LADAR resolution improvement using receivers enhanced with squeezed-vacuum injection and phase-sensitive amplification

Journal of the Optical Society of America B: Optical Physics

Volumn 27, Issue 6, 2010, Pages

  Dutton, Zachary ^a   Shapiro, Jeffrey H ^b   Guha, Saikat ^a  

^a BBN TECHNOLOGIES   (United States)

^b MASSACHUSETTS INSTITUTE OF TECHNOLOGY   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

AMPLIFICATION; OPTICAL RADAR; SIGNAL TO NOISE RATIO; VACUUM;

ENTRANCE PUPIL; ERROR RATE; FREE PHASE; FREQUENCY INFORMATION; HOMODYNE DETECTION; HOMODYNES; HYPOTHESIS TESTS; LASER DETECTION AND RANGING SYSTEMS; PHASE-SENSITIVE AMPLIFICATIONS; QUANTUM RESOURCES; RESOLUTION IMPROVEMENT; SPATIAL RESOLUTION;

ERROR DETECTION;

EID: 77955666181     PISSN: 07403224     EISSN: None     Source Type: Journal    
DOI: 10.1364/JOSAB.27.000A63     Document Type: Article

References (26)

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14. Strictly speaking, the soft aperture must be embedded inside a hard-aperture pupil, e.g., A----=e?2----2/R2 for-----D/2 and A----=0 otherwise. Without appreciable loss of generality we shall ignore that constraint here and in Section 3 because: (1) we are interested in soft apertures whose transmission at the hard-aperture limit is 1%; and (2) we will not be assuming so much SVI and PSA that the hardaperture limit will constrain the soft-aperture resolution improvement afforded by these quantum enhancements. We shall, however, impose the hard-aperture limit in Section 4, when we employ MTF analysis to generate simulated baseline and quantum-enhanced imagery.
15. One-to-one imaging corresponds to setting F=L in Fig. 1, a choice that simplifies the notation. In reality, of course, the target range will satisfy L-F, however, this merely introduces a minification factor into the analysis.
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17. This equal-strength assumption makes the LADAR's task of distinguishing between the one-target and two-target hypotheses entirely a matter of the spatial pattern in the image plane rather than detected target-return strength.
18. Strictly speaking,-T-x----1 is required. However, because of the quasi-Lambertian nature of the target reflection, the simple expressions we have provided lead to appropriate statistics for the classical target-return field arriving at the LADAR receiver's entrance pupil.
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21. Strictly speaking-/2 is the maximum value of
22. It is only because we are employing paraxial optics that 0? appears to be possible. In practice, however, we will never be concerned with angular separations that take us outside the realm of paraxial optics.
23. Our Gaussian soft-aperture definition for Rayleigh resolution is chosen so that the depth of the trough between the average photon-flux density of the two point targets on the detector array is equal to the trough depth present for the same two targets when they are imaged through an unobscured hard pupil of length D and they are separated by the hard-aperture Rayleigh angle 2 0=-/D.
24. Alternatively, for stationary targets, we can use a two-pulse illumination sequence, with the first pulse employed to image the real quadrature and the second pulse employed to image the imaginary quadrature, to achieve similar results.
25. Once again we are violating-T--1, and once again our field-reflection model does not pose a problem in that it gives physically reasonable statistics for the Fraunhoferdiffracted target return that is collected by the LADAR's entrance pupil.
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