NEW LASER SOURCES BENEFIT REMOTE SENSING
Many molecules exhibit strong absorptions at mid-infrared
(mid-IR) and terahertz (THz) wavelengths, which lie roughly between
3-30μm and 30μm-1mm, respectively. Applications for the mid-IR
include: standoff threat agent detection; environmental/safety
monitoring of greenhouse gases and pollutants; engine emissions
reduction; prospecting for oil and gas reserves; medical
diagnostics; and infrared countermeasures. Although metal and water
absorb THz light, many common materials, drugs, explosives,
biochemical agents, and living tissues are semi-transparent at THz
wavelengths. THz light also provides sub-millimeter spatial
resolution for imaging and, unlike x-rays, is non-ionizing. These
unique properties are driving an array of THz applications: these
include security checks of people, mail, or luggage; cancer
detection; and non-destructive testing.
The utility of mid-IR and THz wavelengths has spurred the
development of various methods to generate laser light in these
spectral regions. For widespread implementation, however, no device
thus far has appeared to have an optimal mix of properties: high
brightness, for sensitivity and range; wide wavelength coverage,
for use with many substances; small size, for portability;
room-temperature operation, for practical convenience and low power
consumption; and low-enough cost.
With a unique blend of: high peak and average power; high
spatial and spectral brightness; wide tuning range; sealed,
maintenance-free operation; and shoebox size; M Squared's Firefly-IR and Firefly-THz laser
sources are opening the door to practical implementations of
laser-based remote sensing.