Discrete frequency mid-infrared spectroscopic imaging using quantum cascade lasers

Abstract

Infrared (IR) spectroscopic imaging is an analytical technique that directly images the spatial distribution of chemical components within a sample in the absence of external contrast agents. This is especially advantageous with biological samples where the mid to far-infrared wavelength range corresponds with the vibrational modes of functional groups in many organic molecules. In recent years, the technology enabling discrete frequency infrared (DFIR) spectroscopic microscopy has undergone many substantive changes due to rapid developments in quantum cascade lasers (QCL) in terms of their output power, beam stability, and wavelength tuning range. In this dissertation, we present the research and development of several state-of-the-art microscopy systems that have advanced what was previously possible with industry standard instruments. Through drastic improvements in imaging speed and resolution, as well as reductions in noise and aberrations, our systems serve as a flexible platform with capabilities that open new avenues for research and clinical interests.