Hyperspectral imaging systems are currently used for numerous activities related to spectral identification of
materials. These passive imaging systems rely on naturally reflected/emitted radiation as the source of the
signal. Thermal infrared systems measure radiation emitted from objects in the scene. As such, they can
operate at both day and night. However, visible through shortwave infrared systems measure solar illumination
reflected from objects. As a result, their use is limited to daytime applications. Omni Sciences has produced
high powered broadband shortwave infrared super-continuum laser illuminators. A 64-watt breadboard system
was recently packaged and tested at Wright-Patterson Air Force Base to gauge beam quality and to serve as a
proof-of-concept for potential use as an illuminator for a hyperspectral receiver. The laser illuminator was placed
in a tower and directed along a 1.4km slant path to various target materials with reflected radiation measured
with both a broadband camera and a hyperspectral imaging system to gauge performance.
A Mid-InfraRed FIber Laser (MIRFIL) has been developed that generates super-continuum covering the spectral range
from 0.8 to 4.5 microns with a time-averaged power as high as 10.5W. The MIRFIL is an all-fiber integrated laser with
no moving parts and no mode-locked lasers that uses commercial off-the-shelf parts and leverages the mature
telecom/fiber optics platform. The MIRFIL power can be easily scaled by changing the repetition rate and modifying
the erbium-doped fiber amplifier. Some of the applications using the super-continuum laser will be described in defense,
homeland security and healthcare. For example, the MIRFIL is being applied to a catheter-based medical diagnostic
system to detect vulnerable plaque, which is responsible for most heart attacks resulting from hardening-of-the-arteries
or atherosclerosis. More generally, the MIRFIL can be a platform for selective ablation of lipids without damaging
normal protein or smooth muscle tissue.
A principal challenge facing nanotechnology is consistently producing well-defined features much smaller than the wavelength of visible light. We find that the remarkably sharp threshold for femtosecond laser-induced material damage enables nanomachining with unprecedented precision and versatility, allowing highly reproducible machining of structures with nanoscale features. Using this methodology, we demonstrate, in glass, surface trenches that are only tens of nanometers in width but micron in depth, sub-surface channels that are hundreds nanometers in diameter, tens of microns deep, and hundreds microns in length, and 3D microstructures such as cantilevers. Furthermore, we demonstrate reproducible nanometer scale features in mixed and amorphous materials that differ significantly from glass, such as gold and onion cells. This technique is versatile, not material specific, and has potentially broad applications for MEMS construction and design, high density microelectronics, nanofluidics, material science, and optical memory.