An apparatus includes a sensor module. The sensor module includes an electromagnetic radiation sensor configured to provide electromagnetic radiation sensor data. The sensor module further includes a coded mask configured to modulate electromagnetic radiation incident to the electromagnetic radiation sensor and from which the electromagnetic radiation sensor data is generated. The apparatus further includes a computation module configured to obtain the electromagnetic radiation sensor data from the electromagnetic radiation sensor. The computation module is further configured to detect a property from the electromagnetic radiation sensor data using an artificial neural network. The computation module is further configured to output information related to the detected property via an output.

An active IR camouflage device may include a base layer, a first dielectric layer over the base layer, a phase transition material layer over the first dielectric layer, a second dielectric layer over the phase transition material layer, and a first metal layer over the second dielectric layer and defining a pattern of openings therein. The active IR camouflage device may have circuitry configured to selectively cause a transition from a first phase state to a second phase state of the phase transition material layer to control IR reflectance/emission of a top plasmonic layer, making it appear/disappear from the IR detector/camera. In some embodiments, the active IR camouflage device may also include a second metal layer between the base layer and the first dielectric layer.

In various embodiments, the present disclosure provides devices and systems for detecting the blood pressure of a user. In one embodiment, an optoelectronic device includes an array of avalanche photodiodes operating in Geiger mode. A tunable optical filter is optically coupled to the array and receives a light beam reflected from a vascularized tissue of the user, in response to the vascularized tissue being illuminated by an optical source.

Provided is an optical body capable of arbitrarily and quickly controlling the optical characteristics of incident light. A refractive index variable layer (8) formed of PLZT or other material and a magneto-optical material layer (9) formed of garnet or other material are provided side by side between a first reflective layer (3) and a second reflective layer (5). If linearly polarized light is made incident from the side of the first reflective layer (3), the incident light interacts with the magneto-optical material layer (9) and is converted into a right-circularly polarized light component and a left-circularly polarized light component. A very small retardation occurring between both the right- and left-circularly polarized light components is amplified through multiple reflections between the pair of reflective layers (3, 5) and is controlled according to a controlled refractive index of the refractive index variable layer (8).

A reflective structure includes an input/output port and an optical splitter coupled to the input/output port. The optical splitter has a first branch and a second branch. The reflective structure also includes a first resonant cavity optically coupled to the first branch of the optical splitter. The first resonant cavity comprises a first set of reflectors and a first waveguide region disposed between the first set of reflectors. The reflective structure further includes a second resonant cavity optically coupled to the second branch of the optical splitter. The second resonant cavity comprises a second set of reflectors and a second waveguide region disposed between the second set of reflectors.

An optical device may include a laser emitter to generate a first laser beam and a second laser beam with orthogonal polarization states. The optical device may include first and second photodetectors to generate respective first currents based on optical powers of the first and second laser beams. The optical device may include a polarization-based beam splitter to combine the first and second laser beams. The optical device may include a wavelength filter to filter the first and second laser beams based on respective wavelengths of the first and second laser beams. The optical device may include a third photodetector and a fourth photodetector to generate respective second currents based on optical powers of the first and second laser beams after filtration. The wavelengths of the first and second laser beams may be controlled based on the first currents and the second currents.

An optical transmitter and a method of producing a low-photon-density modulated optical signal are disclosed. The optical transmitter and method include an optical source configured to emit a continuous optical carrier waveform, a dilation module configured to apply a spreading code to a data payload to spread each of the plurality of symbols in time to expand the symbol duration by a dilation factor and produce a corresponding plurality of time-dilated symbols, the plurality of time-dilated symbols having a lower photon density than the plurality of symbols; a mapping module configured to map the plurality of time-dilated symbols to a modulation scheme; and a modulator configured to modulate the optical carrier waveform with the plurality of time-dilated symbols according to the modulation scheme to produce the low-photon-density modulated optical signal encoded with the plurality of time-dilated symbols corresponding to the data payload.

Tunable filter arrays include an array of liquid crystal (LC) tunable Fabry-Perot (FP) microcavities. The microcavities are defined by first and second reflectors and an LC layer situated between the reflectors. The tunable filter is secured to an image sensor array so that the LC tunable microcavities are coupled to respective photodetectors of the image sensor array. Patterned electrodes are situated about the LC layer to tune the microcavities.

An optical receiver includes a photonic integrator configured to accumulate optical signal energy corresponding to the input optical signal during an integration period, and to produce an output optical signal at an end of the integration period, the output optical signal having a higher intensity than the input optical signal, a shutter operable between a closed position and an open position, the shutter configured to prevent the output optical signal from exiting the photonic integrator when in the closed position and to allow the output optical signal to exit the photonic integrator when in the open position, a synchronizer coupled to the shutter and configured to control the shutter between the open position and the closed position; and a photodetector configured to receive the output optical signal when the shutter is in the open position and to produce an electrical signal corresponding to the output optical signal.

The present invention provides a Fabry-Perot sensor for measuring inclination. Wherein the present inclinometer is fixed on a static detected object in application use, the mass block is flexibly connected to the top plate, thus the line between the center of gravity of the mass block and the connecting point on the top plate is perpendicular to the horizontal plane; a Fabry-Perot cavity is formed between the reflecting surface disposed at one end of the mass block and the end of the optic fiber. The detected object will be in a static state after tilting, the line between the center of gravity of the mass block and its connecting point on the top plate is still perpendicular to the level plane and the F-P cavity length will have a variation. Then the change of cavity length can be measured in accordance with the Fabry-Perot principle, thereby the tilting angle of the mass block is able to be further measured. Then the tilting angle is also the inclination of the detected object. The sensor provided in present invention has advantages such as simplicity, convenience and high precision and has wide application prospective.