Photonic orbital angular momentum in starlight^⋆

Further analysis of the 2011 Starfire Optical Range Observations

¹ Leidos, Albuquerque New Mexico, USA
e-mail: denis.w.oesch@leidos.com
² Air Force Research Laboratory, Directed Energy Directorate, Kirtland AFB, New Mexico, USA

Received: 27 November 2013
Accepted: 8 June 2014

Abstract

Context. Each attempt by the Atmospheric Simulation and Adaptive-optics Laboratory Testbed (ASALT) research group to detect turbulence-induced photonic orbital angular momentum (POAM) has been successful, spanning laboratory, simulation and field experiments, with the possible exception of the 2011 Starfire Optical Range (SOR) astronomical observations, a search for POAM induced by astronomical sources.

Aims. The purposes of this work are to discuss how POAM from astronomical turbulent assemblages of molecules or atoms (TAMA) would appear in observations and then to reanalyze the data from the 2011 SOR observations using a more refined technique as a demonstration of POAM in starlight.

Methods. This work uses the method of projections used previously in analysis of terrestrial data.

Results. Using the method of projections, the noise floor of the system was reevaluated and is found to be no greater than 1%. Reevaluation of the 2011 SOR observations reveals that a POAM signal is evident in all of the data.

Conclusions. POAM signals have been found in every instance of extended propagation through turbulence conducted by the ASALT research group, including the 2011 SOR observations. POAM is an inevitable result of the propagation of optical waves through turbulence.