PHOTOREFRACTIVE EFFECTSPetr Tišer

Vedoucí projektu: Ing. Petr Hříbek, CSc.;

RNDr. Milan Durchan, CSc.

Petr Tišer

Photorefractive effects

26.7.2011

Project leaders: Ing.Petr Hříbek,CSc., RNDr. Milan Durchan CSc.

Motivation

High resolution imaging by photorefractive effect

– photorefractive microscope

Content

1. Stability of the table

2. Photorefractive effect

3. Light propagation in the photorefractive materials – BaTiO3 photorefractive mirror

4. Non-aberation imaging

5. Photorefractive microscope

6. Conclusion

Michelson interferometer He-Ne laser (λ = 632.8nm)

Interference fringe pattern

Table sensitivity – interference picture of sound

Snap fingers Frequency 1,738 kHz

Photorefractive material BaTiO3

Photosensitive material (generation of electrons)

Photoconductive material (electrons and holes conductivity)

Electro-optical material (refraction index change by the electric field)

Trapping of the electrons

fInterference field

Origin of the photorefractive effect

BaTiO3 photorefractive mirror

Non-aberation imaging

Difraction pattern in BaTiO3

1.2.

3.

Reflection of He-Ne beam in BaTiO3

0 1000 2000 3000 4000 5000 60000.00E+00

2.00E-06

4.00E-06

6.00E-06

8.00E-06

1.00E-05

1.20E-05

1.40E-05

1.60E-05

1.80E-05

Time (s)

Po

we

r(W

)

Photorefractive microscope

Test

Memory of a crystal1. 2.

2.

100 μm

Crystal of a protein

Crystal of salt

30 μm

Crystals of salt

30 μm

Onion cells

30 μm

Conclusion

Vibration isolation of the table High stability table (Michelson

interferometer) BaTiO3 photorefractive mirror Photorefractive microscope design and

creation

Thanks for attention