| 1. |
- Baev, Alexander, et al.
(författare)
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Metaphotonics : An emerging field with opportunities and challenges
- 2015
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Ingår i: Physics reports. - : Elsevier. - 0370-1573 .- 1873-6270. ; 594, s. 1-60
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Forskningsöversikt (refereegranskat)abstract
- Metaphotonics is an emerging multidisciplinary field that deals with manipulation of electro-magnetic fields in nanoengineered (meta)materials using both electric and magnetic interactions and their cross-coupling. It offers unprecedented control of both linear and nonlinear optical functions for applications ranging from optical switching, to negative- and near-zero refractive index metamaterials, to chiral bioimaging, to cloaking. However, realization of such applications requires physics-guided nanoengineering of appropriate artificial media with electro-magnetic properties at visible and infrared wavelengths that are tailored to surpass those of any naturally-occurring material. Here, we review metaphotonics with a broadened vision and scope, introduce potential applications, describe the role of theoretical physics through multiscale modeling, review the materials development and current status, and outline opportunities in this fertile emerging field.
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| 2. |
- Deska, Radoslaw, et al.
(författare)
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Two-photon excited luminescence and second-harmonic generation in quinacridone microstructures
- 2020
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Ingår i: Dyes and pigments. - : ELSEVIER SCI LTD. - 0143-7208 .- 1873-3743. ; 177
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Tidskriftsartikel (refereegranskat)abstract
- Nonlinear optical microscopy was employed to investigate the properties of microstructures of quinacridone, a hydrogen-bonded pigment, derivative of quinacridine. Recently, quinacridone hierarchical microstructures (mu-QNC) having different nature-inspired morphologies were reported, e.g. in the shape of hedgehogs formed by self-assembled nano-needles. We find that such microcrystals have structure-dependent linear optical properties and exhibit strong two-photon excited fluorescence when irradiated with a near-infrared femtosecond laser. mu-QNCs exhibit different nonlinear optical properties for different crystal structures, including the emergence of symmetry-forbidden second-harmonic generation.
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| 3. |
- Hanczyc, Piotr, 1985, et al.
(författare)
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Two-photon absorption of metal–organic DNA-probes
- 2012
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Ingår i: Dalton Transactions. - : Royal Society of Chemistry (RSC). - 1477-9226 .- 1477-9234. ; 41:11, s. 3123-3125
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Tidskriftsartikel (refereegranskat)abstract
- We report remarkable multiphoton absorption properties of DNA intercalating ruthenium complexes: (1) [Ru(phen)2dppz]2+; (2) [(11,11′-bidppz)(phen)4Ru2]4+; (3) [11,11′-bipb(phen)4Ru2]4+. Two-photon spectra in the range from 460 to 1100 nm were measured using the Z-scan technique. In particular, complex 2 was found to exhibit very strong two- and three-photon absorption properties, which could be an effect of symmetric charge transfer from the ends towards the middle of the conjugated dimeric orbital system. We propose that these molecules could provide a new generation of DNA binding nonlinear chromophores for wide applications in biology and material science. The combination of a large two-photon cross section and strong luminescence quantum yields for the molecules when intercalated makes the compounds uniquely bright and photo-stable probes for two-photon luminescence imaging and also promising as enhanced photosensitizers in two-photon sensitizing applications.
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| 4. |
- Hanczyc, Piotr, 1985, et al.
(författare)
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Two-photon absorption of polyfluorene aggregates stabilized by insulin amyloid fibrils
- 2015
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Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 5:61, s. 49363-49368
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Tidskriftsartikel (refereegranskat)abstract
- We report on the photophysical and optical properties of a polyfluorene derivative (PFO) and its binding to the amyloid-forming protein insulin. The complexation is based on weak supramolecular interactions between amyloid fibrils and PFO in dissolved and aggregated forms. In particular, complexes of polyfluorene aggregates display sizeable two-photon absorption when stabilized by insulin fibril nanotemplates. We propose that a two-photon absorption enhancement mechanism is related to the combination of through-bond and through-space interactions of PFO. The findings reported here suggest that polyfluorene aggregates offer good nonlinear absorption properties and can be used as molecular markers for amyloid fibril recognition.
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| 5. |
- He, Guang S., et al.
(författare)
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Twisted pi-System Chromophores for All-Optical Switching
- 2011
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 133:17, s. 6675-6680
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Tidskriftsartikel (refereegranskat)abstract
- Molecular chromophores with twisted pi-electron systems have been shown to possess unprecedented values of the quadratic hyperpolarizability, beta, with very large real parts and much smaller imaginary parts. We report here an experimental and theoretical study which shows that these twisted chromophores also possess very large values of the real part of the cubic hyperpolarizability, gamma, which is responsible for nonlinear refraction. Thus, for the two-ring twisted chromophore TMC-2 at 775 nm, relatively close to one-photon resonance, n(2) extrapolated to neat substance is large and positive (1.87 x 10(-13) cm(2)/W), leading to self-focusing. Furthermore, the third-order response includes a remarkably low two-photon absorption coefficient, which means minimal nonlinear optical losses: the T factor, alpha(2)lambda/n(2), is 0.308. These characteristics are attributed to closely spaced singlet biradical and zwitterionic states and offer promise for applications in all-optical switching.
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| 6. |
- Matczyszyn, Katarzyna, et al.
(författare)
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One- and Two-Photon Absorption of a Spiropyran-Merocyanine System : Experimental and Theoretical Studies
- 2015
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Ingår i: Journal of Physical Chemistry B. - : American Chemical Society (ACS). - 1520-6106 .- 1520-5207. ; 119:4, s. 1515-1522
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Tidskriftsartikel (refereegranskat)abstract
- We report on the nonlinear optical properties measurements and quantum-chemical calculations of a well-known photochromic system consisting of spiropyran and the merocyanine photoproduct. The study of nonlinear absorption and refraction properties of the molecules dissolved in chloroform were performed with the Z-scan technique, using femtosecond pulses in a wide range of wavelengths. Maxima in the two-photon absorption spectrum at 700 and 1050 nm were found for the merocyanine form, and the corresponding two-photon absorption cross section is 80 GM and 20 GM, respectively. The latter feature does not vanish completely in the nonlinear spectrum of the spiropyran form, possibly because of the existence of some photoconversion caused by the laser beam during the measurements. A nonlinear absorption peak at 900 nm is found in the spiropyran form with an effective cross section of about 20 GM; it is likely due to three-photon absorption or to absorption by some intermediate species. The experimental data are supported by calculations performed with the use of a hybrid quantum mechanics-molecular mechanics approach.
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| 7. |
- Olesiak-Banska, J., et al.
(författare)
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Nonlinear absorption spectra of ethidium and ethidium homodimer
- 2012
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Ingår i: Chemical Physics. - : Elsevier BV. - 0301-0104. ; 404, s. 33-35
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Tidskriftsartikel (refereegranskat)abstract
- The Z-scan technique was used to determine the spectral dependence of the nonlinear absorption in well-known DNA intercalators: ethidium bromide and its homodimer. It is found that the compounds show essentially the same features of their nonlinear absorption spectra with the magnitudes of the relevant cross sections scaling with molecular weight of chromophore compound.
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| 8. |
- Olesiak-Banska, Joanna, et al.
(författare)
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Revealing Spectral Features in Two-Photon Absorption Spectrum of Hoechst 33342 : A Combined Experimental and Quantum-Chemical Study
- 2013
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Ingår i: Journal of Physical Chemistry B. - : American Chemical Society (ACS). - 1520-6106 .- 1520-5207. ; 117:40, s. 12013-12019
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Tidskriftsartikel (refereegranskat)abstract
- We present the results of wide spectral range Z-scan measurements of the two-photon absorption (2PA) spectrum of the Hoechst 33342 dye. The strongest 2PA of the dye in aqueous solution is found at 575 nm, and the associated two-photon absorption cross section is 245 GM. A weak but clearly visible 2PA band at similar to 850 nm is also observed, a feature that could not be anticipated from the one-photon absorption spectrum. On the basis of the results of hybrid quantum mechanics/molecular mechanics calculations, we put forward a notion that the long-wavelength feature observed in the two-photon absorption spectrum of Hoechst 33342 is due to the formation of dye aggregates.
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| 9. |
- Samoc, Marek, et al.
(författare)
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Cubic Nonlinear Optical Properties of Platinum-Terminated Polyynediyl Chains
- 2008
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Ingår i: Inorganic Chemistry. - : American Chemical Society (ACS). - 0020-1669 .- 1520-510X. ; 47:21, s. 9946-9957
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Tidskriftsartikel (refereegranskat)abstract
- The wavelength dependence of the cubic nonlinearity of ligated platinum-terminated polyynes trans, trans-{(P-MeC6H4)(3)P}(2)(p-MeC6H4)Pt(C C)(n)Pt(p-C6H4Me){P(p-C6H4Me)(3)}(2) (n = 3-6, 8, 10, 12) has been examined by femtosecond Z-scan studies in the wavelength range 520-1500 nm and the results rationalized by density functional theory calculations on the model complexes trans, trans-(H3P)(2)(C6H5)Pt(C C)(n)Pt(C6H5)(PH3)(2) (n = 2-8, 10, 12). Although the final states for one- and two-photon transitions are not the same in these centrosymmetric molecules, the Z-scan studies reveal coincidences in one-photon absorption with features in the frequency dependencies of both real and imaginary parts of the cubic hyperpolarizability, as well as inflections in the frequency dependencies of the real part of gamma that correspond to resonances in the imaginary part of gamma. The theoretical studies suggest that the linear absorption spectra are dominated by (XAg)-Ag-1 -> n(1)B(3u) transitions, with the first state of B-3u symmetry playing a steadily diminishing role upon oligoyne chain lengthening. The theoretical studies also predict a red-shift of two-photon absorption (TPA) profile with increasing conjugation length, and a significant enhancement on proceeding from the shortest to the longest chromophore, trends that are observed experimentally. The experimental low-energy TPA maxima for these complexes can be approximated by a simple Gaussian profile. The sp-carbon chain-length dependence of linear and nonlinear absorption maxima enable an estimate (neglecting saturation) of 660 and 1000 nm for the infinite carbon chain, carbyne.
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| 10. |
- Samoc, Marek, et al.
(författare)
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Nonlinear absorption and nonlinear refraction: Maximizing the merit factors
- 2012
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Ingår i: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE. - 0277-786X .- 1996-756X. - 9780819489012 ; 8258, s. Art. no. 82580V-
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Konferensbidrag (refereegranskat)abstract
- Both nonlinear absorption and nonlinear refraction are effects that are potentially useful for a plethora of applications in photonics, nanophotonics and biophotonics. Despite substantial attention given to these phenomena by researchers studying the merits of disparate systems such as organic materials, hybrid materials, metal-containing molecules and nanostructures, it is virtually impossible to compare the results obtained on different materials when varying parameters of the light beams and different techniques are employed. We have attempted to address the problem by studying the properties of various systems in a systematic way, within a wide range of wavelengths, and including the regions of onephoton, two-photon and three-photon absorption. The objects of our studies have been typical nonlinear chromophores, such as π-conjugated molecules, oligomers and polymers, organometallics and coordination complexes containing transition metals, organometallic dendrimers, small metal-containing clusters, and nanoparticles of various kinds, including semiconductor quantum dots, plasmonic particles and rare-earth doped nanocrystals. We discuss herein procedures to quantify the nonlinear response of all of these systems, by defining and comparing the merit factors relevant for various applications.
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