A device is provided. The device includes a first lens assembly controllable to switch between a first plurality of optical powers. The first lens assembly includes a plurality of directly optically coupled lenses, and is configured to converge or diverge a light transmitted therethrough. The device also includes a second lens assembly coupled with the first lens assembly, and controllable to switch between a second plurality of optical powers that are opposite to the first plurality of optical powers.

The present invention describes a liquid crystal composite tunable device for fast polarisation-independent modulation of an incident light beam comprising: (a) two supporting and functional panels, at least one of them coated with a transparent conductive electrode layer and with optionally at least one additional layer selected from an alignment layer, antireflective coating layer, thermochromic or electrochromic layer, photoconductive or photosensitive layer, and (b) a composite structure sandwiched between said two panels and made of a liquid crystal and porous microparticles infiltrated with said liquid crystal. The porous microparticles have an average refractive index approximately equals to one of the liquid crystal principal refractive indices, matching that of the liquid crystal at one orientational state (for example, parallel n.sub.∥), and exhibiting large mismatch at another orientational state (for example, perpendicular n.sub.⊥). This refractive index mismatch between said microparticles and said liquid crystal is tuned by applying an external electric or magnetic field, thermally or optically.

An electrically switchable optical modulator for modulating an optical wavefront transmitted therethrough, comprising a birefringent first optical element and a birefringent second optical element each having respective ordinary and extraordinary refractive indices. A birefringent liquid crystal material is sandwiched between the first and second optical elements. The extraordinary refractive index of the liquid crystal material is electrically switchable between: a first state in which it has a first value; and, a second state in which it has a second value different from the first value. One or both of the first value and the second value is un-matched to the extraordinary refractive index of the first optical element in respect of light polarised in a first direction of linear polarisation, and is un-matched to the extraordinary refractive index of the second optical element in respect of light polarised in a second direction of linear polarisation orthogonal to the first direction. This switchably renders a relative contrast in extraordinary refractive index as between the liquid crystal material and the first and second optical elements for modulating said wavefront.

The present invention describes a liquid crystal composite tuneable device for fast polarisation-independent modulation of an incident light beam comprising: (a) two supporting and functional panels, at least one of them coated with a transparent conductive electrode layer and with optionally at least one additional layer selected from an alignment layer, antireflective coating layer, thermochromic or electrochromic layer, photoconductive or photosensitive layer, and (b) a composite structure sandwiched between said two panels and made of a liquid crystal and porous microparticles infiltrated with said liquid crystal. The porous microparticles have an average refractive index approximately equals to one of the liquid crystal principal refractive indices, matching that of the liquid crystal at one orientational state (for example, parallel n.sub.∥), and exhibiting large mismatch at another orientational state (for example, perpendicular n.sub.⊥). This refractive index mismatch between said microparticles and said liquid crystal is tuned by applying an external electric or magnetic field, thermally or optically.

Embodiments described herein relate to nanostructured trans-reflective filters having sub-wavelength dimensions. In one embodiment, the trans-reflective filter includes a film stack that transmits a filtered light within a range of wavelengths and reflects light not within the first range of wavelengths. The film stack includes a first metal film disposed on a substrate having a first thickness, a first dielectric film disposed on the first metal film having a second thickness, a second metal film disposed on the first dielectric film having a third thickness, and a second dielectric film disposed on the second metal film having a fourth thickness.

In various embodiments, a beam-parameter adjustment system and focusing system alters a spatial power distribution of a radiation beams before the beam is coupled into an optical fiber or delivered to a workpiece.

We describe a multimode reconfigurable optical spatial mode multiplexing system having first and second first and second input beams and a beam combiner to combine these into an optical output. At least one of the paths comprises a polarisation-independent reconfigurable phase modulator to impose a controllable phase profile on an input beam in an input beam phase modulating optical path, to controllably convert a spatial mode order of the input beam from a lower to a higher order spatial mode. The system also has a control input to control the phase modulator to configure the phase profile for the mode conversion. The input beams are combined into a multiple spatial mode combined beam output independent of a polarisation of the input beams. The number of spatial modes of the combined beam can be more than a number of spatial modes in either of the first and second input beams separately.

Nonreciprocal optical transmission devices and optical apparatuses including the nonreciprocal optical transmission devices are provided. A nonreciprocal optical transmission device includes an optical input portion, an optical output portion, and an intermediate connecting portion interposed between the optical input portion and the optical output portion, and comprising optical waveguides. A complex refractive index of any one or any combination of the optical waveguides changes between the optical input portion and the optical output portion, and a transmission direction of light through the nonreciprocal optical transmission device is controlled by a change in the complex refractive index.

Provided is a liquid crystal element. The liquid crystal element includes a first substrate, a first electrode provided on the first substrate, a liquid crystal layer provided on the first electrode and including a liquid crystal portion and a hydrophobic portion, and a second electrode on the liquid crystal layer, wherein the hydrophobic portion is phase-separated from the liquid crystal portion, wherein the liquid crystal portion includes polymer materials, a first dye, and liquid crystal molecules dispersed in the polymer materials, wherein the hydrophobic portion is spaced apart from the first electrode, wherein the hydrophobic portion includes hydrophobic materials and a second dye, wherein the first dye is dissolved in the polymer materials, wherein the second dye is dissolved in the hydrophobic portion, wherein the polymer materials include photo-curable polymer materials.

The present invention discloses a PIOS with a high extinction ratio based on slab PhCs which comprises an upper slab PhC and a lower slab PhC connected as a whole; the upper slab PhC is a first square-lattice slab PhC, the unit cell of the first square-lattice slab PhC includes a high-refractive-index rotating square pillar, a single first flat dielectric pillar and a background dielectric; the first flat dielectric pillar includes a high-refractive-index dielectric pipe and a low-refractive-index dielectric, or a high-refractive-index flat films, or a low-refractive-index dielectric; the lower slab PhC is a second square-lattice slab PhC with a complete bandgap, the unit cell of said second square-lattice slab PhC includes a high-refractive-index rotating square pillar, a single second flat dielectric pillar and a background dielectric is a low-refractive-index dielectric; and an normalized frequency of the optical switch is 0.41 to 0.4167.