Dr. Daniel R. Solli
University of GŲttingen (Physics Dept.)
Nonlinear systems are known for their counterintuitive properties, including dramatic sensitivities to initial conditions. Complex dynamics can be excited when short optical pulses propagate through optical fiber. Striking examples include modulation instability (a form of spontaneous pattern formation) and supercontinuum generation (large spectral broadening). Rare events known as optical rogue waves, analogous to freak ocean waves, have also been observed.
Real-time Measurements and Ultrafast Phenomena
Real-time measurements can uncover latent phenomena amidst non-repetitive dynamics, which are not resolved by techniques that average in time. Despite their ephemeral nature, singular events and other non-repetitive occurrences can play defining roles in a systemís long-term behavior. In ultrafast optical systems, cutting-edge experimental techniques are required to achieve real-time performance. The time-stretch transformation enables detailed measurements of ultrashort waveforms at extremely high repetition rates with a real-time oscilloscope.
Electrons may be ejected from metallic nanostructures by nonlinear interaction with ultrashort pulses of light. This photoemission is highly localized in space and time, and the trajectories of the emitted electrons can be controlled with the transient optical field. Mid-infrared and terahertz fields are of special interest in nonlinear photoemission and particle manipulation.
Many nonlinear optical effects can be induced in silicon nano waveguides. My topics of interest in this area have included stimulated supercontinuum generation, CARS conversion, inverse Raman scattering, periodic poling with modulated stress fields, broadband Raman amplification, and the limiting effects of free carriers.
Imaging and Vision
Independently of my other efforts, I am involved in the development of new techniques for real-time image processing and computer vision. Business trends, current events, and popular interests highlight the widespread deployment and growing demand for advanced imaging capabilities. Real-time, energy-efficient methods are key to many critical applications.