Page 5, Fried's Coherence Length

Table of Contents

• Front Matter

• Introduction
• Conventional Adaptive Optics System

• Image Spread with Atmospheric Turbulence

• The Principle of Phase Conjugation

• Point Spread Function for an Astronomical Telescope

• Modeling the Effect of Atmospheric Turbulence
• Fried's Coherence Length

• Astronomical “Brightness”

• Isoplanatic Angle

• Zernike Polynomials

• Atmospheric Turbulence Models

• Coherence Length for Various Wavelengths and Turbulence Models

• Wind Models

• Kolmogorov Model

• Greenwood Frequency

• Angle of Arrival Fluctuations (Image Motion)

• Modulation Transfer Function

• Beam Propagation
• Laser “Brightness”

• The Strehl Ratio—Laser-Beam Propagation to the Far Field with Wavefront Error

• Strehl Ratio

• Spot Size for a Gaussian Beam

• Spot Size for a Uniform Circular Aperture

• System Performance Estimation
• System Performance Estimation

• Modal and Zonal Fitting Error

• Partial Correction

• Temporal Error

• Focal Anisoplanatism (the “Cone Effect”)

• Laser Guide Stars

• Scintillation

• Wavefront Sensors
• Wavefront Sensor Requirements

• Shack-Hartmann Wavefront Sensor and Error

• Lenslet Array Selection

• Shearing Interferometer Wavefront Sensor and Error

• Curvature Wavefront Sensor and Error

• Deformable Mirrors
• Tilt Mirror Requirements

• Deformable Mirror Requirements

• Deformable Mirror Actuator Configurations

• Actuator and Wavefront Sensor Layouts

• Actuators: Requirements for Zonal or Modal Control

• Deformable Mirror Influence Function Models

• Bimorph and MEMS Mirrors

• Segmented Deformable Mirrors

• Control and Reconstruction
• Adaptive Optics System Control Model

• Reconstructor

• Wavefront Control

• Influence Matrix

• Kalman Filtering and Wavefront Estimation

• Computational Latency

• Predictor

• Effect of Sampling Rate on Achievable Bandwidth

• Hartmann Sensing Software Implementation

• Appendix
• Equation Summary

• Back Matter