Flexible photonic crystal structures capable of changing color in response to strain are described. Methods for forming two-dimensional and three-dimensional flexible photonic crystal structures are described. In some aspects, the flexible photonic crystal structures include an array of holes or voids formed within a flexible material. The flexible material changes dimensions of the array when the flexible photonic crystal structures is stretched, pulled, pushed or bent. In some aspects, the flexible photonic crystal structures include an array of features made of a first material, such as a first type of polymer, embedded within a matrix material made of a second material, such as a second type of polymer. The flexible photonic crystal structures can be used in the manufacture of consumer products, such as electronic products, electronic product accessories, thin films, flexible displays and wearable products.

An example device includes a nanovoided polymer element, a first electrode, and a second electrode. The nanovoided polymer element may be located at least in part between the first electrode and the second electrode. In some examples, the nanovoided polymer element may include anisotropic voids. In some examples, anisotropic voids may be elongated along one or more directions. In some examples, the anisotropic voids are configured so that a polymer wall thickness between neighboring voids is generally uniform. Example devices may include a spatially addressable electroactive device, such as an actuator or a sensor, and/or may include an optical element. A nanovoided polymer layer may include one or more polymer components, such as an electroactive polymer.

A form birefringent optical element includes a structured layer and a dielectric environment disposed over the structured layer. At least one of the structured layer and the dielectric environment includes a nanovoided polymer, the nanovoided polymer having a first refractive index in an unactuated state and a second refractive index different than the first refractive index in an actuated state. Actuation of the nanovoided polymer can be used to reversibly control the form birefringence of the optical element. Various other apparatuses, systems, materials, and methods are also disclosed.

An optical element includes a nanovoided polymer layer having a first refractive index in an unactuated state and a second refractive index different than the first refractive index in an actuated state. Compression or expansion of the nanovoided polymer layer, for instance, can be used to reversibly control the size and shape of the nanovoids within the polymer layer and hence tune its refractive index over a range of values, e.g., during operation of the optical element. Various other apparatuses, systems, materials, and methods are also disclosed.

Examples include a device including a nanovoided polymer element having a first surface and a second surface, a first plurality of electrodes disposed on the first surface, a second plurality of electrodes disposed on the second surface, and a control circuit configured to apply an electrical potential between one or more of the first plurality of electrodes and one or more of the second plurality of electrodes to induce a physical deformation of the nanovoided polymer element.

An example device includes a nanovoided polymer element, which may be located at least in part between the electrodes. In some examples, the nanovoided polymer element may include anisotropic voids, including a gas, and separated from each other by polymer walls. The device may be an electroactive device, such as an actuator having a response time for a transition between actuation states. The gas may have a characteristic diffusion time (e.g., to diffuse half the mean wall thickness through the polymer walls) that is less than the response time. The nanovoids may be sufficiently small (e.g., below 1 micron in diameter or an analogous dimension), and/or the polymer walls may be sufficiently thin, such that the gas interchange between gas in the voids and gas absorbed by the polymer walls may occur faster than the response time, and in some examples, effectively instantaneously.

Apparatus include a photoelastic modulator (PEM) optical element, a controller having a frequency generator configured to produce a frequency signal at a selected frequency based on a clock signal of the controller wherein the controller is configured to produce a PEM driving signal based on the frequency signal, a PEM transducer coupled to the PEM optical element and the controller and configured to drive the PEM with the PEM driving signal, and a detector optically coupled to the PEM optical element and configured to receive a PEM modulated output and to produce a PEM detection signal that includes a PEM modulation signal, wherein the controller is configured to receive the PEM detection signal and to extract the PEM modulation signal from the PEM detection signal using the frequency signal and the clock signal.

A sky kaleidoscope system includes a polarizing film, a first plastic plate having a first transparent design, and a second plastic plate having a second transparent design. The polarizing film is sandwiched between the first plastic plate and the second plastic plate. The first and second transparent designs are photoelastic and/or light diffracting. The sky kaleidoscope may be held up to the sky and the plastic plates and polarizing film may be looked through to view resulting rainbow colors in the first or second transparent design.

The present application discloses a 3D imaging method and apparatus, which divide a source 3D image light into two polarized light beams carrying image information through a birefringence effect, adjust optical paths of the two polarized light beams obtained through birefringence, and control the two polarized light beams to be alternately irradiated, thereby achieving 3D imaging; since the implementation of the above imaging method only requires one imaging apparatus having corresponding functions, the present application can simplify the system structure and reduce the system cost relative to a conventional 3D projection technology that requires two imaging devices; moreover, a viewer can directly see, with no need to wear corresponding 3D glasses, a 3D image due to the parallax caused by alternate irradiation of two polarized light beams carrying image information out of a projection device.

The invention provides an elastomeric optical device having a first optical state and a second optical state. The device is transparent when in the first optical state and is translucent or opaque when in the second optical state. The device comprises, in sequence, an optional substrate, a first transparent electrode, an optional dielectric layer, an elastomer layer, and a second transparent electrode. In some embodiments, the second transparent electrode comprises an electrically-conductive polymer, transparent electrically-conductive nanoparticles, or both. In such embodiments, the second transparent electrode is configured to compress the elastomer layer in response to an electric field between the first and second transparent electrodes, such that when the elastomeric optical device is in the second optical state the elastomer layer is compressed between the first and second transparent electrodes. One or both of the elastomer layer and the second transparent electrode has one or more non-uniformity features.