Abstract: In certain embodiments, an optical device and a method of use is provided. The optical device includes a fiber Bragg grating having a substantially periodic refractive index modulation along a length of the fiber Bragg grating. The fiber Bragg grating has a power transmission spectrum with a plurality of local transmission minima, wherein each pair of neighboring local transmission minima has a local transmission maximum therebetween. The local transmission maximum has a maximum power at a transmission peak wavelength. The optical device further includes a narrowband optical source in optical communication with a first optical path and a second optical path.

Abstract: Electromagnetic energy transfer is facilitated. In accordance with an example embodiment, a first resonator transmits electromagnetic energy using an electromagnetic wave, based on frequency matching and alignment of an electromagnetic field with a second resonator within a distance of one wavelength of the electromagnetic wave from the first resonator. An electromagnetic energy reflector adjacent the first resonator redirects reflected portions of the electromagnetic wave back towards the first resonator.

Abstract: An optical device, a method of configuring an optical device, and a method of using a fiber Bragg grating is provided. The optical device includes a fiber Bragg grating, a narrowband optical source, and at least one optical detector. The fiber Bragg grating has a power transmission spectrum as a function of wavelength with one or more resonance peaks, each comprising a local maximum and two non-zero-slope regions with the local maximum therebetween. The light generated by the narrowband optical source has a wavelength at a non-zero-slope region of a resonance peak that is selected such that one or more of the following quantities, evaluated at the resonance peak, is at a maximum value: (a) the product of the group delay spectrum and the power transmission spectrum and (b) the product of the group delay spectrum and one minus the power reflection spectrum.

Abstract: Aspects of the present disclosure are directed to providing and/or controlling electromagnetic radiation. As may be implemented in accordance with one or more embodiments, an apparatus includes a first structure that contains an object, and a second structure that is transparent at solar wavelengths and emissive in the atmospheric electromagnetic radiation transparency window. The second structure operates with the first structure to pass light into the first structure for illuminating the object, and to radiatively cool the object while preserving the object's color.

Abstract: An optical device, a method of configuring an optical device, and a method of using a fiber Bragg grating is provided. The optical device includes a fiber Bragg grating, a narrowband optical source, and at least one optical detector. The fiber Bragg grating has a power transmission spectrum as a function of wavelength with one or more resonance peaks, each comprising a local maximum and two non-zero-slope regions with the local maximum therebetween. The light generated by the narrowband optical source has a wavelength at a non-zero-slope region of a resonance peak that is selected such that one or more of the following quantities, evaluated at the resonance peak, is at a maximum value: (a) the product of the group delay spectrum and the power transmission spectrum and (b) the product of the group delay spectrum and one minus the power reflection spectrum.

Abstract: In certain embodiments, an optical device and a method of use is provided. The optical device includes a fiber Bragg grating having a substantially periodic refractive index modulation along a length of the fiber Bragg grating. The fiber Bragg grating has a power transmission spectrum with a plurality of local transmission minima, wherein each pair of neighboring local transmission minima has a local transmission maximum therebetween. The local transmission maximum has a maximum power at a transmission peak wavelength. The optical device further includes a narrowband optical source in optical communication with a first optical path and a second optical path.

Abstract: The first and second media are coupled via evanescent waves generated by surface phonon polaritons thermally excited on surfaces of the first and second media. First and second media made of the same material are disposed with a gap formed between for cutting off thermal conduction and the heat transfer between them is performed via the thermally excited evanescent waves. A third medium is provided on a surface of the first medium on a side toward the second medium. Heat flux flows from the second medium to the first medium in a first state wherein the second medium has a first temperature TH and the first medium has a second temperature TL lower than the TH differ in intensity from heat flux which flows from the first to the second medium in a second state wherein the first medium has the TH and the second medium has the TL.

Abstract: An optical device includes a hollow-core photonic-bandgap fiber, wherein at least a portion of the hollow-core photonic-bandgap fiber is adjustably axially twisted.

Abstract: A system and method for reducing coherent backscattering-induced errors in an optical gyroscope is provided. A first time-dependent phase modulation is applied to a first laser signal and a second phase modulation is applied to a second laser signal. The phase-modulated first laser signal propagates in a first direction through a waveguide coil and the phase-modulated second laser signal propagates in a second direction opposite the first direction through the waveguide coil. The first time-dependent phase modulation is applied to the phase-modulated second laser signal after the phase-modulated second laser signal propagates through the waveguide coil to produce a twice-phase-modulated second laser signal. The second time-dependent phase modulation is applied to the phase-modulated first laser signal after the phase-modulated first laser signal propagates through the waveguide coil to produce a twice-phase-modulated first laser signal.

Abstract: An optoelectronic device comprising an optically active layer that includes a plurality of domes is presented. The plurality of domes is arrayed in two dimensions having a periodicity in each dimension that is less than or comparable with the shortest wavelength in a spectral range of interest. By virtue of the plurality of domes, the optoelectronic device achieves high performance. A solar cell having high energy-conversion efficiency, improved absorption over the spectral range of interest, and an improved acceptance angle is presented as an exemplary device.

Abstract: An optical device and a method of using an optical filter are provided. The optical device includes an optical filter and a narrowband optical source. The optical filter has a refractive index that varies along a length of the optical filter. The narrowband optical source is in optical communication with the optical filter and is configured to generate light having a wavelength at or in the vicinity of at least one of a wavelength corresponding to a local transmission maximum and a wavelength corresponding to a maximum slop of the group index spectrum of the optical filter.

Abstract: In certain embodiments, an optical device and a method of use is provided. The optical device can include a fiber Bragg grating and a narrowband optical source. The narrowband optical source can be configured to generate light. A first portion of light can be transmitted along a first optical path extending along and through the length of the fiber Bragg grating at a group velocity. The light can have a wavelength at or in the vicinity of a wavelength at which one or more of the following quantities is at a maximum value: (a) the product of the group index spectrum and a square root of the power transmission spectrum, (b) the slope of a product of the group index spectrum and one minus the power transmission spectrum, and (c) the slope of a product of the group index spectrum and the power transmission spectrum.

Abstract: Various aspects as described herein are directed to a radiative cooling device and method for cooling an object. As consistent with one or more embodiments, a radiative cooling device includes a solar spectrum reflecting structure configured and arranged to suppress light modes, and a thermally-emissive structure configured and arranged to facilitate thermally-generated electromagnetic emissions from the object and in mid-infrared (IR) wavelengths.

Abstract: A method for detecting rotation includes providing a plurality of resonant waveguides generally adjacent to one another and optically coupled to one another. Each resonant waveguide of the plurality of resonant waveguides is configured to allow light to propagate along the resonant waveguide in a planar path. The method further includes propagating light along each path in a clockwise direction or along each path in a counterclockwise direction.

Abstract: In one embodiment of the present disclosure, a device is disclosed comprising a macroscopic thermal body and an extraction structure that is electromagnetically-coupled to the thermal emitting area of the thermal body. The macroscopic thermal body having a thermal emitting area, and the extraction structure configured and arranged to facilitate emission from, or receipt to the thermal emitting area that exceeds a theoretical, Stefan-Boltzmann, emission limit for a blackbody having the same thermal emitting area as the thermal body.

Abstract: An optical sensor, a method of configuring an optical sensor, and a method of using an optical sensor are provided. The optical sensor includes an optical loop having a length and a laser source optically coupled to the loop. The laser source has a coherence length. Light from the source is transmitted to the loop as a first signal and a second signal counterpropagating along the loop. The optical paths of the first signal and the second signal are substantially reciprocal with one another and the first signal and the second signal are combined together after counterpropagating through the loop to generate a third signal. A ratio of the coherence length to the length of the loop is greater than 1.

Abstract: The refractive index of the at least one photonic structure having two separate photonic bands is modulated, so that light supplied to the at least one photonic structure and initially in one of the two photonic bands of the traveling along a forward direction in the at least one photonic structure is converted to light in a second one of the photonic bands, and light in the one photonic band traveling along a backward direction opposite to the forward direction in the at least one photonic structure is not converted and remains in the one photonic band, achieving non-reciprocity.

Abstract: An optical sensor, a method of configuring an optical sensor, and a method of using an optical sensor are provided. The optical sensor includes an optical waveguide having a length and a laser source optically coupled to the waveguide. The laser source has a coherence length. Light from the source is transmitted to the waveguide as a first signal propagating along the waveguide in a first direction and a second signal propagating along the waveguide in a second direction opposite to the first direction. The optical paths of the first signal and the second signal are substantially reciprocal with one another and the first signal and the second signal are combined together after propagating through the waveguide to generate a third signal. The coherence length is greater than 1 meter or is in a range between 200 microns and 10 centimeters.

Abstract: An optical fiber includes a cladding with a material having a first refractive index and a pattern of regions formed therein. Each of the regions has a second refractive index lower than the first refractive index. The optical fiber further includes a core region and a core ring having an inner perimeter, an outer perimeter, and a thickness between the inner perimeter and the outer perimeter. The thickness is sized to reduce the number of ring surface modes supported by the core ring.

Abstract: A method for forming a substrate comprising nanometer-scale pillars or cones that project from the surface of the substrate is disclosed. The method enables control over physical characteristics of the projections including diameter, sidewall angle, and tip shape. The method further enables control over the arrangement of the projections including characteristics such as center-to-center spacing and separation distance.