Marcelo Martinelli
Instituto de Física, Universidade de
São Paulo, São Paulo, Brazil
My fair light: bright
multicolor entanglement
Entanglement between bright optical beams can be
generated quite simply from initially squeezed beams combined on
beamsplitters.
Yet, this approach is limited to single-frequency entangled light.
Direct
generation of entanglement, on the other hand, by means of nonlinear
processes,
can produce fields of different frequencies (or colors). This opens up
the
possibility of changing the color of quantum information and connecting
pieces
of quantum hardware which interact with light at different frequencies.
The
system we study is the above-threshold optical parametric oscillator.
Entanglement between the twin beams it produces was predicted in 1988,
but was only
experimentally verified in 2005, owing to the difficulty in measuring
phase
noise. Shortly after, we predicted that this simple and very well-known
system
should directly produce tripartite entanglement, between the bright
pump,
signal, and idler beams. In this talk, I will present our measurements
of twin beam
entanglement and also of bright three-color optical quantum
correlations, a
first step towards tripartite entanglement.