Application of Classical Beams of Orbital Angular Momentum
Radiation

The recognition in the early 1990s that light beams could possess Orbital Angular
Momentum (OAM) as well as spin angular momentum (polarization) has led to a flurry
of both experimental and theoretic research activity. The result has been a remarkable
series of technical advances that now enable the routine generation, manipulation and
measurement of intense beams of light possessing well-defined and well-controlled OAM
characteristics. A number of early experiments involving so-called optical spanners
demonstrated that classical OAM light beams could rotate microscopic particles, thus
conclusively showing such beams possess OAM. The successful measurement of single
photon OAM in 2002 resulted in a strong theoretical research focus on the novel quantum
mechanical properties of such photons. Besides the aforementioned optical spanners and
high information-density communication, the preponderance of experimental work is also
now squarely in the few-photon domain. While it is well known that the spin of a single
photon is quantized (σ = ± h), this property is seldom needed or exploited
by the defense
signal processing practitioners. Rather, the vast majority of defense applications occur
firmly in the classical limit where only the statistical ensembles of extremely large
numbers of photons are meaningful. Our presentation extends this analogy by identifying
a broad collection of tactical defense sensor and signal processing problems where
classical OAM photon beams may offer unique solutions.

Joint work with A. D. Greentree and W. Moran, Melbourne.

Joint work with A. D. Greentree and W. Moran, Melbourne.