Juliet Gopinath

Infrared sources

The infrared region, from 3-20 microns, contains many vibrational resonances of molecules. The infrared is often called the 'chemical fingerprint' region with many applications in sensing. Quantum-cascade laser technology is the basis for many sources in the region, but the lasers are limited in spectral range, bandwidth, and power. Other options for sources will be investigated, ranging from direct generation with solid-state or fiber lasers, to nonlinear conversion of near-infrared sources. The goal is the development of compact, efficient, broad-bandwidth, high-power infrared sources with potential extensions to the THz regime. Research opportunities on this project range from materials characterization to laser development and sensor engineering.

Semiconductor lasers

Semiconductor lasers, with their potential for efficient and compact operation are the ideal source for many applications including sensors, optical clocks, pump sources, data storage, and lidar. High efficiency operation and large wavelength tuning ranges are achievable, but the application space is constrained by power and pulse energy and pulse width limits. Techniques to improve the performance of semiconductor lasers will be investigated. The goal is the development of high power, single mode, highly efficient lasers for applications that currently require solid-state and fiber lasers. Development will include design and simulation, materials study, fabrication and device testing.

Ultrafast spectroscopy

Spectroscopy, both in the time and frequency domain, can be used as a tool for both device design/characterization and for fundamental scientific investigations. Bulk materials, nanoparticles, novel materials and broadband devices can all be investigated with spectroscopy. Characterization of scattering times and nonlinearities is critical for the design of integrated photonic devices such as lasers and switches. Development will include modeling and simulation, fabrication, and experimental design and testing.

Optofluidics

Optofluidics, the combination of microfluidics, nanotechnology and photonics, offers some distinct advantages over current photonics technology: tunability, high index contrast, and dynamic system reconfiguration. Recent developments include switches, microscopes, reconfigurable lenses, and liquid core waveguides. Specifically, the group is interested in developing microfluidic devices based on nonlinearities of nanoparticles in solution. Lasers compatible with microfluidic devices will also be studied. These sources will be integrable with existing microfluidic technology, allowing the development of 'lab-on-chip' systems for biological applications.