Ultra-fast pulsed lasers - more than just a light show
09 August 2012
DARPA is inviting partners to develop ultra-fast laser applications, from laser-driven secondary radiation generation to attosecond science.
A Navy ship at sea is surrounded by water, with nothing but its carrier group in site, and searches the skies for activity overhead. Isolated radars on each ship in the group scan independently of each other with limited effectiveness.
But consider if all of the ships’ radars could be coherently linked to function as one. Such a capability would improve the range and resolution of each radar system, making it possible to identify and characterise objects further away and with greater fidelity.
Conventional X-ray machines provide images of bones and organs that help doctors make crucial decisions regarding patient care. They cannot, however, resolve structures at the cellular level. Imagine having access to a table-top x-ray imager that could not only image a single cell, but also the nucleus, ribosomes and other components that make it up; and not only as a flat image, but in 3D. Such information would be invaluable for testing responses to candidate drugs and discovering new treatments.
These two very different applications are not science fiction and could be enabled by the same basic technology: ultra-fast, pulsed lasers operating at optical wavelengths.
These kinds of pulsed lasers are known as frequency combs because they are composed of thousands of individual laser lines, equally separated in frequency like the teeth of a comb. DARPA seeks to control the entire electromagnetic spectrum by using frequency combs to generate and engineer waves in the optical domain and then down or up-convert those waveforms to the desired wavelength.
Such technology has many potential defence applications, such as low phase noise microwave oscillators for secure communications, explosive and chemical agent detection, and the production of attosecond (10-18s) pulses for imaging the motion of electrons in complex materials.
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