The present disclosure provides an optical waveguide design of a fiber modified with a thin layer of epsilon-near-zero (ENZ) material. The design results in an excitation of a highly confined waveguide mode in the fiber near the wavelength where permittivity of thin layer approaches zero. Due to the high field confinement within thin layer, the ENZ mode can be characterized by a peak in modal loss of the hybrid waveguide. Results show that such in-fiber excitation of ENZ mode is due to the coupling of the guided fundamental core mode to the thin-film ENZ mode. The phase matching wavelength, where the coupling takes place, varies depending on the refractive index of the constituents. These ENZ nanostructured optical fibers have many potential applications, for example, in ENZ nonlinear and magneto-optics, as in-fiber wavelength-dependent filters, and as subwavelength fluid channel for optical and bio-photonic sensing.

Devices and systems for opto-acoustic signal processing are described herein. In one embodiment, the device may include a structure configured to laterally confine travelling acoustic phonons (hypersound) throughout, a first multimode optical waveguide embedded within the structure, and an acoustic phonon emitter within the structure, where the first multimode optical waveguide is selected to couple to the acoustic phonons (hypersound) confined within the structure. In one embodiment, the system may include a first light source optically coupled to a proximal end of the first multimode optical waveguide, the first light source emitting a probe wave having a frequency ω.sub.p.sup.(1), and a driver configured to drive the acoustic phonon emitter to emit acoustic phonons (hypersound).

It is provided a method for producing a polarization converter The method comprising the following steps: producing a first converter element which has a base side, an upper side extending parallel to the base side, and a longitudinal side oriented obliquely at an angle ε.sub.1 to the base side or a curved longitudinal side; producing a second converter element which has a base side, an upper side extending parallel to the base side, and a longitudinal side oriented obliquely at an angle ε.sub.2 to the base side or a curved longitudinal side; arranging the first and the second converter element in series in such a way that the obliquely oriented or curved longitudinal sides point in opposite directions.

A higher-order mode (HOM) fiber is configured as a polarization-maintaining fiber by including a pair of stress rods at a location within the cladding layer that provides for a sufficient degree of birefringence without unduly comprising the spatial mode profile of the propagating higher-order modes. An optical imaging system utilizing polarization-maintaining HOM fiber allows for different wavelength probe signals to be directed into different modes, useful in applications such as STED microscopy, 2D sensing, and the like.

The invention offers high resolution and accuracy for nanoscale temperature mapping. Instead of collecting light after emission in near-field that decays to far-field, the present invention directly couples the near-field waves to a polaritonic-coated infrared probe. The polaritonic coating can be formed on an IR-tuned optical fiber to receive the coupled IR radiation and form polaritons, including plasmons or phonons, using the IR polaritonic material. The IR polaritons propagate along the probe decay back into the fiber core without substantial losses to far-field and are transmitted to a detector, such as a spectroscope. The coupling of the near-field energy to emission detected through the tip apex of fiber can be expressed as emission spectra. Through mapping with other spatial points, multi-dimensional displays and other information can be provided. The resolution can be less than 100 nanometers, such as at least an order of magnitude less than 100 nanometers.

A method fabricates an optical device that includes at least one partially reflecting surface and a light-wave transmitting substrate is fabricated. A plurality of transparent plates is obtained. At least one surface of at least one of the transparent plates is coated with a partially reflecting coating to form the at least one partially reflecting surface. The plates are arranged in a stack and attached to each other. The plates at the opposing ends of the stack are thicker than the remaining plates in the stack. The stack is sliced to form the substrate such that the substrate has two major external surfaces. The substrate is grinded or polished, and at least one of the two major external surfaces is coated with a coating that compensates for non-uniformity of the substrate.

An optical device has a first optical layer with a first dispersion response as a first function of wavelength. A second optical layer has a second dispersion response as a function of wavelength that is different than the first function. A separating layer is located between the first and second optical layers and has a lower refractive index than the first layer and the second layer. A thickness of the separating layer is selected such that the first and second dispersion responses combine to create an anomalous dispersion about a target wavelength. The anomalous dispersion results in the optical device emitting a wideband coherent optical output about the target wavelength in response to an optical input at the target wavelength.

An optical device includes a spatial light modulator and an optical waveguide with a plurality of extraction features. The plurality of extraction features is positioned relative to the optical waveguide so that a respective extraction feature receives light, having propagated within the optical waveguide, in a first direction and directs a first portion of the light in a second direction distinct from the first direction to exit the optical waveguide and illuminate at least a portion of the spatial light modulator. The plurality of extraction features is also positioned relative to the optical waveguide so that a respective extraction feature directs a second portion, distinct from the first portion, of the light to undergo total internal reflection, thereby continuing to propagate within the optical waveguide.

Structures for a polarizer and methods of forming a structure for a polarizer. A first slotted waveguide component is positioned over a first waveguide core, and a second slotted waveguide component positioned over the first slotted waveguide component. The first slotted waveguide component includes a second waveguide core and a third waveguide core separated by a first slot, and the second slotted waveguide component includes a fourth waveguide core and a fifth waveguide core separated by a second slot. The first waveguide core is laterally aligned with the first slot and the second slot.

A single-ended output circulator includes a three-core optical fiber head having first, second, and third optical fiber cores; a walk-off crystal having a first surface facing towards the second end of the three-core optical fiber head tube and a second surface facing away from the second end of the three-core optical fiber head tube; a plurality of half-wave plates each having a first surface coupled to the second surface of the walk-off crystal and a second surface facing away from the second surface of the walk-off crystal; a collimating lens having a first end and a second end; a reflection mirror configured to reflect light beams from the collimating lens; an optical prism between the collimating lens and the reflection mirror and configured to transmit a light beam along a propagation direction according to a polarization direction of the light beam; and a polarization rotator.