poor photostability. Here, we demonstrate that the use of Förster type (FRET) energy transfer can overcome these problems to enable efficient, stable near-infrared lasing in a colloidal suspension of latex nanoparticles containing a mixture of Rhodamine 6G and Nile Blue dyes. Experimental and theoretical analyses of the photophysics suggest that the dominant energy transfer mechanism is Förster type via dipole-dipole coupling, and also reveal an unexpected core/shell morphology in the dye-doped nanoparticles. FRET-assisted incoherent random lasing is also demonstrated in solid samples obtained by evaporation of colloidal suspensions.
A series of mono‐ to hexachlorinated BODIPY dyes have been prepared in good to excellent yields through the use of N‐chlorosuccinimide as an inexpensive halogenating reagent. This library of ...chlorinated dyes allowed analysis in detail, from the experimental and theoretical points of view, of the dependency of the photophysical and optical properties of the dyes on the number and positions of the chlorine substituents on their BODIPY cores. Quantum mechanical calculations predict the regioselectivity of the halogenation reaction and explain why some positions are less prone to chlorination. The new chlorinated BODIPYs exhibit enhanced laser action with respect to their non‐halogenated analogues, both in liquid solution and in the solid phase. In addition, chlorination is a facile and essentially costless protocol for overcoming important shortcomings exhibited by commercially available BODIPYs, which should favor their practical applications in optical and sensing fields.
Chlorination is a direct and low‐cost strategy allowing significant enhancement of the optical properties of BODIPY dyes, overcoming some of their most important shortcomings for laser applications such as low absorptions at standard laser pumping wavelengths and/or low photostabilities.
Efficient random lasing (RL) from self‐assembled dye‐doped latex nanoparticles (d = 50–380 nm) presenting size polydispersity is reported. This new system exhibits a very good chemical compatibility ...between dye (Rhodamine 6G) and polymer as well as a high refractive index contrast between nanoparticle and surroundings (air), in such a way that its emission properties surpass the ones previously reported in similar systems. Furthermore, this system allows analyzing in detail the effects of the nanoparticle size polydispersity and the packing density on the RL emission properties. It is shown that size polydispersity gives rise to non‐uniformities in the filling fraction along the sample that lead to fluctuations on the scattering length across the sample and thus to a variation on the emission properties. Finally, it is observed that the increase of the filling fraction, enabled by the use of binary mixtures of nanoparticles with different sizes, results in remarkable improvements in the RL emission properties.
Efficient random lasing (RL) from self‐assembled dye‐doped latex nanoparticles presenting size polydispersity is reported. Both the nanoparticle size and size polydispersity influence the RL emission properties. The use of binary mixtures of nanoparticles with different sizes improves the RL emission properties with respect to the mixture constituents separately due to an increase in the filling fraction.
A new and facile strategy for the development of photonic materials is presented that fufills the conditions of being efficient, stable, and tunable laser emitters over the visible region of ...spectrum, with the possibility of being easily processable and cost‐effective. This approach uses poly(methyl methacrylate) (PMMA) as a host for new dyes with improved efficiency and photostability synthesized. Using a simple protocol, fluorine atoms in the commercial (4,4‐difluoro‐4‐bora‐3a,4a‐diaza‐s‐indacene) (F‐BODIPY) by carboxylate groups. The new O‐BODIPYs exhibit enhanced optical properties and laser behavior both in the liquid and solid phases compared to their commercial analogues. Lasing efficiencies up to 2.6 times higher than those recorded for the commercial dyes are registered with high photostabilities since the laser output remain at 80% of the initial value after 100 000 pump pulses in the same position of the sample at a repetition rate of 30 Hz; the corresponding commercial dye entirely loses its laser action after only 12 000 pump pulses. Distributed feedback laser emission is demonstrated with organic films incorporating new O‐BODIPYs deposited onto quartz substrates engraved with appropriated periodical structures. These dyes exhibit laser thresholds up to two times lower than those of the corresponding parent dyes with lasing intensities up to one order of magnitude higher.
The development of new O‐BODIPYs, synthesized via the replacement of fluorine atoms by carboxylate groups in commercial (4,4‐difluoro‐4‐bora‐3a,4a‐diaza‐s‐indacene) (F‐BODIPYs), is a successful strategy to obtain optimized laser dyes. Poly(methyl methacrylate) (PMMA) doped with these new derivatives leads to laser materials that are economically affordable and have optimized emission properties in the visible spectral region.
In the search to extend the tuning range of solid‐state dye lasers (SSDLs) to the red‐edge spectral region, new photosensitive materials have been designed and synthesized based on six commercial ...dyes (sulforhodamine B, perylene red, rhodamine 640, LDS698, LDS722, and LDS730) incorporated into different linear, crosslinked, fluorinated, and sililated polymeric matrices. Under transversal pumping at 532 nm, these materials exhibit highly efficient, stable, as well as wavelength‐tunable laser action from the visible‐to‐NIR spectral region (575–750 nm). The lasing performance of the materials doped with perylene and xanthene dyes is, to the best of our knowledge, the highest achieved to date for these chromophores when incorporated into organic, inorganic, or hybrid matrices. Regarding the LDS derivatives, this is the first time that laser action from these dyes in solid‐state media is reported. These particular characteristics have impelled the building of the first prototype SSDL that is compact, versatile, and easy to handle.
New photosensitive materials based on dye‐doped polymeric matrices as active media in a solid‐state dye laser (SSDL) allow a high‐efficiency, stable laser action with finely tunable wavelength to be attained from the visible‐to‐NIR spectral region (575–750 nm). These characteristics have initiated the building of the first SSDL prototype that is compact, hazardless, versatile, and easy to handle (see figure), making it applicable in science and enterprise and attractive for commercial implementation.
A series of meso‐substituted boron‐bipyrromethene (BODIPY) dyes are synthesized and their laser and photophysical properties systematically studied. Laser emission covering a wide visible spectral ...region (from blue to orange) is obtained by just changing the electron donor character of the heteroatom at position 8. The additional presence of methyl groups at positions 3 and 5 results in dyes with a photostability similar to that of the unsubstituted dye but with much improved efficiency. Correlation of the lasing properties of the different dyes to their photophysical properties provides inklings to define synthetic strategies of new BODIPY dyes with enhanced efficiency and modulated wavelength emission over the visible spectral region.
Brighter blue–green dyes: The attachment of heteroatoms at the meso position of boron‐bipyrromethene (BODIPY) dyes modulates the emission region from orange to blue. Further methylation at positions 3 and 5 improves the laser efficiency, thereby maintaining a high photostability. The combination of both effects leads to BODIPYs with improved laser and fluorescence performance in the blue part of the spectrum.
The asymmetrically substituted BODIPY dyes 9a and 9b have been synthesized through a key redox step involving the α-nitroso derivative of the starting pyrrol. Both dyes emit fluorescence with quantum ...yields of ca. 0.7, but only 8b behaves as a good laser dye, with an efficiency of 48% in ethanol solution.
Herein, we report a straight forward stress probing method based on mechanically tunable organic VCSELs via dual detecting-modes. By designing the active layer thickness, uploaded stress was measured ...simultaneously by the laser wavelength and mode separations, facilitating highly sensitive stress detection in broad ranges. Single-mode laser emission with low threshold and narrow line-width was characterized, which could be tuned continuously within 8 nm. The probing sensitivity and resolution were estimated to be 60 Pa and 5.6 nm/KPa respectively, which were ~160-folds higher than previous results.
Here, the design, synthesis, and characterization of laser nanomaterials based on dye‐doped methyl methacrylate (MMA) crosslinked with octa(propyl‐methacrylate) polyhedral oligomeric silsesquioxane ...(8MMAPOSS) is reported in relation to their composition and structure. The influence of the silicon content on the laser action of the dye pyrromethene 567 (PM567) is analyzed in a systematic way by increasing the weight proportion of POSS from 1 to 50%. The influence of the inorganic network structure is studied by replacing the 8MMAPOSS comonomer by both the monofunctionalized heptaisobutyl‐methacryl‐POSS (1MMAPOSS), which defines the nanostructured linear network with the POSS cages appearing as pendant groups of the polymeric chains, and also by a new 8‐hydrogenated POSS incorporated as additive to the polymeric matrices. The new materials exhibit enhanced thermal, optical, and mechanical properties with respect to the pure organic polymers. The organization of the molecular units in these nanomaterials is studied through a structural analysis by solid‐state NMR. The domain size of the dispersed phase assures a homogeneous distribution of POSS into the polymer, thus, a continuous phase corresponding to the organic matrix incorporates these nanometer‐sized POSS crosslinkers at a molecular level, in agreement with the transparency of the samples. The silicon–oxygen core framework has to be covalently bonded into the polymer backbone instead of being a simple additive and both the silica content and crosslinked degree exhibit a critical influence on the laser action.
The fascinating properties of polyhedral oligomeric silsesquioxanes (POSS) impel the synthesis and characterization of new hybrid nanomaterials with advanced optical applications. Here, composition–structure–properties relationships of dye‐doped POSS‐based materials are established and allow the demonstration of solid‐state laser action (see figure) that is not only truly competitive but out‐performs their liquid counterparts.
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