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Space-time analogy True for all pulse/beam shapes Paraxial approximation (use of Fourier transforms) Gaussian beams (q parameters and matrices) Geometric optics?? a dimensionless a dimension of 1/v
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SPACE TIME Fourier transform in time Fourier transform in space
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e(-r/M) e(r) Space-time analogy Geometric optics d1 d2 SPACE
DIFFRACTION DIFFRACTION By matrices:
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e(--t/M) e(t) Space-time analogy Geometric optics d1 d2 TIME
DISPERSION DISPERSION By matrices: y length in time T = chirp imposed on the pulse
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e(-r/M) e(r) Space-time analogy Gaussian optics d1 d2 SPACE
DIFFRACTION DIFFRACTION By matrices:
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e(--t/M) e(t) Space-time analogy Gaussian optics d1 d2 TIME
DISPERSION DISPERSION By matrices: = chirp imposed on the pulse Find the image plane:
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WHAT IS THE MEANING k”d? Lf Fiber L Prism Lg b Gratings d Fabry-Perot at resonance
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e(-r/M) e(r) e(t) e1(t) TIME MICROSCOPE d1 d2 d2 d1 TIME LENS
DIFFRACTION DIFFRACTION e(t) d2 d1 DISPERSION e1(t) TIME LENS DISPERSION
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e1(t) e1(t)eiat ep(t) = eeiat w1 w1 + wp wp TIME LENS DISPERSED INPUT
OUTPUT w1 + wp e1(t)eiat 2 wp CHIRPED PUMP ep(t) = eeiat 2
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FEMTOSECOND COMMUNICATION:
Space-time analogy – application to fs communication FEMTOSECOND COMMUNICATION: Commercial fs lasers – a pulse duration of 50 fs. (20 THz) One can easily “squeeze” a 12 bit word in 1 ps
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Propagation of time- multiplexed signals Time compressor Time
EMITTER RECEIVER 1 ns 1 ns 1 ns 1 ns Time compressor Time stretcher time time, ps 4 3 2 1
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Time “telescope” (reducing)
Time “microscope” (expanding)
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e e e e e e e e e e e (a) (a) (b) (b) x x d d d d image image object
1 1 2 2 image image object object e ( r ) e e e ( - r/M ) e e ( ( ) ) ( ( - - r/M r/M ) ) r r (a) (a) diffraction diffraction diffraction diffraction e ( t ) e e ( ( t t ) ) e ( - t/M ) e ( - t/M ) TIME TIME LENS LENS (b) (b) dispersion dispersion dispersion dispersion
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