Abstract: A particle is provided that includes a first material and a second material, arranged to provide a Fano resonance effect, for example in the visible portion of electromagnetic spectrum. The first and second materials may be substantially clear in the visible portion of the electromagnetic spectrum. The first material may include an inorganic material, such as SiO2, TiO2, HfO2, ZrO2, diamond, or a combination thereof. The second material may include a polymer. The first material has a first refractive index and the second material has a second refractive index, where the first refractive index and second refractive index have a difference of 0.5 or greater, and 1.0 or less. The first material may form a core and the second material may form a shell surrounding the core. Alternatively, the first and second materials may form a Janus particle, an asymmetric dimer, or an aggregate.

Abstract: Techniques for determining characteristics of a stream of jetted material in a three-dimensional (3D) printer are disclosed. An example system includes an ejector configured to release molten droplets along a jetting path from the ejector to a build platform. The system also includes a sensor positioned adjacent to the jetting path and configured to generate an electrical signal in response to light emanating from the molten droplets. The system also includes an optical mask positioned adjacent to the jetting path, the optical mask comprising a plurality of regions configured to modulate the electrical signal generated by the sensor as the molten droplets travel along the jetting path. The system also includes one or more processing devices to receive the electrical signal, analyze the electrical signal to identify one or more characteristics of the molten droplets, and control the 3D printer based on the one or more characteristics.

Abstract: Techniques for determining characteristics of a stream of jetted material in a three-dimensional (3D) printer are disclosed. An example 3D printer includes an ejector configured to release molten droplets along a jetting path from the ejector to a build platform. The 3D printer also includes a sensor positioned adjacent to the jetting path and an optical mask positioned adjacent to the jetting path. The optical mask includes a plurality of regions comprising light-blocking regions and light-passing regions. The optical mask is configured to modulate a signal generated by the sensor as the molten droplets travel along the jetting path. The 3D printer also includes a controller to control the 3D printer based on the signal.

Abstract: Techniques for determining characteristics of a stream of jetted material in a three-dimensional (3D) printer are disclosed. An example system includes an ejector configured to release molten droplets along a jetting path from the ejector to a build platform. The system also includes an optical sensor positioned adjacent to the jetting path and configured to generate an electrical signal in response to light emanating from the molten droplets. The system also includes an optical mask positioned adjacent to the jetting path. The optical mask includes light-blocking regions and light-passing regions to modulate the electrical signal generated by the optical sensor. The system also includes one or more processing devices to receive the electrical signal from the optical sensor, process the electrical signal to identify characteristics of the molten droplets, and control the 3D printer based on the characteristics. The characteristics include an estimated temperature of the molten droplets.

Abstract: A resonant structure includes a conductive surface layer on a dielectric layer that produces an enhanced or reduced backscattered radiation in one or more resonant frequency bands when illuminated with electromagnetic energy. A transmitter illuminates the resonant structure with the electromagnetic energy at a first angle relative to the normal of the conductive surface. A receiver is operable to detect the enhanced or reduced backscattered radiation at the resonant frequency bands at a second angle relative to the normal of the conductive surface. The second angle is different from the first angle by at least five degrees. A processor coupled to the receiver and is operable to detect data encoded in one or both of a frequency response and a polarization response of the resonant structure based on the detected enhanced or reduced backscattered radiation.

Abstract: A particle is provided that includes a first material and a second material, arranged to provide a Fano resonance effect, for example in the visible portion of electromagnetic spectrum. The first and second materials may be substantially clear in the visible portion of the electromagnetic spectrum. The first material may include an inorganic material, such as SiO2, TiO2, HfO2, ZrO2, diamond, or a combination thereof. The second material may include a polymer. The first material has a first refractive index and the second material has a second refractive index, where the first refractive index and second refractive index have a difference of 0.5 or greater, and 1.0 or less. The first material may form a core and the second material may form a shell surrounding the core. Alternatively, the first and second materials may form a Janus particle, an asymmetric dimer, or an aggregate.

Abstract: A resonant structure includes a conductive surface layer on a dielectric layer that produces an enhanced or reduced backscattered radiation in one or more resonant frequency bands when illuminated with electromagnetic energy. A transmitter illuminates the resonant structure with the electromagnetic energy at a first angle relative to the normal of the conductive surface. A receiver is operable to detect the enhanced or reduced backscattered radiation at the resonant frequency bands at a second angle relative to the normal of the conductive surface. The second angle is different from the first angle by at least five degrees. A processor coupled to the receiver and is operable to detect data encoded in one or both of a frequency response and a polarization response of the resonant structure based on the detected enhanced or reduced backscattered radiation.