1. Date of download: 6/3/2016 Copyright © 2016 SPIE. All rights reserved. Sample images, taken with a 5-in.-diameter f/12 telescope, are shown of the return from three cats-eye retroreflectors at a range of 16km, to illustrate the effect of aperture averaging. Figure Legend: From: Interference effects and aperture averaging in retroreflected light Opt. Eng. 2008;47(4):046002-046002-9. doi:10.1117/1.2911029

2. Date of download: 6/3/2016 Copyright © 2016 SPIE. All rights reserved. The scintillation index is plotted on a logarithmic scale for a pair of 6-mm-diameter retroreflectors as a function of their separation about the beam center. Also shown is the calculated number of fringes projected across the 50-mm-diameter receiver aperture as a function of the spacing of a pair of retroreflectors. The 500-m range was entirely over water with winds of 3.6kn, an air temperature of 22.5°C, and a water temperature of 27.7°C. Figure Legend: From: Interference effects and aperture averaging in retroreflected light Opt. Eng. 2008;47(4):046002-046002-9. doi:10.1117/1.2911029

3. Date of download: 6/3/2016 Copyright © 2016 SPIE. All rights reserved. (a) The scintillation index is plotted for a pair of 6-mm-diameter retroreflectors as a function of their separation at a range of 800m. Also shown is the scintillation index due to a single 6-mm-diameter retroreflector at the corresponding radial position as the second retroreflector is blocked. Weather conditions included winds of 4.5kn, an air temperature of 22.9°C, and a water temperature of 26°C. (b) The scintillation index is plotted for a pair of 10-mm-diameter retroreflectors as a function of their separation at a range of 800m. Also shown is the scintillation index due to a single 10-mm-diameter retroreflector at the corresponding radial position as the second retroreflector is blocked. Weather conditions included winds of 3.4kn, an air temperature of 22.1°C, and a water temperature of 25.7°C. (c) The scintillation index is plotted for a pair of 10-mm-diameter retroreflectors as a function of their separation at a range of 850m. Also shown is the scintillation index due to a single 10-mm-diameter retroreflector at the corresponding radial position when the second retroreflector is blocked. This range was entirely over land, but under benign weather conditions. Figure Legend: From: Interference effects and aperture averaging in retroreflected light Opt. Eng. 2008;47(4):046002-046002-9. doi:10.1117/1.2911029

4. Date of download: 6/3/2016 Copyright © 2016 SPIE. All rights reserved. The scintillation index of the returned power is shown as a function of the number of 16-mm-diameter cat’s-eye retroreflectors exposed at a range of 16km. Also shown is the scintillation index measured when the cat’s-eyes were covered and a single 3-in.- diameter corner-cube retroreflector was exposed in the center of the array. Data recorded on November 17, 2006. The scintillation index measured between Chesapeake Beach and Tilghman Island using the one-way adjacent link, at this same time, was 0.8. The value of Cn2 was inferred from angle-of-arrival measurements to be 1.6×10−15, corresponding to a value of the Rytov variance σ12=5.14. Figure Legend: From: Interference effects and aperture averaging in retroreflected light Opt. Eng. 2008;47(4):046002-046002-9. doi:10.1117/1.2911029

5. Date of download: 6/3/2016 Copyright © 2016 SPIE. All rights reserved. The scintillation index of the returned power is shown as a function of the number of 16-mm-diameter cat’s-eye retroreflectors exposed at a range of 16km. (a) Data recorded on October 18, 2006: The scintillation index for the one-way adjacent link, at this same time, was 0.55, while the value of Cn2 was 3×10−15, corresponding to a value of the Rytov variance σ12=9.6. (b) Data recorded on October 25, 2006: The scintillation index for the one-way adjacent link, at this same time, was 1.68, while the value of Cn2 was 1.5×10−14, corresponding to a value of the Rytov variance σ12=48. (c) Data recorded on November 27, 2006: the scintillation index for the one-way adjacent link, at this same time, was 1.05, while the value of Cn2 was 3×10−15, corresponding to a value of the Rytov variance σ12=9.6. Figure Legend: From: Interference effects and aperture averaging in retroreflected light Opt. Eng. 2008;47(4):046002-046002-9. doi:10.1117/1.2911029

6. Date of download: 6/3/2016 Copyright © 2016 SPIE. All rights reserved. The probability distribution function is shown in (a) to (d) for a pair of 10-mm-diameter retroreflectors with center-to-center spacings of 1.7, 2.5, 7.6, and 15cm, respectively, symmetrically placed about the optic axis at a range of 800m. The probability distribution function due to a single 10-mm-diameter retroreflector placed at the center of the illuminating beam, together with a best-fit lognormal profile, is shown in (e). Figure Legend: From: Interference effects and aperture averaging in retroreflected light Opt. Eng. 2008;47(4):046002-046002-9. doi:10.1117/1.2911029

7. Date of download: 6/3/2016 Copyright © 2016 SPIE. All rights reserved. The simulated probability distribution function is shown for a signal received by a 50-mm-diameter receiver, from a pair of point retroreflectors at a given spacing of 20mm at a range of 800m, for three random intensity distributions typical in low-scintillation conditions, equivalent to those of the experiments discussed here. Figure Legend: From: Interference effects and aperture averaging in retroreflected light Opt. Eng. 2008;47(4):046002-046002-9. doi:10.1117/1.2911029

8. Date of download: 6/3/2016 Copyright © 2016 SPIE. All rights reserved. The simulated probability distribution function is shown for signals received by a 50-mm-diameter receiver, from a pair of point retroreflectors at spacings of 15, 20, 25, and 35mm at a range of 800m, for a random intensity distribution characterized by μ=1, σ=0.01. Figure Legend: From: Interference effects and aperture averaging in retroreflected light Opt. Eng. 2008;47(4):046002-046002-9. doi:10.1117/1.2911029

9. Date of download: 6/3/2016 Copyright © 2016 SPIE. All rights reserved. The number of fades per second is shown for signals received by a 50-mm-diameter receiver from a pair of 10-mm-diameter retroreflectors with spacings of 15, 25, and 200mm at a range of 800m. Also shown is the corresponding fade rate for a single retroreflector. Figure Legend: From: Interference effects and aperture averaging in retroreflected light Opt. Eng. 2008;47(4):046002-046002-9. doi:10.1117/1.2911029

10. Date of download: 6/3/2016 Copyright © 2016 SPIE. All rights reserved. The fade duration is shown for signals received by a 50-nm-diameter receiver from a pair of 10-nm-diameter retroreflectors with spacings of 15, 25, and 200mm at a range of 800m. Also shown is the corresponding fade rate for a single retroreflector. Figure Legend: From: Interference effects and aperture averaging in retroreflected light Opt. Eng. 2008;47(4):046002-046002-9. doi:10.1117/1.2911029