Nonlinear Optics

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Nonlinear Optics
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Nonlinear susceptibility tensor
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The Physical origin of optical nonlinearities
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Oscillator model
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Non-resonant nonlinearities
Second-order nonlinearities (?(2))
-- Nonlinear frequency mixing
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Phase matching
Optical frequency conversion (Second Harmonic
generation)
Energy conservation Momentum conservation
k
? ? ?2 - 2?1 0 ? k k2 -2k 1 0

Birefringence Phase Match (BPM)
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QPM Condition ?k(k2?-2k ?)-Gm0
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Overview of third-order phenomena
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• Frequency tripling

Phase match problem

• The optical Kerr effect and the nonlinear
  rafractive index
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  ( degeneate four-wave mixing)

No phase match problem
(K Kerr constant)
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• Stimulated Raman scattering

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Resonant nonlinearities
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Saturable absorber
Resonant nonlinerarities are third-order nonlinear
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Resonant nonlinearities in semiconductors
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Optical bistability