Light field

About: Light field is a research topic. Over the lifetime, 5357 publications have been published within this topic receiving 87424 citations.

Interfacing light and single atoms with a lens

Abstract: We characterize the interaction between a single atom or similar microscopic system and a light field via the scattering ratio. For this, we first derive the electrical field in a strongly focused Gaussian light beam, and then consider the atomic response. Following the simple scattering model, the fraction of scattered optical power for a weak coherent probe field leads to unphysical scattering ratios above 1 in the strong focusing regime. A refined model considering interference between the exciting and scattered field into finite-sized detectors or optical fibers is presented, and compared with experimental extinction measurements for various focusing strengths.

Coherent amplification and noise in gain-enhanced nanoplasmonic metamaterials: a Maxwell-Bloch Langevin approach.

Abstract: Nanoplasmonic metamaterials are an exciting new class of engineered media that promise a range of important applications, such as subwavelength focusing, cloaking, and slowing/stopping of light. At optical frequencies, using gain to overcome potentially not insignificant losses has recently emerged as a viable solution to ultra-low-loss operation that may lead to next-generation active metamaterials. Maxwell-Bloch models for active nanoplasmonic metamaterials are able to describe the coherent spatiotemporal and nonlinear gain-plasmon dynamics. Here, we extend the Maxwell-Bloch theory to a Maxwell-Bloch Langevin approach-a spatially resolved model that describes the light field and noise dynamics in gain-enhanced nanoplasmonic structures. Using the example of an optically pumped nanofishnet metamaterial with an embedded laser dye (four-level) medium exhibiting a negative refractive index, we demonstrate the transition from loss-compensation to amplification and to nanolasing. We observe ultrafast relaxation oscillations of the bright negative-index mode with frequencies just below the THz regime. The influence of noise on mode competition and the onset and magnitude of the relaxation oscillations is elucidated, and the dynamics and spectra of the emitted light indicate that coherent amplification and lasing are maintained even in the presence of noise and amplified spontaneous emission.

Deterministic creation of entangled atom-light Schr\"odinger-cat states

Abstract: Quantum physics allows for entanglement between microscopic and macroscopic objects, described by discrete and continuous variables, respectively. As in Schrodinger's famous cat gedanken experiment, a box enclosing the objects can keep the entanglement alive. For applications in quantum information processing, however, it is essential to access the objects and manipulate them with suitable quantum tools. Here we reach this goal and deterministically generate entangled light-matter states by reflecting a coherent light pulse with up to four photons on average from an optical cavity containing one atom. The quantum light propagates freely and reaches a remote receiver for quantum state tomography. We produce a plethora of quantum states and observe negative-valued Wigner functions, a characteristic sign of non-classicality. As a first application, we demonstrate a quantum-logic gate between an atom and a light pulse, with the photonic qubit encoded in the phase of the light field.

Apparatus and method for capturing digital images

Abstract: An apparatus and method for capturing digital images are provided. The digital capturing apparatus includes an image pickup unit obtaining light field data to change a view of a captured image and refocus the captured image, and a data processor generating a refocusing image using the light field data, wherein the image pickup unit performs optical modulation on light beams to obtain light field data of the modulated light beams so that the light beams are identified when two or more of the light beams overlap, and the data processor demodulates the light field data to obtain light field data of the light beams not subjected to the optical modulation.

Illumination system of a microlithographic projection exposure apparatus

Abstract: An illumination system of a microlithographic projection exposure apparatus includes a light source to produce projection light beam, and a first and a second diffractive optical element between the light source and a pupil plane of the illumination system. The diffractive effect produced by each diffractive optical element depends on the position of a light field that is irradiated by the projection light on the diffractive optical elements. A displacement mechanism changes the mutual spatial arrangement of the diffractive optical elements. In at least one of the mutual spatial arrangements, which can be obtained with the help of the displacement mechanism, the light field extends both over the first and the second diffractive optical element. This makes it possible to produce in a simple manner continuously variable illumination settings.