1,504 research outputs found
Why you should not use the electric field to quantize in nonlinear optics
We show that using the electric field as a quantization variable in nonlinear
optics leads to incorrect expressions for the squeezing parameters in
spontaneous parametric down-conversion and conversion rates in frequency
conversion. This observation is related to the fact that if the electric field
is written as a linear combination of bosonic creation and annihilation
operators one cannot satisfy Maxwell's equations in a nonlinear dielectric.Comment: This version corrects a minor typo from the published version in
Optics Letters. Eq. 22 should have an \epsilon_0 that is lacking in the OL
versio
A Hamiltonian treatment of stimulated Brillouin scattering in nanoscale integrated waveguides
We present a multimode Hamiltonian formulation for the problem of
opto-acoustic interactions in optical waveguides. We establish a Hamiltonian
representation of the acoustic field and then introduce a full system with a
simple opto-acoustic coupling that includes both photoelastic/electrostrictive
and radiation pressure/moving boundary effects. The Heisenberg equations of
motion are used to obtain coupled mode equations for quantized envelope
operators for the optical and acoustic fields. We show that the coupling
coefficients obtained coincide with those established earlier, but our
formalism provides a much simpler demonstration of the connection between
radiation pressure and moving boundary effects than in previous work [C. Wolff
et al, Physical Review A 92, 013836 (2015)].Comment: 39 pages: 20 pages for main article + 19 pages supplementary
information; 3 figure
High efficiency in mode selective frequency conversion
Frequency conversion (FC) is an enabling process in many quantum information
protocols. Recently, it has been observed that upconversion efficiencies in
single-photon, mode-selective FC are limited to around 80%.In this letter we
argue that these limits can be understood as time-ordering corrections (TOCs)
that modify the joint conversion amplitude of the process. Furthermore we show,
using a simple scaling argument, that recently proposed cascaded FC protocols
that overcome the aforementioned limitations act as "attenuators" of the TOCs.
This observation allows us to argue that very similar cascaded architectures
can be used to attenuate TOCs in photon generation via spontaneous parametric
down-conversion. Finally, by using the Magnus expansion, we argue that the
TOCs, which are usually considered detrimental for FC efficiency, can also be
used to increase the efficiency of conversion in partially mode selective FC
Current injection by coherent one- and two-photon excitation in graphene and its bilayer
Coherent control of optically-injected carrier distributions in single and
bilayer graphene allows the injection of electrical currents. Using a
tight-binding model and Fermi's golden rule, we derive the carrier and
photocurrent densities achieved via interference of the quantum amplitudes for
two-photon absorption at a fundamental frequency, , and one-photon
absorption at the second harmonic, . Strong currents are injected
under co-circular and linear polarizations. In contrast, opposite-circular
polarization yields no net current. For single-layer graphene, the magnitude of
the current is unaffected by the rotation of linear-polarization axes, in
contrast with the bilayer and with conventional semiconductors. The dependence
of the photocurrent on the linear-polarization axes is a clear and measurable
signature of interlayer coupling in AB-stacked multilayer graphene. We also
find that single and bilayer graphene exhibit a strong, distinct
linear-circular dichroism in two-photon absorption.Comment: 9 pages, 8 figure
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