ECE 299 Holography and Coherent Imaging Lecture 1 Gabor Holography David J. Brady Duke University...

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ECE 299 Holography and Coherent Imaging

Lecture 1 Gabor Holography

David J. BradyDuke University

Lecture 1: Gabor Holography

www.disp.duke.edu/~dbrady/courses/holography

Outline

• Course objectives• What is holography?• Gabor holography• Modeling coherent fields• Simulation of Gabor holograms

Lecture 1: Gabor Holography

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Course Context

• Holography and Coherent Imaging is part of a three course sequence in optical systems

• Courses may be taken in any order

Lecture 1: Gabor Holography

ECE 376 Optical Design

ECE 375 Optical Imaging and Spectroscopy

Holography and Coherent Imaging

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Optical Systems

Lecture 1: Gabor Holography

• ECE 375 discusses systems with natural light illumination• Holography and Coherent Imaging discusses systems with laser illumination• ECE 376 considers optical components for either natural or laser illuminated systems

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Course Objectives

Students completing this course will be able to1. Layout analog and digital holographic recording systems2. Analyze sampling and resolution limits in holographic

systems3. Analyze the information capacity of holograms4. Analyze broadband hologram and OCT systems5. Design computer generated holograms6. Reconstruct images from holographically recorded data7. Analyze (and maybe reduce) speckle noise in coherent

images

Lecture 1: Gabor Holography

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What is holography?

• Holography is a method for measuring the electromagnetic “E” field using irradiance detectors.

• Holography is a type of “homodyne” interferometry• Analog holography relies on light induced changes

in the dielectric or transmissive properties of materials

• Digital holography relies on opto-electronic detection

Lecture 1: Gabor Holography

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Homodyne vs. Heterodyne Detection

Lecture 1: Gabor Holography

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Gabor Holography

Lecture 1: Gabor Holography

A New Microscopic PrincipleD. GABORNature 161, 777 - 778 (1948)

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Gabor Holography

Lecture 1: Gabor Holography

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Modeling Coherent Fields

Lecture 1: Gabor Holography

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Scattering

Lecture 1: Gabor Holography

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Scattering

Lecture 1: Gabor Holography

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Scattering

Limiting object to plane z=0,

Lecture 1: Gabor Holography

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Holographic Interferometry

Lecture 1: Gabor Holography

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Holographic Interferometry

For monochromatic fields, the integral over time is trivial and

Lecture 1: Gabor Holography

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Gabor Holography

Lecture 1: Gabor Holography

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Gabor Holography

Lecture 1: Gabor Holography

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Gabor Holography

Lecture 1: Gabor Holography

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Gabor Holography

Lecture 1: Gabor Holography

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What is the Fringe Frequency?

Lecture 1: Gabor Holography

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What is the Fringe Frequency?

Lecture 1: Gabor Holography

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What is the Fringe Frequency?

Lecture 1: Gabor Holography

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Modeling Gabor Holograms

Lecture 1: Gabor Holography

Distance in mm, 5.5 micron sampling period

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Modeling Gabor Holograms

Lecture 1: Gabor Holography

Diffracted 8 mm with 0.6 micron wavelength

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Modeling Gabor Holograms

Lecture 1: Gabor Holography

Diffracted 36 mm with 0.6 micron wavelength

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Model of Gabor’s Hologram

Lecture 1: Gabor Holography

Diffracted 14 mm with 0.6 micron wavelength

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Reconstruction

Lecture 1: Gabor Holography

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Hologram, reconstruction andpseudoscopic reconstruction at 7 mm range

Lecture 1: Gabor Holography

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How is this a microscope?

Lecture 1: Gabor Holography

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