point spread function engineering for the advanced optics...
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ThoeryComputational Imaging
Lab
Point Spread Function Engineeringfor the Advanced Optics Lab
Tony Barsic
University of Colorado at BoulderDepartment of Electrical, Computer, and Energy Engineering
Dr. Piestun’s Research Groupanthony.barsic@colorado.edu
March 3rd, 2014
A. Barsic PSF Engineering 1
ThoeryComputational Imaging
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PSFMTF
Point Spread Function
I The response of an imaging system to a point source
I It’s the imaging version of the impulse response of a linearsystem.
I Assumptions:I linearI shift-invariant
A. Barsic PSF Engineering 2
ThoeryComputational Imaging
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PSFMTF
Modulation and Optical Transfer Function
A. Barsic PSF Engineering 3
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PSFMTF
Modulation
A. Barsic PSF Engineering 4
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DefocusComputational ImagingCubic PhaseDH-PSF
DefocusIs this the best we can do? Is the information lost forever?Can we recover more information?
Yes, with PSF Engineering. (a.k.a. ”wavefront coding.”)A. Barsic PSF Engineering 5
ThoeryComputational Imaging
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DefocusComputational ImagingCubic PhaseDH-PSF
Computational Imaging
A. Barsic PSF Engineering 6
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DefocusComputational ImagingCubic PhaseDH-PSF
Cubic Phase
A. Barsic PSF Engineering 7
ThoeryComputational Imaging
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DefocusComputational ImagingCubic PhaseDH-PSF
Cubic Phase
A. Barsic PSF Engineering 8
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DefocusComputational ImagingCubic PhaseDH-PSF
Double Helix PSF
A. Barsic PSF Engineering 9
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DefocusComputational ImagingCubic PhaseDH-PSF
Double Helix PSF
A. Barsic PSF Engineering 10
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4fset-upSLMPrelab Help
4f Imaging SystemThis is what you will actually be working with in lab (conceptually).
What can we do with this system? What do we see in the ”SLM”plane?
I Optical signal processing.I modulate phase? amplitude?I if we put, say, DH-PSF there, what has changed? Are we
getting more information? Why/how?A. Barsic PSF Engineering 11
ThoeryComputational Imaging
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4fset-upSLMPrelab Help
Lab Setup
This is the same idea, but folded up.
Why would we fold it? Why don’t we (researchers in Rafael’sgroup) actually fold it for experiments?
A. Barsic PSF Engineering 12
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4fset-upSLMPrelab Help
Spatial Light ModulatorThese are expensive.
I array of pixels (”spatial”)I vary phase delay (”light modulator”)
I Does this work with both polarizations?I What happens to the other pol.?I How to fix it? (3 ideas)
A. Barsic PSF Engineering 13
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4fset-upSLMPrelab Help
How to simulate PSF
Think about the 4f system.
I Put a pt source on axis in object plane
I How does shifting the pt source in the plane affect phase inthe pupil?
I axial shift?
A. Barsic PSF Engineering 14
ThoeryComputational Imaging
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4fset-upSLMPrelab Help
DH-PSF
You will generate a DH-PSF
I superposition of modes from the Gauss-Laguerre modal plane
I GL plane is just a way to describe patterns (similar to zernike)
I The prelab gives details
I write a matlab function that generates a GL mode
A. Barsic PSF Engineering 15
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