In the name of God

Photonic crystals created

by holography

Raheleh Mohammadpour

Photonic crystals

Photonic crystals are microstructured materials

which have periodic dielectric constant .

Photonic Band Gap

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

Experimental setup

Holographic lithography

Intensity Pattern

G mn(m,n=0,…,3) are

reciprocal lattice vectors.

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.

3-D photonic crystal

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

1-D Photonic crystal

1-D photonic crystal (grating) formed by laser

holography

2-D photonic crystal

2-D photonic crystal fabricated by laser

holography

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.