Description

This fellowship opportunity at the Naval Research Laboratory (NRL) focuses on investigating ultrafast dynamical processes in condensed phase materials using advanced spectroscopic techniques. The research emphasizes the use of terahertz time domain spectroscopy (THz-TDS) combined with waveguide structures to measure vibrational spectra with enhanced sensitivity and spectral resolution. Applications include detecting threat solids such as explosives and threat vapors.

The project employs Fourier-transform methods applied to nonlinear-optical transients to study Raman-active vibrational structures in the spectral range of 1 to 800 cm⁻¹, particularly useful for rapidly dephased intermolecular modes in disordered media like liquids and amorphous solids. Additional techniques include vibrational pump-probe spectroscopy in the mid-infrared and THz-TDS in the far-infrared, providing insights into dipole-allowed spectra.

Research also explores energy relaxation and dephasing mechanisms of intermolecular modes, mechanical properties of structural coordinates, and dynamics of super-cooled and glass phases in various materials such as glass-forming liquids, polymer glasses, and liquid crystals over femtosecond to microsecond timescales. Other projects involve studying photophysical and carrier dynamics in thin-film materials and semiconductor materials like low-temperature grown GaAs.

Facilities available include mode-locked femtosecond Ti:sapphire lasers, regenerative amplifiers, optical parametric amplifiers, dye lasers, and the necessary electronic and optical equipment for nonlinear-optical experiments.