A frequency converter system includes a source that emits a beam having a wide spectral band; and a frequency conversion cell including 1) a birefringent nonlinear crystal having a first phase-matching wavelength, with an input face that receives the beam, an output face that emits at least one frequency-converted beam, and at least two parallel faces different from the input and output faces; 2) means for applying an external mechanical force to at least one of said two parallel faces, resulting in a variation in the birefringence of the nonlinear crystal, the value of the applied external mechanical force being determined so as to obtain phase matching at a second phase-matching wavelength different from the first phase-matching wavelength; and 3) means for adjusting the external mechanical force for wavelength tunability in the frequency conversion cell.

Articles comprises iron oxide colloidal nanocrystals arranged within chains, wherein the chains of nanocrystals are embedded within a material used to form the article or a transfer medium used to transfer a color to the article are described. The material or transfer medium includes elastic properties that allow the nanocrystals to display a temporary color determined by the strength of an external force applied to the article, and the material or transfer medium includes memory properties that cause the displayed temporary color to dissipate when the external force is removed, wherein the dissipation of the displayed temporary color is sufficiently slow as to be visually observable by an average observer's unaided eye.

Articles comprises iron oxide colloidal nanocrystals arranged within chains, wherein the chains of nanocrystals are embedded within a material used to form the article or a transfer medium used to transfer a color to the article are described. The material or transfer medium includes elastic properties that allow the nanocrystals to display a temporary color determined by the strength of an external force applied to the article, and the material or transfer medium includes memory properties that cause the displayed temporary color to dissipate when the external force is removed, wherein the dissipation of the displayed temporary color is sufficiently slow as to be visually observable by an average observer's unaided eye.

According to one aspect, the invention relates to a frequency conversion cell (10) comprising: a birefringent nonlinear crystal (12) characterized by a first phase-matching wavelength, having an input face (121.sub.A) for receiving at least one incident beam, an output face (121.sub.B) for emitting at least one frequency-converted beam, and at least two parallel faces (120.sub.A, 120.sub.B) different from the input and output faces; means (14, 14.sub.A) for applying an external mechanical force to at least one of said parallel faces (120.sub.A), called a force application face, resulting in a variation in the birefringence of the nonlinear crystal, the value of the applied external mechanical force being determined so as to obtain phase matching in the nonlinear crystal at a second phase-matching wavelength different from the first phase-matching wavelength.

A display device includes: a plurality of pixel units, where each pixel unit includes two suppression color changing sub-pixel units configured for exciting light waves of different colors. Each suppression color changing sub-pixel unit includes: a first transparent electrostatic sheet and a second transparent electrostatic sheet which are disposed opposite to each other and insulated from each other, where the first transparent electrostatic sheet is disposed on a substrate and the second transparent electrostatic sheet is disposed on the first transparent electrostatic sheet. The display device further includes: a suppression color changing light emitting layer disposed between the first transparent electrostatic sheet and the second transparent electrostatic sheet; and a transparent pressure deformation sensor disposed at a side of the second transparent electrostatic that is away from the substrate.

Disclosed herein are a liquid crystal display device and an electronic pen system using the same. The liquid crystal display device includes an infrared reflection layer configured to reflect infrared irradiated thereto, the infrared reflection layer including an information pattern having virtual grid lines and a plurality of marks; and a liquid crystal layer formed on the infrared reflection layer and configured to be changed an orientation of liquid crystal molecules by an external pressure.

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.

A light detection and ranging (LiDAR) sensor includes detector(s), attenuator(s), and processor(s). The detector(s) receive backscattered light backscattered from at least one measurement location; and determine a current intensity of the backscattered light. The attenuator(s) is positioned between the at least one measurement location and the at least one detector. The processor(s) is configured to: select at least one of (1) a particular attenuator or (2) an attenuation level to use based on the current intensity of the backscattered light. The particular attenuator is configured to: selectively attenuate the backscattered light based on at least one of: (1) characteristics of the particular attenuator or (2) the attenuation level to use as selected by the at least one processor for the current intensity of the backscattered light.

A color changing or beam steering photonic device, which combines a high contrast metastructure (HCM) having a plurality of high index grating structures, into a low index membrane. In response to physical (or electrical) deformation of the membrane the low index gaps between adjacent grating bars changes which results in changing reflectance and transmission angles for steering a single wavelength of light and for causing a color change in said photonic device when subject to multiple light wavelengths. Deformation can result from direct physical stimulus, conversion from electrical or thermal to physical, and so forth. Refractive index change can also be initiated by carrier injection through electrodes. The apparatus is exemplified for use in color displays, beam steering, labeling micro entities, mechanical deformation sensing, camouflage, anti-counterfeiting, and other fields.

A spin-orbit torque (SOT) measuring apparatus includes a photoelastic modulator (PEM) configured to periodically modulate a polarization direction of linearly polarized incident light and emit a periodically modulated light, a first polarization rotator configured to rotate a polarization direction of the periodically modulated light, a voltage generator configured to generate an AC current to a sample to which light with the rotated polarization direction is to be emitted, a prism configured to split light reflected into first light and second light having different polarization directions, a balanced detector configured to output a signal corresponding to an intensity difference between the first light and the second light, a changing circuit configured to change a frequency component to the intensity difference, and an amplitude measurer configured to measure an amplitude of a frequency component corresponding to a modulation frequency of the PEM with the changed frequency component.