37 research outputs found
A scheme comparison of Autler-Townes based slow light in inhomogeneously broadened quantum dot media
We propose a method to achieve significant optical signal delays exploiting
the effect of Autler-Townes splitting in an inhomogeneously broadened quantum
dot medium. The absorption and slow-down effects are compared for three schemes
i.e. , V and , corresponding to different excitation
configurations. Qualitative differences of the V-scheme compared to the -
and -scheme are found, which show that features of Autler-Townes
splitting are only revealed in the V-scheme. The underlying physical mechanisms
causing this discrepancy are analyzed and discussed. Finally we compare field
propagation calculations of the schemes showing significantly larger achievable
signal delays for the V-scheme despite finite absorption of the coupling field.
This opens the possibility for using waveguide structures for both coupling and
probe fields, thus significantly increasing the achievable signal delays
Gender Bias in Nobel Prizes
Strikingly few Nobel laureates within medicine, natural and social sciences
are women. Although it is obvious that there are fewer women researchers within
these fields, does this gender ratio still fully account for the low number of
female Nobel laureates? We examine whether women are awarded the Nobel Prizes
less often than the gender ratio suggests. Based on historical data across four
scientific fields and a Bayesian hierarchical model, we quantify any possible
bias. The model reveals, with exceedingly large confidence, that indeed women
are strongly under-represented among Nobel laureates across all disciplines
examined
Gender bias in Nobel prizes
Abstract Strikingly few Nobel laureates within medicine, natural and social sciences are women. It is obvious that there are fewer women researchers within these fields, but does this still fully account for the low number of female Nobel laureates? We examine whether women are awarded the Nobel Prizes less often than the gender ratio suggests. Based on historical data across four scientific fields and a Bayesian hierarchical model, we quantify any possible bias. The model reveals, with exceedingly large confidence, that indeed women are strongly under-represented among Nobel laureates across all disciplines examined
Dispersion of guided modes in two-dimensional split ring lattices
We present a semi-analytical point-dipole method that uses Ewald lattice
summation to find the dispersion relation of guided plasmonic and bianisotropic
modes in metasurfaces composed of 2D periodic lattices of arbitrarily strongly
scattering magneto-electric dipole scatterers. This method takes into account
all retarded electrodynamic interactions as well as radiation damping
selfconsistently. As illustration we analyze the dispersion of plasmon nanorod
lattices, and of 2D split ring resonator lattices. Plasmon nanorod lattices
support transverse and longitudinal in-plane electric modes. Scatterers that
have an in-plane electric and out-of-plane magnetic polarizability, but without
intrinsic magnetoelectric coupling, result in two bands that are mixtures of
the bands of electric-only and magnetic-only lattices. Thereby bianisotropy
through mutual coupling, in absence of building-block bianisotropy, is evident.
Once strong bi-anisotropy is included in each building block, the Bloch modes
become even more strongly magnetoelectric. Our results are important to
understand spatial dispersion and bianisotropy of metasurface and metamaterial
designs
Nonlinear carrier dynamics in a quantum dash optical amplifier
Results of experimental pump-probe spectroscopy of a quantum dash optical
amplifier biased at transparency are presented. Using strong pump pulses we
observe a competition between free carrier absorption and two-photon induced
stimulated emission that can have drastic effects on the transmission dynamics.
Thus, both enhancement as well as suppression of the transmission can be
observed even when the amplifier is biased at transparency. A simple
theoretical model taking into account two-photon absorption and free carrier
absorption is presented that shows good agreement with the measurements