Search results for "Polar"
showing 10 items of 3817 documents
Surface Plasmons for Chiral Sensing
2021
Chiral sensitive techniques have been used to probe the fundamental symmetries of the universe, study biomolecular structures, and even develop safe drugs. The traditional method for the measurement of chirality is through optical activity, however, chiroptical signals are inherently weak and often suppressed by large backgrounds. Different techniques have been proposed to overcome the limitations of traditionally used optical polarimetry, such as cavity- and/or nanophotonic-based schemes. In this chapter we demonstrate how surface plasmon resonance can be employed as a new research tool for chiral sensing, which we term here as CHIral Surface Plasmon Resonance (CHISPR). We present how surf…
Dissipative soliton resonance in a passively mode-locked fiber laser
2011
The phenomenon of dissipative soliton resonance (DSR) predicts that an increase of pulse energy by orders of magnitude can be obtained in laser oscillators. Here, we prove that DSR is achievable in a realistic ring laser cavity using nonlinear polarization evolution as the mode-locking mechanism, whose nonlinear transmission function is adjusted through a set of waveplates and a passive polarizer. The governing model accounts explicitly for the arbitrary orientations of the waveplates and the polarizer, as well as the gain saturation in the amplifying medium. It is shown that DSR is achievable with realistic laser settings. Our findings provide an excellent design tool for optimizing the mo…
Cascade coherence transfer and magneto-optical resonances at 455 nm excitation of Cesium
2010
We present and experimental and theoretical study of nonlinear magneto-optical resonances observed in the fluorescence to the ground state from the 7P_{3/2} state of cesium, which was populated directly by laser radiation at 455 nm, and from the 6P_{1/2} and 6P_{3/2} states, which were populated via cascade transitions that started from the 7P_{3/2} state and passed through various intermediate states. The laser-induced fluorescence (LIF) was observed as the magnetic field was scanned through zero. Signals were recorded for the two orthogonal, linearly polarized components of the LIF. We compared the measured signals with the results of calculations from a model that was based on the optica…
Polarization instability in anisotropic-cavity degenerate four-wave mixing
2000
Abstract The emission and stability properties of a plane-wave model of intracavity degenerate four-wave mixing including self- and cross-phase modulation are studied. A Kerr medium inside an anisotropic cavity in which a linearly polarized field is injected is considered. Cavity anisotropy leads to qualitative new phenomena such as a subcritical polarization instability.
Spontaneous polarization induced by natural thermalization of incoherent light
2008
We analyze theoretically the polarization properties of a partially coherent optical field that propagates in a nonlinear Kerr medium. We consider the standard model of two resonantly coupled nonlinear Schrödinger equations, which account for a wave-vector mismatch between the orthogonal polarization components. We show that such a phase-mismatch is responsible for the existence of a spontaneous repolarization process of the partially incoherent optical field during its nonlinear propagation. The repolarization process is characterized by an irreversible evolution of the unpolarized beam towards a highly polarized state, without any loss of energy. This unexpected result contrasts with the …
Passive Polarimetric Imaging
2014
Passive electro-optical polarimetric imaging is a form of remote sensing in which the properties associated with electromagnetic field orientation are exploited as a means to discriminate between objects in an extended scene. The purpose of this chapter is to introduce some fundamental concepts in the science of imaging polarimetry. These concepts include the Stokes-Mueller description of polarized light, the physical mechanisms that contribute to polarimetric image contrast, a mathematical description of several polarimetric imaging systems, and an example target detection algorithm. Polarimetric image contrast is discussed in terms of reflected, emitted, and scattered light. Special empha…
Source of Polarized Electrons for MAMI B
1991
A source of polarized electrons has been set up in order to inject polarized electrons into the 855 MeV c.w. electron accelerator MAMI B at the Mainz nuclear physics institute. It is based on photoemission of the 3/5 semiconductor GaAsP and will provide a d.c. current of 100 µA with a beam emittance of 1π mm mrad, and a polarization of about 40%.
Momentum-space spectroscopy for advanced analysis of dielectric-loaded surface plasmon polariton coupled and bent waveguides
2013
We perform advanced radiation leakage microscopy of routing dielectric-loaded plasmonic waveguiding structures. By direct plane imaging and momentum-space spectroscopy, we analyze the energy transfer between coupled waveguides as a function of gap distance and reveal the momentum distribution of curved geometries. Specifically, we observed a clear degeneracy lift of the effective indices for strongly interacting waveguides in agreement with coupled-mode theory. We use momentum-space representations to discuss the effect of curvature on dielectric-loaded waveguides. The experimental images are successfully reproduced by a numerical and an analytical model of the mode propagating in a curved …
The optical system of the A4 laser Compton polarimeter
2007
Compton backscattering polarimeters for experiments at sub-mA accelerator facilities use optical cavities to increase the laser light intensity. Therefore, parasitic properties of the optical elements have an increased influence on the polarization state of the light and need to be analyzed carefully. This contribution shows examples of such difficulties and the possible solutions, found during the setup of the A4 Compton backscattering polarimeter at the MAMI accelerator facility of the university of Mainz.
Graphical representation of non-absorbing polarization devices
2000
A graphical representation of general non-absorbing polarization devices operating under normal plane-wave incidence is presented. The representation is based on a four-dimensional spherical parametrization of the Jones matrix of this kind of polarization devices. The graphical representation takes the form of a solid cylinder. The projection of the point representing the device over the base of the cylinder gives the corresponding polarization eigenvectors represented in the complex plane, while the height of the point in the cylinder is the phase of its eigenvalue. Some simple examples like wave-plates and rotators are discussed. The representation may represent a useful tool to identify …