Search results for "Physics::Optics"
showing 10 items of 1958 documents
Space-time analogy for partially coherent plane-wave-type pulses.
2005
In this Letter we extend the well-known space-time duality to partially coherent wave fields and, as a limit case, to incoherent sources. We show that there is a general analogy between the paraxial diffraction of quasi-monochromatic beams of limited spatial coherence and the temporal distortion of partially coherent plane-wave pulses in parabolic dispersive media. Next, coherence-dependent effects in the propagation of Gaussian Schell-model pulses are retrieved from that of their spatial counterpart, the Gaussian Schell-model beam. Finally, the last result allows us to present a source linewidth analysis in an optical fiber communication system operating around the 1.55 microm wavelength w…
Debye representation of dispersive focused waves
2006
We report on a matrix-based diffraction integral that evaluates the focal field of any diffraction-limited axisymmetric complex system. This diffraction formula is a generalization of the Debye integral applied to apertured focused beams, which may be accommodated to broadband problems. Longitudinal chromatic aberration may limit the convenience of the Debye formulation and, additionally, spatial boundaries of validity around the focal point are provided. Fresnel number is reformulated in order to guarantee that the focal region is entirely into the region of validity of the Debye approximation when the Fresnel number of the focusing geometry largely exceeds unity. We have applied the matri…
Generation of accelerating beams using nano-scale metallic circular gratings
2014
Spatially accelerating beams that are solutions to the Maxwell equations may propagate along incomplete circular trajectories, after which diffraction broadening takes over and the beams spread out. In this paper we report on numerical simulations that show the conversion of a high-numerical-aperture focused beam into a nonparaxial shape-preserving accelerating beam having a beam-width near the diffraction limit. Beam shaping is induced by a diffractive optical element that consists of a non-planar sub-wavelength grating enabling a Bessel signature.
Tunable structured illumination system based on a Wollaston prism
2018
Experimental verification of a simple illumination system to generate a 1D structured pattern with tunable modulation frequency is shown based on a Wollaston prism illuminated by the diffracted field of an incoherent linear source.
Plasmon-driven nondiffracting surface beaming
2011
We introduce diffraction-free plasmonic waves in metal-dielectric surfaces which are the analogue to nondiffracting Bessel beams in free space. By interfering multiple converging plane waves with controlled phase matching, we generate a subwavelength transverse spot located at the boundaries of a 1D plasmonic lattice. The diffraction-free beam is resonantly transmitted through the stratiform medium leading not only to light confinement but also to wave enhancement assisted by surface plasmons polaritons. To conclude, we briefly analyze other types of localized surface modes which were proposed recently.
All-incoherent dispersion-compensated optical correlator
2007
We report on a simple, spatially incoherent, wavelength-independent imaging system that, in contrast to the conventional case, exhibits a dispersion-compensated point-spread function. Our hybrid (diffractive-refractive) three-lens imaging configuration thus acts as an all-incoherent dispersion-compensated optical irradiance correlator. So the optical arrangement is well adapted to processing color information (both spatially and temporally incoherent) under natural illumination.
Coherent control of stimulated emission inside one-dimensional photonic crystals
2004
In this paper, the quasinormal mode (QNM) theory is applied to discuss the quantum problem of an atom embedded inside a one-dimensional (1D) photonic band gap (PBG) cavity pumped by two counterpropagating laser beams. The e.m. field is quantized in terms of the QNMs in the 1D PBG and the atom modeled as a two-level system is assumed to be weakly coupled to just one of the QNMs. The main result of the paper is that the decay time depends on the position of the dipole inside the cavity, and can be controlled by the phase difference of the two laser beams.
Characterization of Hong-Ou-Mandel bunched states by quantum homodyne tomography
2014
We experimentally demonstrate quantum homodyne tomography of Hong-Ou-Mandel bunched states, which are created by dynamically adjusting emission timings of two heralded single photons using coupled cavities.
Electrodynamics in complex systems
1996
This paper discusses recent theoretical efforts to develop a general and flexible method for the calculation of the field distributions around and inside complex optical systems involving both dielectric and metallic materials. Starting from the usual light-matter coupling Hamiltonian, we derive a self-consistent equation for the optical field in arbitrary optical systems composed of N different subdomains. We show that an appropriate solving procedure based on the real-space discretization of each subdomain raises the present approach to the rank of an accurate predictive numerical scheme. In order to illustrate its applicability, we use this formalism to address challenging problems relat…
Influence of light polarization on the dynamics of optically pumped lasers.
1990
The dynamic behavior of a coherently pumped ring laser with a homogeneously broadened four-level medium is analyzed theoretically, considering linearly polarized pump and generated laser beams. The laser is shown to be much more stable when these polarizations are parallel than when they are orthogonal. In the latter case the instability pump threshold can be as low as four times the first laser threshold, and the laser dynamics shows Lorenz-type features.