Ivan Biaggio's research while affiliated with Lehigh University and other places

Publications (186)

Article
We introduce electrically poled small molecule assemblies that can serve as the active electro-optic material in nano-scale guided-wave circuits such as those of the silicon photonics platform. These monolithic organic materials can be vacuum-deposited to homogeneously fill nanometer-size integrated-optics structures, and electrically poled at high...
Article
Full-text available
Appropriately designed dual-core fibers using coupling-length phase matching (CLPM) allow for phase-matched frequency downconversion over wide frequency intervals using the third-order optical nonlinearity of glass. By tuning the distance between the two cores, CLPM allows continuously tunable phase matching for widely different wavelengths for the...
Article
Small organic molecules with a π‐conjugated system that consists of only a few double or triple bonds can have significantly smaller optical excitation energies when equipped with donor‐ and acceptor groups, which raises the quantum limits to the molecular polarizabilities. As a consequence, third‐order nonlinear optical polarizabilities become ord...
Article
The geminate annihilation of two triplet excitons created by singlet exciton fission is affected by the dimensionality of transport as determined by typically anisotropic triplet exciton mobilities in organic molecular crystals. We analyze this process using a random-walk model where the time dynamics of the geminate annihilation probability is det...
Conference Paper
Vapor-deposited, monolithic small molecule assemblies deliver a strong, permanent electro- optic response after being electrically poled above the glass transition temperature. They are ideally suited for hybrid electro-optic modulators in integrated silicon photonics.
Conference Paper
We observe singlet exciton fission and the formation of triplet exciton transient gratings that allow us to study the singlet exciton fission time and the rise of the triplet population under different excitation and detection conditions
Conference Paper
Coupling Length Phase Matching (CLPM) enables the generation of mid-infrared radiation using four-wave mixing and the third-order nonlinear optical properties of glass in otherwise unstructured, appropriately designed dual-core optical fibers.
Conference Paper
Focused electro-magnetic radiation concentrates nanoparticles relying only on the magnitude of the optical electric field and ignoring its frequency. This enables broadband optical limiting in the infrared when coupled with a colloidal phase transition.
Conference Paper
Under an applied magnetic field of the order of 0.3 T, singlet exciton fission into two triplet excitons and the subsequent geminate fusion of the latter leads to long-lasting spin entanglement and quantum beats in the emitted fluorescence
Article
By using wavelength-tunable, low fluence picosecond pulses at a 1 kHz repetition rate in a transient grating pump and probe configuration, we show that photoexcitation to higher vibrational levels leads to slower singlet exciton fission rates in rubrene. After the 1 ps photoexcitation, the initial growth of the triplet exciton population is exponen...
Article
We demonstrate wavelength-independent optical limiting based on colloidal phase transitions induced by the dielectrophoretic force from focused electromagnetic radiation. The focused radiation acts as an optical trap that increases the particle density. The increased density then leads to a colloidal gas-solid phase transition and an aggregate that...
Article
Chalcogenide glass – silver heterostructures are candidates for photoresist and diffractive optical applications. To optimize their processing, we report the kinetics of Ag photo-dissolution in As2S3 matrix using in-situ optical transmission/reflection measurements and real time atomic force microscopy (AFM) imaging under optical illumination. The...
Article
Chalcogenide glass-silver heterostructures are candidates for photoresist and diffractive optical applications. To optimize their processing, we report the kinetics of Ag photo-dissolution in As2S3 matrix using in-situ optical transmission/reflection measurements and real time atomic force microscopy (AFM) imaging under optical illumination. The re...
Preprint
Chalcogenide glass-silver heterostructures are candidates for photoresist and diffractive optical applications. To optimize their processing, we report the kinetics of Ag photo-dissolution in As2S3 matrix using in-situ optical transmission/reflection measurements and real time atomic force microscopy (AFM) imaging under optical illumination. The re...
Article
Hydrogen has been found to be an n-type dopant in In2O3 that gives rise to unintentional conductivity. An infrared (IR) absorption line observed at 3306 cm⁻¹ has been assigned to the Hi⁺ center. Two types of experiments have been performed to determine the diffusivity of Hi⁺ in In2O3 from its IR absorption spectra. (i) At temperatures near 700 K, t...
Article
We observe quantum beats in the nanosecond-scale photoluminescence decay of rubrene single crystals after photoexcitation with short laser pulses in a magnetic field in the range of 0.1 to 0.3 T. The relative amplitude of the quantum beats is of the order of 5%. Their frequency is 1.3 GHz when the magnetic field is oriented parallel to the twofold...
Conference Paper
We demonstrate that in-situ poling during organic molecular beam deposition of single-component dense supramolecular assemblies can be used to obtain a preferential molecular order and a bulk linear electro-optic effect in the resulting organic films.
Article
We report on the third-order nonlinear optical properties of a series of molecules, first published in Chem. Eur. J.19, 12693–12704 (2013)CHRYAQ0009-305X10.1002/chem.201301642, where a donor and an acceptor group are separated by a linear conjugated system consisting of only carbon atoms building triple bonds (0 to 5 acetylene spacers). We determin...
Article
Nonlinear optics is the study of all effects that can be described as multi-photon interactions in various material systems, including cases where the frequency of one or more photons tends to zero. This feature issue is dedicated to works on both second-order nonlinear optics (three-photon interactions) and third-order nonlinear optics (four-photo...
Article
We determine both the lifetime and the mobility of photoexcited charge carriers in Sn2P2S6 using holographic time of flight in diffusion mode. From the build-up dynamics of space charge gratings created by pulsed interband illumination at 532 nm, we find a charge carrier lifetime of 2.6 ± 0.5 ns and a charge carrier mobility along the x-axis of 2.4...
Article
We investigate how excitonic processes in rubrene single crystals are affected by a deliberately implanted defect gradient induced by proton irradiation. Spatially resolved measurements show a gradually reduced photoluminescence quantum yield and triplet exciton diffusion length along the defect gradient. Both effects are caused by a decrease in th...
Conference Paper
We report on the exceptionally strong two-photon transition in an optimized family of small donor-acceptor substituted molecules and show how both strength and shape of the two-photon resonance varies with conjugation length.
Article
Transient grating pump and probe experiments are used to investigate excitonic processes on the nanosecond time scale in rubrene single crystals. We find that bimolecular interactions cause a photoinduced excited state density on the order of 0.5 × 1020 cm−3—corresponding to an average distance of ∼3 nm between individual states—to decrease by a fa...
Article
We determine the dispersion of the third-order polarizability of small donor-acceptor substituted organic molecules using wavelength-dependent degenerate four-wave mixing experiments in solutions with varying concentrations. We find that donor-acceptor\char21{}substituted molecules that are characterized by extremely efficient off-resonant nonlinea...
Conference Paper
The two-photon absorption cross section of optimized donor-acceptor substituted small molecules can become extremely large when compared to the size of the molecules and also when compared to the fundamental quantum limit
Conference Paper
We use degenerate four-wave mixing with wavelength-tunable picosecond pulses to study the second hyperpolarizability of molecules in solution. The full dispersion of both real and imaginary parts of the polarizability can be obtained using a semi-automated method
Conference Paper
We show that phase-matching for frequency conversion is possible in a system consisting of two parallel waveguides without any spatial modulation of linear or nonlinear optical properties, both for second and for third-order effects
Conference Paper
The coupling between parallel waveguides leads to a quasi-phase matching effect that allows to obtain phase matching for third-order down conversion and other third-order processes in silica fibers. Several phase matching conditions are found
Article
Understanding behavior of rare-earth ions (REI) in crowded environments is crucial for several nano- and bio-technological applications. Evolution of REI photoluminescence (PL) in small compartments inside a silica hydrogel, mimic to a soft matter bio-environment, has been studied and explained within a solvation model. The model uncovered the orig...
Article
Full-text available
We describe and analyze a quasi-phase-matching scheme for nonlinear optical frequency conversion where the spatial modulation of mode intensity in coupled parallel waveguides provides the required modulation in the generation of the frequency conversion signal, instead of a variation of any material parameter or propagation constant. We analyze thi...
Chapter
This chapter discusses organic molecules for third-order nonlinear optics - responsible for effects such as self- and cross-phase modulation, and all-optical switching - and the issues related to using such molecules to create a solid-state material. The chapter will review the figures of merit that help determine the potential of a small molecule,...
Chapter
This chapter discusses short pulse photoexcitation in organic materials, mostly organic molecular crystals, and the resulting time dynamics of excited states as can be observed by detecting photoluminescence and photoconductivity. The chapter will review the electronic detection of a transient photoconductivity after photoexcitation and the relevan...
Article
Measurements of photoluminescence yield over a wide range of excitation power in rubrene single crystals reveal a transition between a low-yield region and a region with a yield more than an order of magnitude larger. This transition occurs at an excitation density of 3 × 1020 cm-3 absorbed photons per second. This power dependence is predicted in...
Article
We describe noncollinear third-harmonic Maker fringes for the determination of third-order optical nonlinearities. This method builds on the same principles as conventional Maker fringes experiments, but thanks to the limited interaction length of two intersecting beams, it allows to eliminate the requirement of taking into account the contribution...
Conference Paper
We correlate different measurements of photoluminescence, four-wave mixing, and photocurrent with singlet and triplet exciton dynamics in rubrene and discuss implications for organic photovoltaics.
Conference Paper
We report the rise and fall of third-order optical polarizabilities in donor-acceptor substituted molecules featuring a systematically varied conjugation path. We identify the optimum conjugation length that optimizes the non-linear response in small molecules.
Conference Paper
We discuss the use of the phase matching conditions for third-order nonlinear optical frequency conversion to obtain refractive index dispersion over a large spectral range from the visible to the infrared.
Conference Paper
We determine polarization dependent absorption and emission spectra in rubrene and relate them to the molecular properties and crystal structure, identifying the important role played by vibronic induced depolarization in determining the luminescence spectra.
Article
Full-text available
A series of donor-acceptor-substituted alkynes, 2 a-f, was synthesized in which the length of the π-conjugated polyyne spacer between the N,N-diisopropylanilino donor and the 1,1,4,4-tetracyanobuta-1,3-diene (TCBD) acceptor was systematically changed. The effect of this structural change on the optoelectronic properties of the molecules and, ultima...
Conference Paper
The use of non-collinear THG allows to obtain Maker fringes that are not affected by air and allow for a simpler determination of third order susceptibilities.
Article
Transient grating experiments after optical band-gap pulsed illumination of amorphous a-As2Se3 thin films reveal the existence of a well defined transport process occurring on length- and time-scales of the order of micrometers and microseconds, respectively. We tentatively assign this fast process, corresponding to a mobility of 0.04 +/- 0.005 cm(...
Article
Full-text available
We report the intrinsic absorption and photoluminescence spectra of rubrene single crystals, deriving them from a series of experiments performed at different excitation wavelengths and in different experimental geometries. We describe the absorption spectra for all three light polarizations in the crystal, and discuss how anisotropic wavelength-de...
Article
We report the synthesis and physical study of a series of 1,1-dicyano-4-[4-(diethylamino)phenyl]buta-1,3-dienes in which the number and position of additional CN substituents along the 1,1-dicyanobuta-1,3-dienyl fragment is systematically varied. While X-ray analysis provided unambiguous information about molecular geometries in the crystal, UV/Vis...
Article
Full-text available
Silicon represents a mature, affordable platform for fabricating electronic and optical signal processing devices. We discuss all-optical 170 Gbit/s switching, a 42 Gbit/s electro-optic modulator, and proof-of-concept results for a surface plasmon polariton absorption modulator.
Article
We present linear and nonlinear optical properties of small donor-acceptor substituted molecules for third-order nonlinear optics and of their dense assemblies created by molecular beam deposition in high vacuum. The molecules are variations on the DDMEBT molecule, obtained by varying the structure of the electron donating groups around a compact c...
Article
A formal [2 + 2] cycloaddition-cycloreversion (CA-CR) between N,N'-dicyanoquinone diimides (DCNQIs) and electron-rich alkynes was explored, providing a new class of π-conjugated donor-acceptor chromophores. These DCNQI adducts exist in the solid state as single diastereoisomers, but as two interconverting diastereoisomers in solution. Solid- and so...
Article
Full-text available
The decay of the photoluminescence excited in rubrene single crystals by picosecond pulses is measured over 7 orders of magnitude and more than 4 time decades. We identify the typical decay dynamics due to triplet-triplet interaction. We show that singlet exciton fission and triplet fusion quantum yields in rubrene are both very large, and we direc...
Conference Paper
Full-text available
Silicon nanophotonics is considered a key enabler of future photonic-electronic information processing systems. Driven by substantial research investments, photonic integration on silicon-on-insulator (SOI) substrates has reached a degree of maturity that already permits industrial adoption. Silicon-organic hybrid integration (SOH) is a viable exte...
Article
We visualize exciton diffusion in rubrene single crystals using localized photoexcitation and spatially resolved detection of excitonic luminescence. We show that the exciton mobility in this material is strongly anisotropic with long-range diffusion by several micrometers associated only with the direction of molecular stacking in the crystal, alo...
Article
Significant acceleration of the photoluminescence (PL) decay rate was observed in water solutions of two rare earth ions (REIs), Tb and Eu. We propose that the time-resolved PL spectroscopy data are explained by a fluorescence resonance energy transfer (FRET) between the REIs. FRET was directly confirmed by detecting the induced PL of the energy ac...
Article
We have developed a new kind of tellurite glass with composition 70.5TeO 2 –12ZnO–10Na 2 O–7.5Bi 2 O 3 by conventional melting–quenching techniques. A suspended-core fiber (SCF) with a triangular-shaped core (~ 2.9 μm) has been drawn from an extruded perform. Several nonlinear frequency conversion processes are being demonstrated, which point to th...
Article
We determine the wavelength dependence of the two-photon absorption cross section in rubrene single crystals both by direct measurement of nonlinear transmission and from the two-photon excitation spectrum of the photoluminescence. The peak two-photon absorption coefficient for b-polarized light was found to be (4.6 +/- 1) x 10(-11) m/W at a wavele...
Article
We determine the optical losses of DDMEBT planar waveguides and characterize the shelf-life and robustness of DDMEBT thin films used for ultra-fast all optical data processing.
Article
This paper discusses the tellurite fibers for mid-IR applications. Over the past few years, the authors have developed a glass and fiber infrastructure and have demonstrated their capability to synthesize and characterize glasses, fabricate preforms and draw fibers, and demonstrate various optical effects in these. However, the originality of this...
Article
Full-text available
We report on tunable parametric generation (PG) and third-harmonic generation (THG) in a 2.9-µm core bismuth-tellurite holey glass fiber. The maximum conversion efficiency was measured to be 0.1% and 0.06% for PG and THG respectively.
Article
a b s t r a c t We characterize size-dependent carrier relaxation dynamics of partial laser structures containing quantum dashes by time-resolved degenerate four wave mixing between 1.2 and 1.6 mm.
Conference Paper
Small organic molecules with large third-order nonlinearity compared to their size create a high optical quality organic coating when vapor-deposited on any substrate, and deliver all-optical switching without two-photon absorption to the silicon photonics platform.
Article
Full-text available
We determine the refractive index dispersion of a quaternary tungsten-tellurite glass over a broad spectral range from 0.4 to 3 mu m from the wavelength dependence of the phase matching conditions for third-order nonlinear optical frequency conversion. We discuss the optimum phase-matching geometries for this task and obtain the wavelength-dependen...
Conference Paper
Full-text available
CMOS-compatible silicon photonics combined with covers of χ<sup>(2)</sup> or χ<sup>(3)</sup>-nonlinear organic material allows electro-optic modulators and all-optical wavelength converters for data rates of 100 Gbit/s and beyond. The devices are not impaired by free carriers.
Article
Homoconjugated push–pull chromophores are obtained by [2+2] cycloaddition of 2,3-dichloro-5,6-dicyano-p-benzoquinone to anilino or ferrocene donor-substituted alkynes, and in one case a spiro compound (see picture: examples with corresponding electron adsorption spectra; C gray, Cl green, N blue, O red). Significant third-order optical nonlineariti...
Article
Donor-substituted cyanoethynylethenes (CEEs) are planar push–pull chromophores featuring intense intramolecular charge-transfer (CT) interactions and high third-order optical nonlinearities. Their thermal stability allows for the formation of crystalline thin films by vapor-phase deposition. On the other hand, high-quality amorphous thin films are...
Article
Full-text available
We demonstrate ultrafast optical signal processing up to bitrates of 170 Gbit/s. Silicon-on-insulator waveguides are defined by CMOS technology. In addition, an organic cladding pro-vides either X(3) or X(2)-nonlinearities that are not impaired by two-photon absorption. With a proper waveguide design, the influence of two-photon absorption in silic...
Article
Full-text available
Excitons in rubrene single crystals dissociate into free charge carriers via two mechanisms whose relative importance depends on the illumination wavelength through the optical penetration depth into the crystal. The first mechanism is defect-induced dissociation in less than 10 ns after photoexcitation. For low photoexcitation densities, about 10%...
Article
a] Milan Kivala, [a] Berta Camafort Blanco, [a] Benjamin Breiten, [a] W. Bernd Schweizer, [a] Philip R. Laporta, [b] Ivan Biaggio, [b] Eike Jahnke, [c] Rik R. Tykwinski, [c] Corinne Boudon, [d] Jean-Paul Gisselbrecht, [d] and François Diederich* [a] Keywords: Alkynes / Charge transfer / Chirality / Conjugation / Cycloaddition / Cascade reactions Ch...
Article
Full-text available
We discuss the potential functionalities of a mixed tellurite-chalcogenide glass where alternate oxygen atoms in a TeO(2) vitreous network are substituted with either sulfur or selenium atoms. We calculate the microscopic linear and nonlinear polarizabilities of chains with a finite number (n) of TeOX (X = S or Se) units from ab initio quantum chem...
Article
Full-text available
All-optical wavelength conversion of 56 Gbit/s NRZ-DQPSK based on four-wave mixing is demonstrated in a silicon-organic hybrid strip waveguide operated in TM mode.
Article
Full-text available
The silicon-organic hybrid (SOH) platform is reviewed. The SOH approach is a promis-ing CMOS compatible photonic platform enabling ultrafast nonlinear signal processing in compact silicon photonic devices. ©2010 Optical Society of America OCIS codes: (130.4310) Nonlinear; (130.2790) Guided Waves; (160.4330) Nonlinear optical materials; (190.3270) K...
Conference Paper
Small conjugated molecules with donor-acceptor substitution have record breaking third-order polarizabilities and form homogenous organic films with high optical quality that are ideal for integrated nonlinear optics and for incorporating with nanostructured substrates.
Article
Vapor deposition of organic molecules for ultrafast all-optical switching on silicon has been reported. The main challenge for applications is the necessity to develop a solid-state organic material that not only reflects the high optical nonlinearities of its molecular components, but that also has a high optical quality and can be easily and effi...
Conference Paper
Full-text available
Silicon signal processing at bitrates beyond 100 Gb/s is demonstrated. A new enabling platform is reviewed, which relies both on silicon-based CMOS technology for waveguide fabrication, and on an organic cladding providing nonlinearity for switching.
Conference Paper
Full-text available
Error-free wavelength conversion using cross-phase modulation (XPM) is shown in a passive 4 mm long silicon-organic hybrid waveguide. This is the first XPM demonstration in a CMOS compatible chip for bitrates of 42.7 Gbit/s at communication wavelengths.
Article
Full-text available
Geometry, nonlinearity, dispersion and two-photon absorption figure of merit of three basic silicon-organic hybrid waveguide designs are compared. Four-wave mixing and heterodyne pump-probe measurements show that all designs achieve high nonlinearities. The fundamental limitation of two-photon absorption in silicon is overcome using silicon-organic...
Article
A new type of tellurite chalcogenide glass is proposed and simulated at the microscopic molecular level using GAMESS. The ab initio study shows that the optical linear polarizability alpha and second-order hyperpolarizability gamma per unit increase ~1.5 times and ~2 times respectively by replacing O with S in chain-like structures TeTe (X=O or S),...
Article
We present an organic supramoleular assembly with a high off-resonant third-order susceptibility, easy fabrication into homogeneous thin films, and high-optical quality for ultra-fast all optical data processing.
Article
Silicon-organic hybrid waveguides are fabricated by vapor deposition of a small molecule with large third-order nonlinearity on silicon-on-oxide slotted waveguides. The deposited material fills the slot homogenously, and has high optical quality.
Article
Full-text available
All-optical wavelength conversion at 42.7 Gbit/s over 18 nm in a passive 4 mm long silicon-organic hybrid waveguide is demonstrated based on four-wave mixing. No patterning effects are observed.
Article
Full-text available
Integrated optical circuits based on silicon-on-insulator technology are likely to become the mainstay of the photonics industry. Over recent years an impressive range of silicon-on-insulator devices has been realized, including waveguides1, 2, filters3, 4 and photonic-crystal devices5. However, silicon-based all-optical switching is still challeng...
Article
A new type of tellurite glass has been synthesized with composition 70%TeO2-25%ZnO-5%ZnS. The glass is of black color, indicating a high absorption in the visible range. However, transmittance measurements show the same glass to be transmitting in the near-IR range, between 2 mum and 6 mum. XPS data reveal the existence of Zn-O-S and a reduction of...
Article
The creation of a high-quality molecular assembly with a high third-order optical nonlinearity using organic molecular beam deposition was reported. The best homogeneity and linear optical properties for the vapor deposited organic film were obtained with the molecule 2-[4-(dimethylamino)phenyl]-3- ([4(dimethylamino)phenyl]-ethynyl)buta-1,3-diene-1...
Article
In spite of the great interest in organic field effect transistors, many of their aspects are still not well understood. In particular, efforts to uncover the origin of the contact resistance and the underlying physics have lead to apparently contradictory results. Here we show that all these features can be understood by a unified description that...
Conference Paper
Nonlinear losses of highly nonlinear silicon/organic photonics slot waveguides are analyzed. Unlike silicon strip waveguides, slot waveguides do not show absorption related speed limitations up to highest input powers.
Conference Paper
Silicon-on-insulator (SOI) is a promising material system for dense on-chip integration of both silicon photonic and electronic devices. The high refractive index of silicon enables strong light confinement and compact lowloss devices at telecommunication wavelengths. In addition, on-chip nonlinear optical signal processing becomes feasible, becaus...
Article
Full-text available
The rubrene molecular crystal has the unique property of showing a strong photoconductivity for light wavelengths that are close to the absorption edge. We studied the microsecond dynamics of the photoconductivity induced by short light pulses to characterize the way in which photoinduced excitons efficiently ionize to produce free charge carriers....
Article
Full-text available
A silicon photonics slot waveguide with a record nonlinearity of 104 000 W-1km-1at 1.5 μm is reported. We demonstrate demultiplexing of 130 Gbit/s signals to 10 Gbit/s using FWM in a 6 mm-long device.
Chapter
This chapter presents a discussion of the recording speed in photorefractive materials, the parameters that influence it under various circumstances of continuous wave and pulsed recording, and the experimental conditions under which the recording speed is determined in the simplest way by readily identifiable material parameters. This leads to all...
Conference Paper
By using short wavelength tunable optical pulses to excite a transient photoconductivity and to write a transient photorefractive grating we uncover the unique mechanisms of photocarrier generation in Rubrene and of charge transport in DAST.
Article
The authors use donor-acceptor substitution to increase the third-order polarizability gamma of small cyanoethynylethene molecules by lowering the energy corresponding to the first optical transition. They identify a weak power-law dependence for gamma depending on the number of conjugated electrons that separate the donor and acceptors (N1.5), whi...
Article
This article investigates a series of donor-acceptor chromophores that show an extraordinarily large third-order optical nonlinearity compared to their molecular size. With these compounds, the authors are able at the same time to approach the fundamental limit for the molecular third-order polarizability within about an order of magnitude and to o...
Chapter
The Holographic Time of Flight (HTOF) method for the all-optical, contact-less investigation of charge transport in non-centrosymmetric insulators and semiconductors is based on the instantaneous photoexcitation of a spatially modulated distribution of charge carriers and on the linear electro-optic (Pockels) effect to visualize a charge-displaceme...
Article
Full-text available
We report on the frequency dependence of the high two-photon absorption (TPA) crosssections (¿TPA) measured in small organic molecules. The best molecule has a ¿TPA= 9 ± 3 �? 10¿48 cm4s/photon, up to 10 times that of AF-50.
Article
A top-emitting 230 dots/in. monochrome active-matrix polymer light-emitting diode (PLED) display having the VGA format and fabricated on a flexible steel foil utilizing the polycrystalline silicon thin-film transistor (TFT) technology is reported. The pixel circuitry architecture consists of the conventional two TFT circuitries made of two p-channe...
Article
A series of donor-acceptor chromophores was prepared in which the spacer separating 4-dimethylanilino (DMA) donor and C(CN)(2) acceptor moieties is systematically varied. All of the new push-pull systems, except 4 b, are thermally stable molecules. In series a, the DMA rings are directly attached to the central spacer, whereas in series b additiona...
Article
We review the molecular third-order polarizability of a series of compact two-dimensional cyanoethynylethene derivatives and show that the best molecules have a nonlinearity that is only by a factor of 50 lower than the fundamental limit derived by Kuzyk, which is revealed to be a quite useful concept in discussing the observed trends in molecular...
Article
We discuss the high specific nonlinearities of a new class of organic molecules and their assembly, by vapor deposition, into single-component homogeneous thin films for third-order nonlinear optics.