Materials for third order nonlinear optics (Conference Presentation)

Organic materials with large third-order nonlinearities in the near-infrared spectral regime are critical in the development of photonic devices to be utilized in all-optical signal processing. We have developed polymethine materials, specifically bisdioxaborine-terminated polymethine dyes, which possess large ultrafast third-order nonlinearities and low nonlinear loss all in the near-infrared spectral regime. An extended bisdioxaborine polymethine anion exhibited the largest value of gamma (third-order microscopic nonlinearity) at 1.3 mum (|gamma| = 5.7 x 10-32 esu) and showed no characteristics of symmetry breaking, unlike other polymethines of similar lengths. A neat film of this molecule maintained relatively low linear loss in the near-infrared and showed a large third-order macroscopic nonlinearity at 1.3 mum (|chi(3)| = 3.6 x 10-10 esu), with a temporal response of less than 8 ps. Furthermore, the real part of chi(3) was nearly an order-of-magnitude larger than the imaginary component. Consequently, this material exhibited good figures of merit for all-optical signal processing throughout the entire telecommunications band.

Linear and Nonlinear Polarizability: a Primer Second-Order Nonlinear Optical Processes in Molecules and Solids Third-Order Nonlinear Optical Effects in Molecular and Polymeric Materials Nonlinear Optical Properties of Molecules and Materials Electronic Hyperpolarizability and Chemical Structure Electrooptic Polymer Waveguide Devices: Status and Applications Waveguiding and Waveguide Applications of Nonlinear Organic Materials Nonlinear Optical Materials: The Great and Near Great Donor- and Acceptor-Substituted Organic and Organometallic Compounds: Second-Order Nonlinear Optical Properties Use of a Sulfonyl Group in Materials for Nonlinear Optical Materials: A Bifunctional Electron Acceptor Organic and Organometallic Compounds: Second-Order Molecular and Macroscopic Optical Nonlinearities Chemistry of Anomalous-Dispersion Phase-Matched Second Harmonic Generation Applications of Organic Second-Order Nonlinear Optical Materials Chromophore-Polymer Assemblies for Nonlinear Optical Materials: Routes to New Thin-Film Frequency-Doubling Materials Novel Covalently Functionalized Amorphous *y^2 Nonlinear Optical Polymer: Synthesis and Characterization Second-Order Nonlinear Optical Polyphosphazanes Molecular Design for Enhanced Electric Field Orientation of Second-Order Nonlinear Optical Chromophores Nonlinear Optical Chromophores in Photocrosslinked Matrices: Synthesis, Poling, and Second-Harmonic Generation Thermal Effects on Dopant Orientation in Poled, Doped Polymers: Use of Second Harmonic Generation Organic Polymers as Guided Wave Materials Observing High Second Harmonic Generation and Control of Molecular Alignment in One Dimension: Cyclobutenediones as a Promising New Acceptor for Nonlinear Optical Materials Strategy and Tactics in the Search for New Harmonic-Generating Crystals Development of New Nonlinear Optical Crystals in the Borate Series What is Materials Chemistry? Defect Properties and the Photorefractive Effect in Barium Titanate Defect Chemistry of Nonlinear Optical Oxide Crystals From Molecular to Supramolecular Nonlinear Optical Properties Control of Symmetry and Asymmetry in Hydrogen-Bonded Nitroaniline Materials Molecular Orbital Modeling of Monomeric Aggregates in Materials with Potentially Nonlinear Optical Properties Strategies for Design of Solids with Polar Arrangement Ferroelectric Liquid Crystals Designed For Electronic Nonlinear Optical Applications Model Polymers with Distyrylbenzene Segments for Third-Order Nonlinear Optical Properties Composites: Novel Materials for Second Harmonic Generation Clathrasils: New Materials for Nonlinear Optical Applications Inorganic Sol-Gel Glasses as Matrices for Nonlinear Optical Materials Intrazeolite Semiconductor Quantum Dots and Quantum Supralattices: New Materials for Nonlinear Optical Applications Small Semiconductor Particles: Preparation and Characterization Synthetic Approaches to Polymeric Nonlinear Optical Materials Based on Ferrocene Systems Transition Metal Acetylides for Nonlinear Optical Properties Third-Order Near-Resonance Nonlinearities in Dithiolenes and Rare Earth Metallocenes Nonlinear Optical Properties of Substituted Phthalocyanines Nonlinear Optical Properties of Substituted Polysilanes and Polygermanes Design of New Nonlinear Optic-Active Polymers: Use of Delocalized Polaronic or Bipolaronic Charge States New Polymeric Materials with Cubic Optical Nonlinearities: From Ring-Opening Metathesis Polymerization Polymers and an Unusual Molecular Crystal with Nonlinear Optical Properties Quadratic Electrooptic Effect in Small Molecules Third-Order Nonlinear Optical Properties of Organic Materials

20 - Nonlinear optics in communications: From crippling impairment to ultrafast tools

Thin single crystal films of organics; waveguiding in PTS films

Tuning the third-order nonlinear properties of graphene by hybrid method is of great significance in nonlinear optics research. ZrO2/reduced graphene oxide (RGO) composites with different ZrO2 concentrations were prepared by a simple hydrothermal method. The morphology and structure show that ZrO2 nanoparticles were uniformly dispersed on the surface of graphene nanosheets. The nonlinear optical (NLO) characteristics of composites with different ZrO2 concentrations were studied by the Z-scan technique of 532 nm picosecond pulsed laser. The results showed that ZrO2/RGO composites had saturated absorption and positive nonlinear refraction characteristics. Meanwhile, the third-order nonlinear susceptibility of the ZrO2/RGO composite with a 4:1 mass ratio of ZrO2 to graphene oxide could reach 23.23 × 10−12 esu, which increased tenfold compared to RGO, and the nonlinear modulation depth reached 11.22%. Therefore, the NLO characteristics could be effectively adjusted by controlling the concentration of ZrO2, which lays a foundation for further research on the application of ZrO2/RGO composites in NLO devices.

Nonlinear optical responses of carbon quantum dots anchored on graphene oxide hybrid in solid-state transparent monolithic silica gel glasses

Stimulated by a recent experimental report [Hales JM et al. (2010) Science 327:1485-1488], two-photon absorption and third-order optical nonlinearities of selenopyrylium- and bis(dioxaborine)-terminated polymethine dyes (called SE-7C and DOB-9C) used for all-optical switching were investigated theoretically with time-dependent DFT (TD-DFT) and response theory as well as visualized real-space analysis. The calculated results for the first hyperpolarizability and second hyperpolarizability demonstrated that the two molecules both have large third-order optical nonlinearities. Using real-space analysis, we were able to visually determine that in the one-photon absorption (OPA) process, the first singlet excited state of SE-7C and DOB-9C is an intramolecular charge transfer (ICT) excited state with strong absorption, while the second excited state of these dyes (also termed the "ICT state") shows weak absorption. However, in the two-photon absorption (TPA) process, a larger TPA absorption cross-section was predicted for the second excited state. In this paper, we describe the properties of the S2 excited state, incorporating charge transfer and the transition moment, via real-space analysis, which was very important for understanding the TPA characteristics of the S(2) state.

We present a systematic investigation of the poling-induced electrooptic (EO) effect in germanium and nitrogen codoped channel waveguides. The channel waveguides show attractive properties: (1) almost polarization independent EO effect; (2) a flat frequency response with the modulation frequency up to 100 kHz; and (3) low linear loss and low polarization dependent loss, which demonstrate great technological potential.

Quantum chemical study on the high nonlinear optical effect of MMONS

Conjugated polymers such as polydiacetylenes possess large third-order optical susceptibilities in their transparent-gap regions, making them potentially attractive materials for applications in all-optical signal processing. To investigate this potential, we have developed techniques for fabricating a variety of integrated optical structures, such as channel-waveguide directional couplers, from thin films of soluble polydiacetylenes.1 At 1.06 µm these devices exhibit thermal switching at average power levels of 10 mW, and the ultrafast electronic part of the device reponse is dominated by two-photon absorption (TPA), which gives rise to intensity-dependent transmission.2 Spectrally resolved measurements of this TPA have been analyzed in terms of a correlated-electron model, and it has been found, contrary to expectation, that the nonlinear properties of the polymer are dominated by states lying well above the one-photon energy gap.

In this paper, a novel surface plasmon polariton (SPP) based all-optical 1× 2 demultiplexer, which is based on a modified Y-branch structure and a controllable switching module, is presented. In the modified Y-branch structure, which acts as an ideal wide-band splitter, the width of the branches are chosen as one half the input waveguide. The switching module is constructed using two nano-plasmonic racetrack-shaped disk resonators which are side coupled to the branches of the Y-branch structure. It has been shown that using a pump light power, the transmissions of the input signal into the output ports can be controlled. The simulation results are based on the two dimensional finite-difference time-domain (2D FDTD) method. In the proposed device, the “on” state transmission coefficients and the extinction ratios (measured at the output ports), for the pump light source with the wavelength of 660 nm and the intensity of 1.75 MW/cm2, are about 0.74 and 28.75 dB, respectively. Furthermore, in this case, the switching times of the proposed device, measured at the port 1 and port 2, are about 100 fs and 180 fs, respectively. It is expected that the proposed device can find applications in all-optical signal processing.

With its unique and exclusive linear and nonlinear optical characteristics, epsilon-near-zero (ENZ) photonics has drawn a tremendous amount of attention in the recent decade in the fields of nanophotonics, nonlinear optics, plasmonics, light-matter interactions, material science, applied optical science, etc. The extraordinary optical properties, relatively high tuning flexibility, and CMOS compatibility of ENZ materials make them popular and competitive candidates for nanophotonic devices and on-chip integration in all-optical and electro-optical platforms. With exclusive features and high performance, ENZ photonics can play a big role in optical communications and optical data processing. In this review, we give a focused discussion on recent advances of the theoretical and experimental studies on ENZ photonics, especially in the regime of nonlinear ENZ nanophotonics and its applications. First, we overview the basics of the ENZ concepts, mechanisms, and nonlinear ENZ nanophotonics. Then the new advancements in theoretical and experimental optical physics are reviewed. For nanophotonic applications, the recent decades saw rapid developments in various kinds of different ENZ-based devices and systems, which are discussed and analyzed in detail. Finally, we give our perspectives on where future endeavors can be made.

We show two of our work on multi-mode nonlinear optical process. In a Ta₂O₅ waveguide of 100 nm in thickness, 8 μm in width and 4.3 mm in length, all-optical signal switching and power limiting operation were demonstrated by nonlinear multi-mode interference while the modes were properly excited by a near infrared pulse at the wavelength of 1064 nm, peak power of 100 W and the pulse duration of 1 ps. In supercontinuum process, a waveguide of 760 nm in thickness and 1.1 μm in width was designed where different guided modes were anomalously dispersive at different wavelengths. Supercontinuum spectrum spanning over an octave with high degree of spectral flatness was excited by a 100-fs laser pulse at the wavelength of 1030 nm. Spectral synthesis with a diffraction gratings mapped the spectral components attributed to specific waveguide modes. It inferred the possibility to engineer supercontinuum generation through waveguide-mode arrangement.

The semicarbazone of p-anisaldehyde (SPAS) is a novel organic nonlinear optical material. The SPAS has been synthesized and the solubility studies were carried out in the temperature range 30-60 °C. Single crystals of SPAS have been grown following the slow evaporation technique and the unit cell parameters have been evaluated by single crystal X-ray diffraction technique. The UV-Visible, FT-IR and 1HNMR spectra have been recorded to characterize the grown crystal. The thermogravimetric and differential thermal analysis of the grown crystal revealed that there is no phase transformation in SPAS, and its thermal stability was found to be good. The dielectric measurement was made as a function of frequency (50 Hz - 5 MHz). The second harmonic generation in the sample was confirmed by the Kurtz powder technique.

Explicit formulation of second and third order optical nonlinearity in the FDTD framework