Electrical and Electronic Engineering - Research Publications
Permanent URI for this collection
Search Results
1 - 7 of 7
-
ItemAll-silicon, optics-free microspectromer chip based on vertical waveguide array pixels(OSA & IEEE, 2021-01-01)We experimentally demonstrate a nanostructured silicon microspectrometer chip that consists of 144 pixels, each comprising an array of vertical waveguides of subwavelength period. We show that both broad- and narrow-band visible spectra can be reconstructed.
-
ItemMaterial identification by plasmonic infrared microspectrometer employing machine learning(Optica Publishing Group, 2021-01-01)We demonstrate a microspectrometer comprising plasmonic filters integrated with an infrared camera. Blackbody light illuminates the material being studied, with transmitted light collected by the microspectrometer. The latter uses machine learning to identify the material.
-
ItemTriple-helix tractor beam generation with a dielectric metasurface pancharatnam-berry phase hologram(Optica Publishing Group, 2021-01-01)We present a silicon-based Pancharatnam-Berry (PB) phase metasurface hologram that produces a triple-helix solenoid tractor beam from a Gaussian input beam. Our metasurface has a >90% diffraction efficiency and >75% transmission.
-
ItemPlasmonic Mid-Infrared Filter Array-Detector Array Chemical Classifier Based on Machine Learning(AMER CHEMICAL SOC, 2021-02-17)Numerous applications exist for chemical detection, ranging from the industrial production of chemicals to pharmaceutical manufacturing, environmental monitoring, and hazardous risk control. For many applications, infrared absorption spectroscopy is the favored technique, due to attributes that include short response time, high specificity, minimal drift, in situ operation, negligible sample disruption, and reliability. The workhorse instrument for infrared absorption is the Fourier transform infrared (FTIR) spectrometer. While such systems are suitable for many purposes, new applications would be enabled by small, lightweight, low power and low cost infrared microspectrometers. Here we perform a detailed study on a microspectrometer chemical classifier comprising an array of plasmonic mid-infrared spectral filters used with a photodetector array, whose outputs are analyzed by a machine learning algorithm. We conduct simulations (including noise), demonstrating the identification of six gas-phase and six liquid-phase chemicals. We study the performance of our method at detecting the concentration of acetylene.
-
ItemVCSELs with On-Facet Metasurfaces for Polarization State Generation and Detection(WILEY-V C H VERLAG GMBH, 2021-05)Abstract Polarization plays a critical role in optical systems that range from optical communications to imaging, lithography, metrology, and data storage. Thus, in systems that need to generate a certain polarization state, a light source (e.g., laser) is combined with polarization control elements such as polarizers, polarizing beam splitters, and waveplates. Similarly, in systems requiring polarization state detection, such elements are combined with photodetectors. There is currently a trend toward miniaturized optical systems. This motivates the question of how to achieve what may be argued as an ultimate level of miniaturization: a single chip that can both generate light with a prescribed polarization state and detect the polarization state of light impinging upon it. This paper demonstrates this via vertical cavity surface emitting lasers (VCSELs) with on‐facet metasurfaces. Two classes of devices are demonstrated. The first class uses high‐index dielectric metasurfaces (amorphous silicon nanofins), whereas the second class uses plasmonic metasurfaces (aluminum bilayer gratings). Each can operate as a laser (to generate) and as a photodetector (to detect) circularly or linearly polarized light.
-
ItemVectorial Holograms with Spatially Continuous Polarization Distributions(AMER CHEMICAL SOC, 2021-02-24)Metasurface-based holography presents opportunities for applications that include optical displays, data storage, and optical encryption. Holograms that control polarization are sometimes referred to as vectorial holograms. Most studies on this topic have concerned devices that display different images when illuminated with different polarization states. Fewer studies have demonstrated holographic images whose polarization varies spatially, i.e., as a function of the position within the image. Here, we experimentally demonstrate a vectorial hologram that produces an image with a spatially continuous distribution of polarization states, for the first time to our knowledge. An unlimited number of polarization states can be achieved within the image. Furthermore, the holographic image and its polarization map (polarization vs position in image) are independent. The same image can be thus encoded with different polarization maps. As far as we know, our approach is conceptually new. We anticipate that it could broaden the application scope of metasurface holography.
-
ItemLight field on a chip: metasurface-based multicolor holograms(SPIE-SOC PHOTO-OPTICAL INSTRUMENTATION ENGINEERS, 2021-03)