Fundamental and applied science is a key pillar to the activities of the IOS and so is fortunate to have a variety of world-class faculty members from the Departments of Chemistry, Physics, Material Science and Engineering, and Electrical and Computer Engineering.
Our research focuses on nonlinear optics and in particular the propagation of solitary waves in periodically structured materials. Current research interests include nonlinear optical effects in quantum dot, quantum dash and quantum well semiconductor optical amplifiers, photonic crystals, Metamaterials, optical frequency conversion, surface plasmons and nanoscale photonic wires for high density integrated optics.
Extensive clean room facilities for the fabrication of nanoscale devices including e-beam lithography capable of generating features sized down to 10
Biophotonics, non-linear multimodal microscopy, imaging, lasers and non-linear optics, cellular biophysics
Our research focuses on the development of new imaging modalities for multimodal non linear microscopy. Currently we employ second harmonic generation, third harmonic generation and multiphoton excitation fluorescence contrast mechanisms, which are generated simultaneously after femtosecond pulse excitation. Our microscopes are tailored to image non-invasively live cells and subcellular organelles. We investigate intracellular dynamics in photosynthetic systems, research contractility mechanisms in cardiac and skeletal muscle cells, and study structural organization of cancerous tissue.
Laser excitation sources
For the past decade there has been rapidly growing interest in utilizing the spin degree of freedom in electronics. This rapidly expanding field of spin based electronics (spintronics) has exploited metal based devices to bring about a revolution in magnetic sensors and computer hard drive density. However a device that exploits the spin of the electron for computation still remains elusive. We explore the optical properties of materials that offer unique possibilities to manipulate spins. In addition to exploring the origin of the magnetic properties of these compounds, we are actively engaged in exploiting their properties for future novel devices.
Materials where two or more interactions compete are typically called Strongly Correlated Electron systems. In the past two decades there has been a resurgance of interest in understanding these compounds. Strongly Correlated Electron systems include a wide variety of topics at the forefront of condensed matter including: superconductivity, multiferriocs, and non Fermi liquid behavior.
Organic electronic materials (polymers and small molecules), organic solar cells, photoactive materials
Prof. Bender is an established expert in the field of organic electronic materials, specifically in their industrial application to organic photoreceptive devices. As an industrial researcher, he has filed over 65 US Patents and over time has authored or co-authored 17 peer reviewed papers in the fields of organic electronic materials and polymeric structures. His new laboratory utilizes a combination of computer aided molecular modeling, synthetic chemistry (polymers and small molecules) and post synthetic characterization pursuing the design, engineering and application of new materials for application in plastic/organic solar cells.
Our research focuses on synthetic strategies, properties and potential applications of nanostructures. We are particularly interested in exploring the roles that quantum mechanics and the discrete nature of electronic charge play in nanoscale electronics. To this end, we have constructed various devices such as 1) a scanning tunneling-atomic force microscope – a hybrid instrument that can simultaneously measure current with atomic resolution and force with single electron sensitivity; and 2) break junctions – a novel configuration of electrodes that allows studies of charge transport through individual nanostructures. We have used these devices to study charge transport through nanostructures with single electron sensitivity.
Viewing nanostructures as “artificial atoms” or building blocks for materials, we are also synthesizing “artificial materials” with completely new and widely varying properties. By choosing the nanostructures and the manner in which we assemble them judiciously, we have found it is possible to make materials with properties that range from insulating to metallic and everything in between. We are using these materials as a test bed to explore charge transport phenomena such as hopping, scattering, quantum interference, and wave function localization – delocalization transition with unprecedented control. We have shown recently that these “artificial materials” can be used to make devices that mimic semiconductor-based transistors that are widely used as switches and memory storage.
Scanning tunneling microscopy, atomic force microscopy, Fourier transform infrared spectroscopy, metal film deposition, cryogenics, electronics characterization.
Probe microscopy, interfacial chemistry, nanoparticle synthesis and properties, polymers, biopolymers and nanocomposite materials directed protein aggregation.
We are interested in the problem of structure formation by self-assembly, particularly with regards to biological and polymer systems in which control at the nano- to meso- and microscales are a challenge. We use atomic force microscopy for studies of morphology and interactions at the nanometer scale, to gain understanding of what drives the assembly into well defined, functional structures, and with the eventual goal of designing functional materials de novo. Real time imaging with AFM in fluid is used to examine mechanisms of assembly and function in biomolecules. Since small particles are dominated by interfaces, we also utilize other techniques to study interfacial characteristics. In particular, surface nonlinear optics enables us to gain information regarding dynamics and interactions at interfaces, and we invented diffraction-based sensing for measurement of intermolecular interactions.
Scanning probe microscopes and various instruments related to imaging, optics instrumentation and test equipment, facilities for chemical synthesis, facilities for handling of protein and DNA, diffractive optic biosensor.
Molecular biophysics, Single-molecule spectroscopy, Scanning-probe microscopy, Ultrafast laser spectroscopy, Photosynthesis, Protein folding and protein-protein interactions.
We are developing an innovative detection scheme that maximizes the information obtained from individual fluorescing molecules by simultaneously recording the wavelength, the emission time and the polarization for each detected photon. The new instrument provides correlated emission spectra, decays and polarization at each point in a confocal fluorescence image, or at each instant along a single-molecule time trajectory. Very high data readout rate and single-molecule sensitivity makes this setup truly unique. We are a biophysics group focused on the dynamics of protein folding and protein-protein interactions using optical micro-spectroscopy and single-molecule methods. New polarity-sensitive probes will be used to monitor the degree of exposure of hydrophobic residues to the aqueous environment and to map the surroundings of nascent proteins inside the ribosome during translation. This approach will be combined with fluorescence energy transfer (FRET) to study microscopic (un)folded states and folding pathways of proteins in vitro, as well as the folding state of nascent peptides in the cell and their interaction with the ribosome and with molecular chaperones.
Multiparameter fluorescence microscope, single-molecule detection, broadband tuning femtosecond/picosecond laser.
Nano-structuring of semiconductor materials to induce novel optical materials and effects, with application emphasis on photonics devices (e.g. lasers, light emitting diodes, optical signal processing elements and correlated photon pair generation).
Our group has two research foci. The first is to pattern semiconductor crystals on a nanometer scale and hence reengineering their properties with the aim of obtaining new artificial optical materials. Such materials would exhibit properties which are not limited by the properties of the host semiconductor itself. The second focus is to design and implement the devices which benefit from such technologies, namely, designing and fabricating semiconductor negative refraction metamaterials for enhanced imaging resolution via breaking the diffraction limit barrier, achieving phase matching for nonlinear optical processes to obtain optical signal processing integrated circuits, and realizing tunable robust infra red and visible light source for sensing in mobile environmental monitoring as well as life science and point of care medical settings.
Spatially resolved Raman and photoluminescence optical spectroscopy Semiconductor light sources device spectroscopy. Access to nanofabrication facilities.
Laser micro and nano processing for photonics and biophotonics.
Our research group studies and develops novel laser processing technology for defining photonic devices and optical circuits. Novel two- and three-dimensional designs are nanofabricated in optical materials for broad impact in today’s optical communication networks and tomorrow’s biophotonic chips. Two key aspects of laser technology are emphasized: 1) the usefulness of progressively shorter wavelength lasers in micro-structuring “transparent” optical surfaces (glasses, ceramics, semiconductors) and in laser printing of miniature optical devices directly inside optical fibers, optical circuits, and bulk 3-D glasses. 2) the unique advantages of cutting and etching or trimming refractive index in optically transparent materials by controlling the duration and pulse shape of ultra short-light pulses. 3) the possibilities for fabricating three-dimensional nano-optic structures through the interference phenomena of coherent laser light.
Burst-ultrafast laser processing facility, 5-D laser microscopy, F2-laser nanofabrication, 3D Ar-ion holographic fabrication, photonics characterization lab, atomic force microscopy.
Theoretical Optical Physics and Quantum Information.
Our group conducts theoretical physics research in the areas of quantum and classical optics. One of our main current interests is the development of technologies intended to exploit fundamental quantum-mechanical phenomena such as entanglement for communications, computation and metrology. For example, a number of promising technologies have been proposed for building quantum computers. A quantum computer is a device in which data can be stored in a network of quantum mechanical two-level systems (“qubits”). Our research focuses on theoretical aspects of developing these systems, in particular trapped ions, quantum optics and nuclear-spin based solid-state systems.
Photonic crystals, materials science, nano-structured materials, condensed matter physics, optics, atom-radiation interactions, light scattering, semiconductor physics, micro-electronics.
We are presently interested in the development and application of photonic band gap materials, photonic crystals, and photonic crystal fibers for information technology, photo-voltaics, lighting, and clinical medicine. We are studying fundamental properties of light interaction with electronic nano-structures such as quantum dots and quantum wells placed within photonic crystals. This leads to novel low threshold, ultra-fast nonlinear optical effects and novel quantum effects. We are also developing new paradigms for the micro-fabrication of large scale photonic band gap materials, capable of guiding light in the near infrared and visible spectral regions.
Surfaces, interfaces and thin-films materials and devices.
Hybrid nano-organic optoelectronic materials and devices.
PHI 5500 system with X-ray photoelectron spectroscopy and scanning Auger microscope for characterizing surfaces, interfaces and thin films, 1×1 inch research cluster tools for vapor-phase synthesis of nano-organic composite films and devices, 4×4 inch cluster tools for vapor-phase deposition of nano-organic composite films and devices, and various electrical tools for device evaluation.
Ultra-Intense Laser-Matter Interaction; Science of Ultrafast Laser Materials-Processing; Ultrafast Laser-Biotissue Interaction; Biophysics.
In our group, we are interested in a range of science involving the relation of very intense light and matter. In the interaction between the two, each may end up changed, in subtle or in striking ways. It is the relationships within matter, and the relationships of light to itself, which change when the two accommodate each other, and which interests optical and plasma physicists. From this come applications in photonics and biophysics, for materials-processing and medical applications.
Terawatt Chirped-Pulse Amplification Nd:glass Laser System (1J, 1ps) 1 kHz – 100 fs Ti:sapphire system (1 mJ) pulsetrain-burst ultrafast laser processing.
Quantitative biology, mathematical modelling, nonlinear dynamics, stochastic dynamics, fluorescence imaging, and flow cytometry.
Understanding the dynamics of gene regulatory networks is crucial to understanding the underlying principles of cellular behaviour. Our research aims to produce scalable, experimentally validated modelling methods that can be used to study the behaviour of increasingly complex gene networks. We do this by applying a physical chemistry approach and formulating detailed mathematical models of the chemical kinetics involved in transcriptional regulation, i.e. the control of the production of mRNA transcripts. With a detailed picture of the relevant dynamics will come the potential to insert carefully designed control systems into cells and thus to carry out medical interventions directly at the cellular level.
BioNetS modelling software, fluorescence microscopy (bulk and single-molecule), and flow cytometry.
Femtosecond electron diffraction, electron spectroscopies, non-linear optical spectroscopies, solid state laser development, ultrafast laser development, liquid/protein dynamics, biophysics, and laser surgery.
Our research involves developing new light sources such as novel laser sources and also high-brightness femtosecond electron pulsed sources, and applying them to tackle questions of fundamental importance that bear on our understanding of matter, and life. Laser architectures and new concepts in diffractive optics developed in our labs have contributed significantly to the implementation of nonlinear optics; the development of advanced spectroscopy to investigate the structure of matter; the direct measurement of forces that define the hydrogen bond network of liquid water; the study of protein dynamics; and studies on the experimental coherent control of light-matter interaction. Femtosecond electron sources developed in our labs allowed us to capture the first “molecular movie”, enabling the observation of atomic motions during a chemical reaction with femtosecond resolution. Additionally, lasers developed by our group have been commercialized by Lumonics, and are now a significant tool in aerospace wiring and high density electronics manufacturing.
Time resolved femtosecond electron diffraction setup; femtosecond tunable laser sources at UV, visible and mid-IR wavelengths; third and fifth order femtosecond time-resolved Raman spectrometer (visible and IR); pump-probe femtosecond spectrometer combined with pulse shaper system; FROG setup for characterizing laser pulses; nanofluidic flow cells.
Optical tweezers, in vivo microscopy, mechanical sensors
DNA is traditionally viewed as a string of genetic instructions that are controlled through biochemical interactions with regulatory elements. However, DNA is also a polymer whose mechanical properties have been intensely studied, often in an atmosphere far removed from questions of genetic utility. A growing body of evidence is now emerging that connects mechanical features of the DNA to genetic function. In particular, it appears that mechanical twist and tension, felt by DNA within the heavily constrained and continually fluctuating cellular environment, plays an important role in gene expression. This in turn suggests genetic control mechanisms that are complementary to biochemical regulation, with a concomitant significance for our understanding of genetic function.
Materials chemistry and nanochemistry, synthesis-structure-property-function-utility of nanostructured materials
Our research group uses self-assembly synthetic methods to organize inorganic, organic and polymeric building-units into materials with novel chemical and physical properties as well as unprecedented structural features that span Angstrom to micron length scales. We have recently succeeded in making a 3-D silicon photonic crystal with a complete photonic bandgap at 1.5 microns. The main areas that we are working on include nanophotonics, nanoelectronics, nanooptics, nanomagnetics, nanoionics and nanocomposites.
The research team would like to further study nanotechnology’s applications in areas like photonic crystals, structural color, battery, fuel and solar cells, low dielectric constant microelectronic packaging materials, electronic ink, chemical sensors and biosensors, data storage, (photo)catalyst and separation materials.
Diffraction, microscopy and spectroscopy techniques, thermal and adsorption methods of analysis, optical and electrical measurements.
Photoimprinting and electronimprinting molecular scale patterns at surfaces along with Scanning Tunneling Microscopy (STM) instrumentation and theory.
A significant development of recent date is the imprinting of molecular-scale patterns on semiconductor surfaces using light or electrons to cause highly localized reactions. This Molecular-Scale Imprinting (MSI) is followed, atom-by-atom, using STM. The MSI process shows promise as a means to lay down nanostructures (e.g., nanocircuitry). Recent publications include self-assembled nano-corrals and nano-switches.
Three STM’s, room temperature and cryogenic. Ultra high vacuum and surface science tools. Three excimer lasers, cw and tunable.
We are applying biophysical and quantitative methods to the analysis of locomotion and sensory behavior in simple organisms. Our approach is to develop new instrumentation and techniques that allow us to measure and analyze behavioral responses at the motor output level. This systems-level approach will help us detail the molecular, cellular, and neuronal components involved in these pathways, and allows us to ask questions that span a number of traditional scientific boundaries such as sensory biology, systems neuroscience, theoretical neuroscience, and sensory ecology.
Some of our projects are
Labs and offices are located at the CCBR and McLennan Labs
Quantum dot synthesis, ultrafast spectroscopies, excited states and exciton dynamics, and photophysics of solar energy conversion.
Our research contributes to the current understanding of excitons through investigations of various nanostructured systems, with a particular emphasis on elucidating new aspects of exciton photophysics.
A range of complex materials are of interest for study related to photonics, quantum information systems, and solar energy conversion. Such materials are under scrutiny in our laboratory, and include conjugated polymers, semiconductor nanocrystals, carbon nanotubes, and even photosynthetic organisms.
Ultrafast laser facilities (nonlinear optical spectroscopy), advanced photoluminscence facility, and colloidal synthesis laboratories.
Solar polymers, nanomaterials, nanobio interfaces
The overall objective of my research program is to develop organic materials that interact strongly with light and have a structure that maximizes optical and electronic properties. These objectives are important for realizing next-generation high-tech materials, for example, for energy harvesting, optoelectronic diagnostics, and advanced medical imaging. We target polymers and nanostructures that differ significantly from those that presently exist, and where we expect optimal properties and performance. The rational design and synthesis of these new materials allows us to systematically determine the extent that structure controls properties.
At the molecular scale, we are synthesizing a variety new red and infrared light absorbing materials. At the nanoscale, we are developing a myriad of high-aspect-ratio semiconductors. Our mesoscale efforts involve using biomolecules and other strategies to organize polymers and nanostructures into larger composites.
The overall research addresses the challenge of controlling properties through both molecular synthesis and supramolecular interactions. These fundamental goals provide for a natural bridge to several important applications including the development of optoelectronic devices, sensors, and imaging systems. The research is multidisciplinary, fast paced and highly collaborative. We invite you to contact us if you would like to learn more or are interested in joining our research team.
Theoretical physics of quantum and nonlinear optics, optical and spin properties of semiconductors, and the optical properties of artificially structured materials.
Coherent control and transport of carriers, spins, currents, and spin currents in bulk and nanostructure semiconductors; optical properties of ring resonators and other artificially structured materials, and their use in quantum and nonlinear optics; theory of ultrafast electron diffraction and holography; foundational problems in quantum mechanics.
Quantum optics, quantum information processing, laser cooling and Bose-Einstein condensation.
Our main interests are in fundamental quantum-mechanical phenomena, and particularly quantum information processing and the control & characterization of the quantum states of systems ranging from laser-cooled atoms to individual photons.
Cold atoms trapped in optical potentials can be used to store quantum information in the discrete energy levels of their centre-of-mass oscillations. We are investigating decoherence in this system using pulse-echo and 2D spectroscopy techniques, and developing new techniques for quantum error correction to preserve and control the coherence. In parallel, and in collaboration with Paul Brumer, we are studying effects which occur at the quantum-classical boundary when these lattices are used to produce chaotic atomic motion.
Since the first demonstration in 1995 of the Bose-Einstein condensation of trapped alkali atoms below one one-millionth of a degree above absolute zero, over 50 groups worldwide (including 2 at Toronto) have set up similar systems. We believe that such a revolutionary source of atoms will play a role in future atomic-physics research akin to that played over the past 40 years in optics by the invention of the laser. We are in fact using our Bose condensate as an “atom laser,” studying the interactions of a coherent matter wave with potential barriers. Our long-term goal is to study the atoms while they tunnel quantum-mechanically across an optical barrier, and to address long-disputed issues about how long tunneling actually takes.
We have two laser-cooling experiments and several entangled-photon experiments, including one ultrafast spontaneous parametric down-conversion setup, in addition to a cryostat for the study of quantum-dot single-photon emitters. One laser-cooling apparatus is an optical lattice trapping 85Rb, while the other is a TOP trap Bose condensate of 87Rb. A facility under development is an OPO source of narrowband entangled photons at 780 nm suitable for interaction with the trapped Rubidium atoms, as needed for a number of exciting quantum information and quantum nonlinear optics proposals.
As the world faces an unprecedented shortage of energy resources, energy efficiency and power-management have taken center stage. Switched-mode power supplies (SMPS) are the key enabling technology for efficiently delivering the tightly regulated supply voltages required by today’s modern mixed-signal (digital+analog) integrated circuits (ICs) and systems. The SMPS acts as the interface between the energy source, such as a battery, and the load ICs. A typical SMPS uses a combination of high-speed, low-resistance semiconductor switches, energy storage components, sensors and control circuits to regulate one or more output voltages in the presence of disturbances. State-of-the-art SMPS have a power conversion efficiency above 90%. The resulting low heat dissipation allows multiple SMPS to be integrated with their load circuits into a single IC. The clear trend in SMPS research is toward adaptive digital control-loops, increased integration within system-on-chip (SoC) applications, higher efficiency over the full operating range and higher switching frequency, resulting in smaller energy storage components. The long-term goals of the proposed research are to make tomorrow’s power management systems, smaller, more efficient, more robust, and more reliable, while reducing electromagnetic interference (EMI) and environmental impacts.
Ultrafast phenomena in semiconductors, quantum coherence phenomena, and photonic crystals.
Our group explores coherent control of charge and spin in bulk, and reduced dimensional semiconductors. We also carry out fundamental studies on the optical properties of 2D and 3D photonic crystals, periodic dielectric materials which are capable of molding the flow of light in nanophotonic materials.
A variety of picosecond and femtosecond laser systems tunable from the visible to the near-infrared.
Single molecule force spectroscopy, scanning probe microscopy, ANSIM, nanophotonics, nanostructured polymeric materials, biological adhesives.
The goal of our research program is to identify and exploit self-assembly processes of polymers that will enable the fabrication of nanostructured materials with useful electromagnetic, mechanical and physiological properties. The work is strongly interdisciplinary and we collaborate with researchers from most branches of science and engineering.
Nanophotonics: Chemical microscopy: We are developing a new form of extremely high resolution infrared microscopy. This technique will give the ability to identify chemical components of heterogeneous surfaces with sub-20nm resolution under ambient conditions. Nanophotonics for Information Storage: We are developing apertures for heat assisted magnetic recording, in collaboration with photonics engineers.
Electrical Properties of Nanostructured Polymeric Materials: This work in conducting polymers aims to address the need to engineer materials that will make electrical connections between metal electrodes and molecules in molecular electronics.
Atomic force microscopes, ANSIM, thermal evaporator, plasma cleaner, fibre optic UV-Vis-NIR spectrometer, HeNe laser, CO/CO2 laser.