ECE-1466 Modern Optics Course Notes Part 10

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ECE-1466Modern OpticsCourse NotesPart 10

• Prof. Charles A. DiMarzio
• Northeastern University
• Spring 2002

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Lecture Overview

• Two-Photon Mathematical Analysis
• Classical
• Electron on a Spring
• Non-Linear Response
• Quantum
• Second-Order Perturbation
• Virtual State
• Spatial and Temporal Issues

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Classical Description
a
(Electron as a Mass on a Spring)
a
v
x
v
x
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Energy Level Diagrams
Fluorescence
2-photon
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Mathematical Model

• Oversimplification, but useful for understanding
• Poisson Distribution
• Mean Number
• Probability of a Pair
• Time Interval
• Virtual State Lifetime

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Calculations

• Mean Number of Fluorescence Photons
• Mean Rate
• Defines d 2-Photon cross-section in m4sec
• Typical Value
• For 1/10 Photon per 100fs (laser pulse interval)

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Power Requirement

• Photon Irradiance
• Irradance
• Diffraction-Limited Area (1 square micrometer)
• Average Power at 100MHz, 100 fs width

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Spatial and Temporal Issues

• Focus the Light
• High Irradiance
• Depth-Slicing
• Resolution Sharpening
• Make the Pulse Short
• Low Duty Cycle
• Less Damage
• High Peak Power
• Stronger Signals

E2
E
E2A
PEA
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Course Summary
Diffraction
Radiometry
Polarization
Geometric Optics
NL Optics
Interference
Applications