Current activities of the team in extreme photonics emphasise research beyond current limits in the properties of light and its interaction with matter – temporal, spectral, spatial and quantum. Members of the team are conducting cutting edge experimental and computational research at several scientific frontiers in extreme photonics – attosecond and sub-wavelength science, laser processing of materials, nanophotonics, green energy technologies, quantum information, high-speed communications and biochemical sensing. There are also several ongoing collaborative projects among the team members.
Students and postdoctoral fellows joining the CREATE program will be integrated into these research activities. Below we describe key research areas that highlight current status and future developments in the field of extreme photonics.
Temporal aspects of extreme photonics: Direct imaging of ultrafast processes in matter requires the shortest light pulses. For example, electrons in an atom or a molecule orbit on the attosecond time scale. Until recently, direct optical imaging of such ultrafast processes has been out of reach of the scientific community. Only indirect inferences could be drawn using collision spectroscopy. Members of the team (Corkum, Brabec, Bhardwaj) are involved in making visible light pulses that are only a period or two in duration and producing attosecond X-ray pulses that are 50 times shorter than any previous pulse. Corkum and Brabec are two of the founding fathers of attosecond science. Their experimental and computational research opens doors for advanced spectroscopic tools to unravel, manipulate and control some of the fastest events in nature. Our team (Bao and Chen) is also involved in pushing the current limits in high-speed optical communications. They have the expertise in generation, detection, transmission and signal processing of ultra-high bit rate data beyond 1Tbits/s limit. Their experimental and computational research on nonlinear pulse propagation (optical solitons) in optical fibers will break the current barriers.
Spatial aspect of extreme photonics: Non-invasive manipulation of matter on nanometer dimensions is key to the development of new technologies in several areas of science. Light provides an opportunity but the spatial resolution is often restricted by the diffraction limit to half the wavelength of light. Drs. Bhardwaj, Corkum and Rammuno have the expertise in breaking this barrier by modifying material properties through nonlinear multiphoton interaction of light. Their research enables nanostructuring of materials with light that can be used to develop novel photonics devices and sensors (in collaboration with Drs. Bao and Chen). Processing capabilities of light can be extended to biomaterials as well. In collaboration with Dr. Munger, who has the expertise in ophthalmology, the team will study tissue processing by lasers. Since the spatial resolution that can be achieved with light is still poor in soft matter, due to weak nonlinearity of the light-matter interaction, the team will combine laser pulses with small metal nanoparticles to control light at the nano-scale in soft matter.
Manipulation of light with nanostructured materials: Members of the team (Berini, Hinzer, Williams) have extensive expertise in guiding and controlling light using different types of nanostructures. The interaction of light with metal-dielectric or semiconductor features enable the control of light using nanostructrures (1/100th of its wavelength). This leads to new imaging tools that exploit confinement and local field enhancements near nanostructures, novel biochemical sensors that perform down to the single molecule level, and new devices that merge electronics and photonics at the nanoscale. These devices will overcome the performance limitations of electronic circuits in speed, and the bulkiness of conventional photonics circuits, thereby addressing the size compatibility issue.
Quantum aspect of extreme photonics: This field of research deals with quantum mechanical aspects of light and its interaction with matter. In matter, interactions between electrons are responsible for a large number of macroscopic phenomena such as ferromagnetism and superconductivity. However, these electrons are not independent entities – a consequence of the quantum nature of matter – but are correlated. Members of the team are investigating such correlated electron dynamics in complex systems (including atoms, molecules and quantum dots) both experimentally (Drs. Corkum, Bhardwaj and Williams) using optical techniques and theoretically (Drs. Hawrylak and Brabec) by developing many body quantum codes. Such correlations not only provide valuable insight into biochemical reactions but lead to complex behavior in finite quantum systems such as semiconductor nanostructures for quantum information applications (Drs. Hawrylak and Williams). The quantum nature of light imposes limitations on the ultimate performance of an optical system. For example, in optical communications a light pulse must contain at least one photon for reliable detection. There should be no losses or dark counts during the detection process. Such limitations restrict the capacity of optical communications systems. Members of our team (Drs. Brabec, Hawrylak and Williams) are developing tools to understand the quantum nature of light and matter that offers new ways to enhance the performance of optical communication systems.