In the name of God

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In the name of God

• Photonic crystals created
• by holography
• Raheleh Mohammadpour

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Photonic crystals

• Photonic crystals are microstructured materials
• which have periodic dielectric constant .

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Photonic Band Gap
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Comparison

• Semiconductors
• Energy band gaps
• Periodic crystal potential
• Atomic length scales
• Control electron flow

• Photonic crystals
• Photonic band gaps
• Periodic dielectric constant
• Length scale
• Control wave propagation

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Experimental setup
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Holographic lithography
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Intensity Pattern

• G mn(m,n0,,3) are
• reciprocal lattice vectors.

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Holographic lithography

• ?? The light is bright
• in the polymer make
• that part insoluble.
• In the dark regions
• of the interference
• pattern the polymer
• remain unchanged.

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3-D photonic crystal

• The structure of polymer atoms connected by
  polymer bonds and surrounded by air voids.

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1-D Photonic crystal

• 1-D photonic crystal (grating) formed by laser
• holography

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2-D photonic crystal

• 2-D photonic crystal fabricated by laser
• holography

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Consequence

• The holographic technique has the
• advantage of speed since the entire pattern
• in the photoresist is created in nanosecond.
• A variety of crystal structures can be
• created by varying the orientation and
• polarization of the beam lasers.