Electromagnetically Induced Transparency(EIT)

Presenter:B. Younessi

Bonab University

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Overview

• Introduction• The history of EIT• The Physics of EIT• Some EIT-related phenomena

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Introduction

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A weak probe normally experiences absorption shown in blue. A second coupling beam induces EIT and creates a "window" in the absorption region (red).

Electromagnetically induced transparency is a technique for eliminating the effect of medium on a propagating beam of electromagnetic radiation.

The history of EIT

• The Physical effect that is the essence of EIT is called coherent population trapping which was discovered in 1976 by Gerardo Alzetta and his coworkers at University of Pisa in Italy

• Population trapping introduced and shown by Olga Kocharovskaya and Yakov Khanin at the Kalinin Leningrad Polytechnic institute in 1986

• EIT introduced in 1990 and experimentally observed in 1991 by Steve Harris

(Atac Imamoglu, K. Boller, Marlan Scully, … have also played important roles in developing EIT)

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The Physics of EIT

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The Physics of EIT(Physical and Optical Properties of Rubidium 87 )

From Quantum mechanics we have J= L+SL: orbital angular momentumS: spin angular momentum

The hyperfine structure is a result of the coupling of J with the total nuclear angular momentum I. The total atomic angular momentum F is then given by F=J+II: total nuclear angular momentum

The magnitude of F can take the values

For the 87Rb ground state, J = 1/2 and I = 3/2, so F = 1 or F = 2.

For the ground state in 87Rb, L = 0 and S = 1/2, so J = 1/2; for the first excited state, L = 1, so J = 1/2 or J = 3/2 the L=0 L=1 (D line) transition is split into two components; the D1 line and the D2 line

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The Physics of EIT(Physical and Optical Properties of Rubidium 87 )

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The total Hamiltonian can be written as After having introduced the dipole approximation as well as

the rotating wave approximation, the interaction Hamiltonian can be represented in a rotating frame by

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The Physics of EIT(Static description of EIT)

The eigenvalues of the interaction Hamiltonian can be calculated to

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The Physics of EIT(Static description of EIT)

It is straightforward to verify that the corresponding eigenstates of the interaction Hamiltonian are

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The Physics of EIT(Static description of EIT)

If

The Physics of EIT(The origin of EIT)

The ground state becomes identical to the dark state from

which excitation cannot occur

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This results in EIT

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The Physics of EIT(Dynamic description of EIT)

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The Physics of EIT(Dynamic description of EIT)

Master Equation

Polarization

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The Physics of EIT(Density matrix solution)

By applying perturbation theory

Off-diagonal density-matrix

elements

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The Physics of EIT(The linear susceptibility)

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The Physics of EIT(EIT)

For two-photon Raman resonance( )

and ( ) both both real and imaginary parts of the linear susceptibility vanish.

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EIT-related phenomena (Slow light)

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EIT-related phenomena (Light storage)

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EIT-related phenomena (Experimental setup)

Thanks for your attention and patience!

Any questions ?