University of Michigan

Theodore B Norris

James R Baker, Jr

Jing Yong Ye

Yunbo Guo

Zhaohui Zhong

Lajos P Balogh

Thomas Thommey

Mon Myaing

Matthew N O'Donnell

Lingjie Jay Guo

Nicholas Alexander Kotov

Jeffrey Allen Fessler

Jason E Gestwicki

Wonjin Choi

Nils Walter

Tommaso F Bersano-Begey

Chang-Hua Liu

Susanne M Milas

Stanislav Y Emelianov

You-Chia Chang

Kyle W Hollman

Gong Cheng

James R Baker

Jingyong Ye

Zhengyu Huang

Cheng Frank Zhong

Image security is becoming an increasingly important issue with the progress of deep learning based image manipulations, such as deep image inpainting and deep fakes. There has been considerable work to date on detecting such image manipulations using better and better algorithms, with little attention being paid to the possible role hardware advances may have for more powerful algorithms. This disclosure proposes to use a focal stack camera as a novel secure imaging device for localizing inpainted regions in manipulated images. Applying convolutional neural network (CNN) methods to focal stack images achieves significantly better detection accuracy compared to single image based detection.

Focal stack camera as secure imaging device and image manipulation detection method

Kirigami-based optic devices are provided that include a tunable kirigami-based component comprising a plurality of bridge structures and a plurality of openings therebetween to form a grating structure. At least one surface of the kirigami-based component is micropatterned with a plasmonic material so that the grating is configured to induce or modulate rotational polarity of a beam of electromagnetic radiation as it passes through the plurality of openings. In certain aspects, the micropattern may be a gold herringbone pattern. The kirigami-based component has tunable 3D topography, which when stretched, exhibits polarization rotation angles as high as 80&#xb0; and ellipticity angles as high as 34&#xb0; due to the topological equivalency of helix. The kirigami-based components are compact electromagnetic modulators and can be used in THz circular dichroism (TCD) spectroscopy, for example, in a stacked configuration as a modulator, as an encryptor/decryptor for secure communication, in biomedical imaging, and LIDAR systems.

Kirigami chiroptical modulators for circular dichroism measurements in terahertz and other parts of electromagnetic spectrum

A photodetector is provided with a thin film double layer heterostructure. The photodetector is comprised of: a substrate; a channel layer of a transistor deposited onto a top surface of the substrate; a source layer of the transistor deposited on the top surface of the substrate; a drain layer of the transistor deposited on the top surface of the substrate, the source layer and the drain layer disposed on opposing sides of the channel layer; a barrier layer deposited onto the channel layer; and a light absorbing layer deposited on the barrier layer. The light absorbing layer is configured to absorb light and, in response to light incident on the light absorbing layer, electrical conductance of the channel layer is changed through hot carrier tunneling from the light absorbing layer to the channel layer.

Photodetectors based on double layer heterostructures

A photonic crystal-metallic (PCM) structure receives an input light signal from a light source. The PCM structure includes a metal structure and a photonic crystal structure disposed adjacent the metal structure. The photonic crystal structure is configured to receive the input light signal such that the input light signal excites surface plasmons of the metallic structure and such that the input light signal is internally reflected within the photonic crystal structure.

Photonic crystal-metallic structures and applications

A system for determining whether interaction occurs between a trial substance and a target substance. The system includes a photonic crystal sensor having a photonic crystal structure and a defect member disposed adjacent the photonic crystal structure. The defect member defines an operative surface able to receive the target substance and the trial substance. The system further includes a light source that inputs a light signal to the photonic crystal structure and the defect member. The light signal is internally reflected, and a resultant output signal is outputted. The output signal relates to whether the trial substance interacts with the target substance at the operative surface. Furthermore, the system includes an identity detector that identifies the trial substance that interacts with the target substance.

Analytical system with photonic crystal sensor

A method and apparatus of multi-dye analysis of particles using flow cytometer. The method includes dying particles to be detected using two or more dyes; urging the particles through a capillary in a non-uniform flow; exciting a first of the particles within the capillary using a multiphoton excitation laser beam causing the two or more dyes each to fluoresce thereby producing a first output signal and a second output signal respectively; and detecting the first output signal and the second output signal. A second of the particles within the capillary being excited using the multiphoton excitation laser beam causing the two or more dyes each to fluoresce thereby producing a third output signal and a forth output signal respectively. The method finally includes comparing a ratio of the first output signal and the second output signal to a ratio of the third output signal and the forth output signal to detect a desired change in the particles.

Quantitative two-photon flow cytometry

A photonic crystal sensor for outputting an output signal using a light source. The photonic crystal sensor includes a photonic crystal structure and a defect member disposed adjacent the photonic crystal structure. The defect member defines an operative surface. An input light signal from the light source is inputted to the photonic crystal structure and defect member and is internally reflected to thereby output the output signal. Also, the output signal relates to a condition at the operative surface.

Photonic crystal sensor

An additive, preferably in the form of metal nanoparticles or nanodomains, greatly improves a laser-based method and system for inducing optical breakdown. The use of ultrashort laser pulses to induce laser-induced breakdown (LIB) in metal nanoparticles or nanocomposites makes it possible to reduce significantly the threshold laser energy required for LIB. Such nanoscale (submicron) metallic particles allows one to control the LIB process. The nanoparticles can be synthesized so as to target specific biological structures or tissues (dendrimer nanoparticles are one system for which this has been demonstrated). This opens up the possibility of performing LIB for targeted cancer treatment or microsurgery.

Laser-based method and system for enhancing optical breakdown

An acoustic monitoring method and system in laser-induced optical breakdown (LIOB) provides information which characterize material which is broken down, microbubbles in the material, and/or the microenvironment of the microbubbles. In one embodiment of the invention, femtosecond laser pulses are focused just inside the surface of a volume of aqueous solution which may include dendrimer nanocomposite (DNC) particles. A tightly focused, high frequency, single-element ultrasonic transducer is positioned such that its focus coincides axially and laterally with this laser focus. When optical breakdown occurs, a microbubble forms and a shock or pressure wave is emitted (i.e., acoustic emission). In addition to this acoustic signal, the microbubble may be actively probed with pulse-echo measurements from the same transducer. After the microbubble forms, received pulse-echo signals have an extra pulse, describing the microbubble location and providing a measure of axial microbubble size. Wavefield plots of successive recordings illustrate the generation, growth, and collapse of microbubbles due to optical breakdown. These same plots can also be used to quantify LIOB thresholds.

Acoustic monitoring method and system in laser-induced optical breakdown (LIOB)

A scanning microscope having a laser outputting an excitation laser beam and a fiber member having a first core and a second core. The second core is generally disposed within the first core and is operable to receive the excitation laser beam from the laser and transmit the excitation laser beam to a sample to be tested. A moveable stage supports an end of the fiber member and/or a sample to be tested and is operable to move the end of the fiber member and the sample to be tested relative to each other.

Double-clad fiber scanning microscope

A fluorescence detection system for testing a sample having at least one fluorophore. The fluorescence detection system comprises a white light generation system outputting a white light pulse. The white light pulse has a first frequency range and a first time duration. The white light pulse excites the at least one fluorophore of the sample to emit a fluorescence. The fluorescence has a second frequency range and a second time duration, wherein the first time duration is less than the second time duration. A time-resolving detector receives the fluorescence and at least a portion of the white light pulse and separates the fluorescence from the portion of the white light pulse.

Whole spectrum fluorescence detection with ultrafast white light excitation

An optical fiber for use in fiber optic sensing of a test sample includes a first core and a second core. The second core is generally coaxially disposed within the first core and is sized smaller than the first core. The second core is capable of delivering pulsed laser energy from the laser for nonlinear optical excitation of the test sample. Nonlinear optical feedback signals can then be collected in both the first core and second core for improved detection efficiency relative to conventional single-mode and multi-mode fibers.

Growing community of inventors

Dexter, MI, United States of America

Theodore B Norris