30 Jan 2004
The US military’s research arm talks about its activities in photonics.
With the deputy director of DARPA [the Defense Advanced Research Projects Agency] speaking at this year’s OPTO plenary, it’s easy to understand why every seat in the Marriott’s ballroom was taken on Tuesday morning. And Robert Leheny certainly did not disappoint as he took listeners on a whirlwind tour of the organization's past, present and future plans in photonics.
The first thing to understand is that DARPA has a big wallet. For fiscal 2003, its total budget was a hefty $2.69 bn and this is forecast to top $3 bn by 2005. Leheny explained that DARPA is broken into eight divisions, of which six are involved in photonics. He said that optical technologies play a major role in many military applications, especially those relating to sensing and communications.
On his whistle-stop tour of current programs, Leheny highlighted the SUVOS project which falls under the umbrella of “Photonics for Sensing”. SUVOS stands for semiconductor ultraviolet optical sources and DARPA plans to develop both GaN and AlGaN sources that emit in the deep ultraviolet down to 280nm.
The idea is that the sources could be used to excite fluorescence signatures from a range of biological species. According to Leheny the long-term goal is to develop an efficient sensor and detector package that is the size of a smoke-detector.
DARPA is also involved in a project to develop an imaging coherent optical radar. This system is mounted on a vehicle which shakes the ground in front of it. A laser vibrometer studies the ground’s vibrations looking for suspicious objects such as landmines.
Under the title “Photonics for Actuation”, DARPA is looking into a hybrid RF and optical freespace link. When cloudy, such a link would ensure that data could still be sent using radio frequencies. However when the weather is clear, data can be sent over a broadband optical connection.
And finally, under the heading “Photonics Enabling Sciences”, DARPA is in the process of developing chip-scale atomic clocks. Leheny said that such devices would be around one cubic centimetre in size and contain a VCSEL that could be locked to a known atomic transition. He told delegates that this could potentially be a revolutionary technology as it would remove the need to rely on GPS systems.