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Complementary Speckle Patterns: Deterministic Interchange of Intrinsic Vortices and Maxima through Scattering Media
Jérôme Gateau1, Hervé Rigneault2, Marc Guillon3
1Holographic Microscopy Group, Neurophotonics Laboratory, CNRS UMR 8250, Paris Descartes University, Sorbonne Paris Cité, 75006 Paris, France.
Physical Review Letters
|February 11, 2017
Summary
Researchers experimentally swapped speckle pattern intensity peaks and zeros using a spiral phase delay. This technique creates complementary speckle patterns, enhancing synthetic speckle grain size.
Area of Science:
- Optics and Photonics
- Wave Phenomena
- Speckle Pattern Analysis
Background:
- Speckle patterns are formed by the interference of coherent light scattered from a rough surface.
- The intensity distribution and extrema locations in speckle patterns are crucial for various applications.
- Controlling these features offers potential for advanced optical manipulation.
Purpose of the Study:
- To experimentally interchange intensity maxima and zeros in speckle patterns.
- To investigate the transformation of focused beams into vortex beams and vice versa.
- To characterize the statistical properties of the generated complementary speckle patterns.
Main Methods:
- Applying a spiral phase delay of charge ±1 to a coherent beam impinging on a diffuser.
- Experimental generation of complementary speckle patterns.
- Numerical simulations to analyze extrema statistics and intensity distribution.
Main Results:
- Successful experimental interchange of intensity maxima and zeros in speckle patterns.
- Demonstration that incoherent superposition of three complementary speckle patterns enlarges synthetic speckle grain size by a factor of sqrt[3].
- Observation of a cyclic permutation of optical vortices and intensity maxima.
Conclusions:
- The spiral phase delay effectively transforms focused beams into vortex beams and vice versa, altering speckle patterns.
- Complementary speckle patterns can be generated and manipulated.
- The superposition of these patterns offers a method for controlled enhancement of speckle grain size.
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