Photon Switching by

1
Photon Switching by Quantum Interference
??? ???????
2
Transition Diagram
3
The Three-Fold Entangled State
where 1 or 0 in the  ?s,  ?p, and  ?f denotes
presence or absence of the switching, probe, and
fluorescence photons measured by the detectors.
Requirements OD ? 10 and ? ? 10-3?.
4
Frequency Spectrum
Wc 1.5 G Ws 1.5 G
Thin and thick lines are the spectra of probe
absorption without and with the switching field,
respectively.
5
Steady-State Properties at the Resonance
where OD is the optical density defined by Iout
Iin e-OD and TD is the propagation delay time.
For ?s ? ?p, large OD(0,0) and negligible ? are
the requirements to satisfy both EIT and PS
conditions.
6
Perturbation Method
7
One Photon per ?2 Switches the Medium from
Transparency to Opacity
8
Rise Time of the Probe Absorption
9
Transient Behaviors of the Probe Absorption
10
Defects in the Current Calculation
?in(t)
?(t)
?out(t)
11
The More Precise Calculation
Probe propagation
Switching propagation
Atomic coherence
?
12
Pulse Propagation in the EIT Medium
For N 0,
In general, solve the following equations
numerically.
13
Slice Sample and Neglect Propagation Delay
However, Im?31/? can diverge.
14
Treat ??/?t Term as Perturbation
. . . . . .
Find the analytical solution of ?31(?p(x,t)) and
numerically solve the equation of probe
propagation.
Wc 0.1 and Wp,max 0.052.