Abstract: A whispering gallery mode dielectric resonator includes a conductive enclosure comprising a top, a bottom and walls. The resonator also includes a dielectric element disposed in the enclosure and operative to support a desired resonant mode that is dependent on a shape and dimensions of the dielectric resonator; and a mode selective coupling structure disposed over the enclosure and configured to selectively couple electromagnetic energy of the desired mode and configured not to substantially couple electromagnetic energy of a spurious mode supported in a region between the enclosure and the dielectric element.

Abstract: Improved microwave imaging using a reflector. By providing a reflective surface in the range of the imaging system, additional information is available for imaging objects. The relative surface provides silhouette information on the object, and increases the effective thickness of the object to aid analysis.

Abstract: A microwave imaging system for constructing a stereoscopic microwave image of an object includes an antenna array with a plurality of programmable antenna elements and a processor. Each of the antenna elements is capable of being programmed with a respective first direction coefficient to capture a first microwave image of the object from a first focal point on the array. In addition, each of the antenna elements is capable of being programmed with a respective second direction coefficient to capture a second microwave image of the object from a second focal point on the array. The processor constructs the stereoscopic microwave image from the first and second microwave images.

Abstract: A nanoscale displacement detector includes a cantilever integrated with an optical resonator, referred to herein as a “microresonator.” The microresonator and cantilever are configured such that displacement of the cantilever relative to the microresonator causes a change in the resonant frequency of the microresonator. The change in the resonant frequency of the microresonator is used to monitor cantilever displacement. In an embodiment, the microresonator includes a cavity that faces the cantilever and the cantilever includes a protrusion that faces the microresonator and is aligned with the cavity.

Abstract: An antenna array for use within a microwave imaging system includes a plurality of reflecting antenna elements, each capable of being programmed with respective phase-shifts in a first pattern to direct a first beam of microwave radiation towards a first target, and each being capable of being programmed with respective phase-shifts in a second pattern to direct a second beam of microwave radiation towards a second target. To capture a microwave image of an object, the antenna elements are programmed with respective phase-shifts in an interleaved pattern including a portion of the first pattern and a portion of the second pattern.

Abstract: A microwave imaging system captures a microwave image of a target and minimizes noise in the microwave image using phase differentiation. A reflector antenna array is provided including a plurality of antenna elements for reflecting microwave radiation towards the target and for reflecting microwave radiation reflected from the target towards a microwave receiver. A processor programs the antenna elements with respective first phase shifts to capture a first microwave image of the target, and programs the antenna elements with respective second phase shifts to capture a second microwave image of the target. The first phase shift of each antenna element is 180 degrees different than the second phase shift for that antenna element. The processor minimizes noise from a combination of the first microwave image and the second microwave image.

Abstract: A microwave imaging system uses microwave radiation provided by a microwave source to image targets. The system includes an array of antenna elements that are capable of being programmed with a respective transmission coefficient to direct the microwave illumination from the microwave source toward a position on the target. The antenna elements are further capable of being programmed with a respective additional transmission coefficient to receive reflected microwave illumination reflected from the position on the target and direct the reflected microwave illumination towards a microwave receiver. A processor is operable to measure an intensity of the reflected microwave illumination to determine a value of a pixel within an image of the target. Multiple beams can be directed towards the target to obtain corresponding pixel values for use by the processor in constructing the image.

Abstract: A scanning panel for use in a microwave imaging system captures a microwave image of a target using two complementary arrays of antenna elements. Each of the antenna elements in a first array is capable of being programmed with a respective phase delay to direct a transmit beam of microwave illumination toward the target in a transmit beam pattern, and each of the antenna elements in a second array is capable of receiving reflected microwave illumination reflected from the target in a receive beam in a receive beam pattern complementary to the transmit beam pattern. The microwave image of the target is formed at an intersection between the transmit beam and the receive beam.

Abstract: A microwave imaging system suppresses sidelobes in a microwave image captured using a sparse antenna array using an illumination system that operates in two different illumination modes. The antenna array including subarrays of antenna elements arranged in a sparse geometry to form complementary subarray patterns. The illumination system operates in a first mode to transmit microwave illumination to both of the complementary subarray patterns of the antenna array and receive reflected microwave illumination from both of the complementary subarray patterns of the antenna array to produce a first receive signal. The illumination system further operates in a second mode to transmit microwave illumination to a first one of the complementary subarray patterns of the antenna array and receive reflected microwave illumination from a second one of the complementary subarray patterns of the antenna array to produce a second receive signal.

Abstract: A method of bonding a transparent optical element to a light emitting device having a stack of layers including semiconductor layers comprising an active region is provided. The method includes elevating a temperature of the optical element and the stack and applying a pressure to press the optical element and the stack together. In one embodiment, the method also includes disposing a layer of a transparent bonding material between the stack and the optical element. The bonding method can be applied to a premade optical element or to a block of optical element material which is later formed or shaped into an optical element such as a lens or an optical concentrator.

Abstract: A reflectarray utilizes switching devices with non-ideal impedance characteristics to vary the impedance of reflecting elements. The antennas of the reflecting elements are configured as a function of the impedance of the non-ideal switching devices to provide optimal phase-amplitude performance. In particular, the antennas are configured such that the impedance of each antenna is proportional to the square root of the impedance of the non-ideal switching devices when in an on state and when in an off state.

Abstract: An inspection system uses microwave radiation to capture a microwave image of a transportable item. The system includes a transmit scanning panel including a transmit array of transmit antenna elements, each being programmable with a respective phase delay to direct a transmit beam of microwave radiation toward a target of the transportable item for transmission of the microwave radiation through the target. The system further includes a receive scanning panel including a receive array of receive antenna elements, each being programmable with a respective phase delay to receive a receive beam of microwave radiation from the target. A processor measures the amplitude and phase of the microwave radiation in the receive beam to determine a relative value of a pixel within the microwave image of the transportable item based on a reference value of the pixel.

Abstract: A technique for imaging an object with a coherent beam of electromagnetic radiation involves sequencing at least a portion of the coherent beam through a set of orthogonal transverse spatial modes and summing the output signals that result from set of orthogonal transverse spatial modes. To create an image of an object, the coherent beam is applied to multiple spots on the object and sequenced through the same set of orthogonal transverse spatial modes at each spot. The output signals generated from the sequencing are summed on a per-spot basis.

Abstract: Light emitting devices with improved light extraction efficiency are provided. The light emitting devices have a stack of layers including semiconductor layers comprising an active region. The stack is bonded to a transparent optical element having a refractive index for light emitted by the active region preferably greater than about 1.5, more preferably greater than about 1.8. A method of bonding a transparent optical element (e.g., a lens or an optical concentrator) to a light emitting device comprising an active region includes elevating a temperature of the optical element and the stack and applying a pressure to press the optical element and the light emitting device together. A block of optical element material may be bonded to the light emitting device and then shaped into an optical element. Bonding a high refractive index optical element to a light emitting device improves the light extraction efficiency of the light emitting device by reducing loss due to total internal reflection.

Abstract: Light emitting devices with improved light extraction efficiency are provided. The light emitting devices have a stack of layers including semiconductor layers comprising an active region. The stack is bonded to a transparent lens having a refractive index for light emitted by the active region preferably greater than about 1.5, more preferably greater than about 1.8. A method of bonding a transparent lens to a light emitting device having a stack of layers including semiconductor layers comprising an active region includes elevating a temperature of the lens and the stack and applying a pressure to press the lens and the stack together. Bonding a high refractive index lens to a light emitting device improves the light extraction efficiency of the light emitting device by reducing loss due to total internal reflection. Advantageously, this improvement can be achieved without the use of an encapsulant.

Abstract: An imaging system includes an optical (visible-light or near IR) imaging system and a microwave imaging system. The optical imaging system captures an optical image of the object, produces optical image data representing the optical image and extracts optical image information from the optical image data. The microwave imaging system produces microwave image data representing a microwave image of the object in response to the optical image information.

Abstract: An optical port with directional control. The port includes a transmitter, receiver, and first actuator. The transmitter generates an outgoing light signal that propagates in a transmission direction in response to an outgoing electrical signal. The receiver receives an incoming light signal and generating an incoming electrical signal therefrom, the receiver having a reception direction aligned with the transmission direction. The first actuator alters the transmission direction of the outgoing light signal in response to a first control signal. In one embodiment, the first actuator determines the direction of the outgoing light signal in a first plane, and a second actuator controls the direction of the outgoing light signal by an amount determined by a second control signal. The second actuator controls the direction of the outgoing light signal in a second plane that is orthogonal to the first plane.

Abstract: A light emitting device and a method of increasing the light output of the device utilize a chirped multi-well active region to increase the probability of radiative recombination of electrons and holes within the light emitting active layers of the active region by altering the electron and hole distribution profiles within the light emitting active layers of the active region (i.e., across the active region). The chirped multi-well active region produces a higher and more uniform distribution of electrons and holes throughout the active region of the device by substantially offsetting carrier diffusion effects caused by differences in electron and hole mobility by using complementary differences in layer thickness and/or layer composition within the active region.

Abstract: Light emitting devices with improved light extraction efficiency are provided. The light emitting devices have a stack of layers including semiconductor layers comprising an active region. The stack is bonded to a transparent optical element having a refractive index for light emitted by the active region preferably greater than about 1.5, more preferably greater than about 1.8. A method of bonding a transparent optical element (e.g., a lens or an optical concentrator) to a light emitting device comprising an active region includes elevating a temperature of the optical element and the stack and applying a pressure to press the optical element and the light emitting device together. A block of optical element material may be bonded to the light emitting device and then shaped into an optical element. Bonding a high refractive index optical element to a light emitting device improves the light extraction efficiency of the light emitting device by reducing loss due to total internal reflection.

Abstract: The hologram card generates a hologram image in response to an illumination light beam. The hologram card comprises a substrate of a first plastic material having a first refractive index. The substrate has a contoured surface. The contoured surface is formed to include localized topological features constituting a diffractive optical element. The diffractive optical element is structured to generate a hologram image when illuminated by the illumination light beam. The hologram card also comprises a protective layer of a second plastic material having a second refractive index that differs from the first refractive index by less than 0.2. The protective layer covers the contoured surface of the substrate. The protective layer is chemically bonded to, and directly contacts, at least the topological features constituting the diffractive optical element.