Dissertation Defense

Fiber Based Infrared Lasers and Their Applications in Medicine, Spectroscopy and Metrology

Vinay Varkey Alexander

Fiber based infrared (IR) lasers are attractive for a variety of applications. In medicine, the presence of absorption peaks in the IR for tissue components like adipose and collagen allow selective tissue targeting with minimal damage to non-target tissues. In addition, the low blood and water absorption in the near-IR offer deep penetration depths into tissue for catheter based ablation treatments. In spectroscopy, fiber broadband lasers in the so-called atmospheric transmission windows from ~1.5-1.8µm and ~2-2.5µm, where losses during propagation are minimal, are particularly attractive for long distance applications like remote sensing that require light sources with high average power, good beam quality and output stability.
This thesis demonstrates fiber based infrared lasers and devices for applications in medicine, spectroscopy and metrology. For medical applications, we focus on single wavelength lasers utilizing their selectivity and/or penetration depth to target sebaceous glands in human skin, as a potential treatment for acne. The results of in vitro and in vivo laser renal denervation using a designed catheter are presented next, as a possible treatment option for hypertension with potentially faster treatment times and less arterial damage compared to existing techniques. For spectroscopy and metrology applications, we present the development of high power all-fiber broadband short wave IR(1.5-2.5µm) supercontinuum lasers, demonstrate system scalability in terms of power, spectrum, beam quality and output stability and show some of their potential applications in remote sensing and surface roughness measurements.

Sponsored by

Mohammed N. Islam