Distribution A AFOSR Portfolio Review ASALT Lab Measurement

Distribution A AFOSR Portfolio Review -- ASALT Lab Measurement of Turbulence-induced POAM 5 November 2014 Dr. Darryl Sanchez (PI) Mr. Pat Kelly (PM) Directed Energy Directorate Air Force Research Laboratory Distribution A

Distribution A Outline • • Background -- review of POAM Review of Previous Results PAOM in Astrophysics POAM in Terrestrial Data Distribution A 2

Distribution A Photonic Orbital Angular Momentum intensity coherence wavelength • (Jackson, 1975) Angular momentum • (Allen, 1992) OAM is carried by L-G beams polarization • orbital angular momentum (POAM) • (van Enk, 1994) proper angular momentum operators, J = S + L • • • L-G beam can be created from H-G beams using cylindrical lenses S = spin angular momentum = circular polarization L = orbital angular momentum (Chen, 2008) Gauge invariance (non-local) • Jackson JD, "Classical Electrodynamics", 2 nd ed, 1975 • Allen L, Phys. Rev. Lett. (1992) • van Enk SJ, Euro. Phys. Lett. (1994), van Enk SJ, J. Mod. Phys. (1994) • Chen XS, Phys. Rev. Lett. (2008) Distribution A 3

Distribution A Turbulence-induced POAM - 1 Near Zenith point source Longer atmospheric paths Higher Cn 2 With longer atmospheric paths and higher Cn 2, POAM appears in the beam Atmosphere Observatory • Fried DL, JOSA A, (1992) • Sanchez DJ, Optics Express, (2011) Distribution A 4

Distribution A Turbulence-induced POAM - 2 Optical vortex trails are definitive proof of the presence of POAM in a traveling wave The Helicity Spectrum Projections of the Helicity Spectrum Identification of Optical Vortices Trajectories of the triplets t • C encloses a single branch point at (x k, yk) • mk is the helicity of that branch point x y Projections of the Helicity Spectrum Construction of the Helicity Spectrum Projections of the helicity spectrum capture the trajectories of the triples The triplets, (mk, xk, yk), fully describe the POAM component of the beam • Oesch DW, Optics Express (2010) • Sanchez DJ, Optics Express (2011 a) • Sanchez DJ, Optics Express (2011 b) Sloping trails in proj(H) definitively identify POAM • Oesch DW, Optics Express (2012 a) • Oesch DW, Optics Express (2012 b) • Oesch DW, Optical Eng (2012) Distribution A • Oesch DW, Optics Express (2013) • Sanchez DJ, A&A (2013) • Oesch DW, A&A (2014) 5

Distribution A Outline • • Background -- review of POAM Review of Previous Results POAM in Astrophysics POAM in Terrestrial Data Distribution A 6

Distribution A Creation Pairs & the Natural Geometry of TI-POAM Creation Pairs Creation Pair • follow directly from causality ==> Branch points are created Ø infinitesimally close together Ø in pairs of opposite helicity The Natural Geometry of Turbulence-induced POAM Creation Pairs in Simulation • Sanchez DJ, Opt Exp (2011) • Sanchez DJ, SPIE (2009) The Natural Geometry Distribution A Experimental Data 7

Distribution A Summary of Previous ASALT Results Velocity Turbulence-induced POAM in Traveling Waves t Persistence/Creation Pairs x Number of Layers y Strength and Distance SD Covariance • • • Oesch DW, Optics Express (2012 b) Oesch DW, Optics Express (2012 a) Oesch DW, OSA FIO (2012) Sanchez DJ, Optics Express (2011 b) Sanchez DJ, Optics Express (2011 a) Sanchez DJ, SPIE (2009) • Oesch DW, Opt Eng (2012) • Oesch DW, SPIE (2009) • Oesch DW, SPIE (2010) • Oesch DW, OSA Fi. O (2011) • Oesch DW, SPIE (2010) • Brennan TJ, OSA pc. DVT (2014) Distribution A 8

Distribution A Outline • • Background Review of Previous Results POAM in Astrophysics POAM in Terrestrial Data Distribution A 9

Distribution A 2011 Observation of Astronomical POAM HR 1529 HR 1577 Astronomical TAMA exhibit the same characteristics as Earth’s atmosphere PIGs in the ORION nebula HR 1895 • 3. 5 m telescope at Starfire Optical Range, Kirtland AFB • 24 x 24 Shack-Hartmann wavefront sensor • open loop frame rate = 2 KHz • l = 450 -650 nm • duration = 10 sec or 20 sec Distribution A HR 1784 49 Ceti 10

Distribution A POAM in the cosmos First ever measurement of POAM in the cosmos • SOR 3. 5 m telescope • 5 stars, 10 datasets • DW Oesch, et al. , Opt. Express, 21(5), 2013. • DJ Sanchez, et al, A&A, 556(A 130), 2013. • DW Oesch and DJ Sanchez, A&A, 2014. mean Ns 49 Ceti 0. 06 6 HR 1529 0. 07 5 0. 06 6 0. 04 5 0. 03 5 0. 04 5 0. 03 4 0. 17 9 0. 05 6 0. 04 6 HR 1577 HR 1784 Estimation of POAM via [[G]] HR 1895 Estimation of POAM via eimf Estimation of POAM using H Distribution A h Star Name POAM has been found in every instance when propagating through extended turbulence 11

Distribution A Outline • • Background Review of Previous Results POAM in Astrophysics POAM in Terrestrial Data -- the RACHL experiment Distribution A 12

Distribution A The RACHL Experiment Description • • 3. 2 Km path across a valley He. Ne laser as the source data collection on 22 days morning to mid-day (mostly) • Meade 40 cm telescope • Shack-Hartmann WFS • • 32 x 32 subapertures (d=2 cm) 18 x 18 pixels/subap SORTS instrument Distribution A 13

Distribution A The RACHL Experiment From Spots to Params Spots Standard parameters, r 0, s. I 2, f. G, D(t) Slopes ASALT lab parameters, r, H Hx and Hy (BP trails) Phase covariance (racetrack mode) Correlations • Brennan TJ, SPIE (2010) • Farrell TC, SPIE (2012) • Brennan TJ, OSA pc. DVT (2013) • Farrell TC, OSA pc. DVT (2013) • Oesch DW, Optics Express (2013) Distribution A • Brennan TJ, OSA pc. DVT (2014) • Farrell TC, OSA pc. DVT (2014) 14

Distribution A The RACHL Experiment Test Conditions Fried Parameter Scintillation Index Inner Scale BP density Anisotropy Brennan Coefficient (Rytov Parameter) Distribution A 15

Distribution A The RACHL Experiment Test Conditions Fried Parameter Scintillation Index (Rytov Parameter) BP density Inner Scale Anisotropy Distribution A 16

Distribution A The RACHL Experiment Instantaneous Correlation (Sample) r and r 0 Instantaneous Anti-correlation Fried parameter Optical Vortex density Distribution A 17

Distribution A The RACHL Experiment POAM in the beam - 1 The device can measure r=0 Fried parameter Optical Vortex density Projxt{H} Projyt{H} Distribution A 18

Distribution A The RACHL Experiment POAM in the beam - 2 Trails on 24 July 2014 at 11: 38: 43 Fried parameter Optical Vortex density Projxt{H} Projyt{H} Distribution A 19

Distribution A The RACHL Experiment POAM in the beam - 3 Trails on 24 July 2014 at 11: 38: 43 Fried parameter Optical Vortex density Projxt{H} Projyt{H} Distribution A 20

Distribution A The RACHL Experiment POAM in the beam - 4 Trails on 24 Jul 2014 11: 38: 43 Projxt{H} Projyt{H} Trails on 7 Aug 2014 10: 55: 16 Projxt{H} Projyt{H} Distribution A 21

Distribution A The RACHL Experiment POAM in the beam - 5 Trails on 2 Sept 2014 at 10: 27: 30 Projxt{H} Projyt{H} Trails on 4 Sept 2014 at 12: 16: 47 Projxt{H} Projyt{H} Distribution A 22

Distribution A The RACHL Experiment Future Publications Covariance of SD phase Correlation of Parameters Distribution A Functional Dependence 23

Distribution A Summary • • POAM is a recently discovered 5 th property of light • • We have measured POAM from astronomical sources Turbulence creates POAM is seen in great quantities in the RACHL data Distribution A 24

Distribution A Questions? The Starfire Optical Range Summer 2011 Distribution A 25