Polarized Polariton Fields on the Poincaré Sphere
Polarized Polariton Fields on the Poincaré Sphere
The state of polarization of light can be represented on the so-called Poincaré sphere, which provides a graphic representation of the Stokes parameters [1]. The circular-right polarization R corresponds to the north pole of the sphere and the circular-left polarization L to the south pole. The other cardinal points define the diagonal D, antidiagonal A, horizontal H, and vertical V polarizations. The Poincaré sphere can be used to track the state of polarization in a variety of contexts, such as spatial variations [2].
This Demonstration addresses the case of temporal variation. It shows the evolution in time of the polarization of light emitted by superimposing polariton fields, that is, from the light-matter interaction (Rabi coupling) in a semiconductor microcavity. It was recently proposed theoretically, and demonstrated experimentally [3], that such systems can afford a largely tunable spanning of the Poincaré sphere, depending on the parameters of two pulses exciting the system to create the state
ψ=⊗⊗⊗
α
R
i
θ
α
R
e
β
R
i
θ
β
R
e
α
L
i+ϕa
θ
α
L
e
β
L
i+ϕa
θ
β
L
e
t=0
This Demonstration lets you tune these parameters as well as the system parameters (Rabi frequency , polariton lifetime ) and track the state of polarization in time. Without decay (), the polarization describes a green circle, whereas with decay (), the polarization drifts around the sphere to converge to an asymptotic value, pointed to by the red arrow; the blue line shows the polarization trajectory between these two points, which can be tracked in time with the purple arrow.
g
γ
γ=0
γ≠0