Seeing with the Nano Eye: Accessing Structure, Coupling and Dynamics of Matter on its Natural Length and Time Scales

Dr. Markus Raschke presents a seminar on Seeing with the Nano Eye: Accessing Structure, Coupling and Dynamics of Matter on its Natural Length and Time Scales. To understand and ultimately control the properties of most functional materials, from molecular soft-matter to quantum materials, requires access to the structure, coupling, and dynamics on the elementary time and length scales that define the microscopic interactions in these materials. To gain the desired nanometer spatial resolution with simultaneous spectroscopic specificity we combine scanning probe microscopy with different optical, including coherent, nonlinear, and ultrafast spectroscopies. The underlying near-field interaction mediated by the atomic-force or scanning tunneling microscope tip provides the desired deep-sub wavelength nano-focusing enabling few-nm spatial resolution. I will introduce our generalization of the approach in terms of the near-field impedance matching to a quantum system based on special optical antenna-tip designs. The resulting enhanced and qualitatively new forms of light-matter interaction enable measurements of quantum dynamics in an interacting environment or to image the electromagnetic local density of states of thermal radiation. Other applications include the inter-molecular coupling and dynamics in soft-matter hetero-structures, surface plasmon/phonon interferometry as a probe of electronic structure and dynamics in 2D materials, and quantum phase transitions in correlated electron materials. These examples highlight the general applicability of the new near-field microscopy approach, complementing emergent X-ray and electron imaging tools, aiming towards the ultimate goal of probing matter on its most elementary spatio-temporal level.

Overcoming Diffraction Limitations in Optical Imaging

Optical computational imaging seeks enhanced performance and new functionality by the joint design of illumination, optics, detectors, and reconstruction algorithms. In this talk we discuss how this approach helps overcome the diffraction limit in fluorescence microscopy. Abbe’s resolution limit has been overcome after more than 130 years enabling unprecedented opportunities for optical imaging at the nanoscale. Fluorescence imaging using photoactivatable or photoswitchable molecules within computational optical systems offers single molecule sensitivity within a wide field of view from far field measurements. The advent of three-dimensional point spread function engineering associated with optimal reconstruction algorithms provides a unique approach to further increase resolution in three dimensions. Compressive imaging techniques further enable resolution of dense emitters and enable acceleration of the super-resolution data collection.

Talk Science Now

Sandra Tsing Loh provides a seminar on science communication. Among her many roles as an actress, author, and artist, Sandra Tsing Loh is the host of the daily NPR radio program, The Loh Down on Science, where she delivers the latest in science in a humorous, yet informative minute-long broadcast. In addition, she leads the Science Communication course at UC Irvine, where she teaches young scientists how to communicate their work to the general public and avoid pitfalls in conveying complicated and controversial science. During this seminar, Sandra will show how scientists can share their projects in fun and engaging ways without relying on difficult, technical terminology.

STROBE Tutorial: Fundamentals of Algorithms for Computational Imaging

Dr. Emrah Bostan presents a tutorial on the Fundamentals of Algorithms for Computational Imaging. In this talk, we consider practical algorithms for inverse problems in imaging. Adopting a suitable language, the concept is to “invert” the data acquisition process that relates an unknown image to observable measurements. By doing so, one obtains the spatial distribution of physical parameters. Since we retrieve information about entities—via solving inverse problems—that we are unable to observe directly, the topic is among the most intensively studied mathematical problems in the field. To have an expanded perspective, we shall be placed at the interplay of the deterministic and the stochastic approaches. Starting from linear image reconstruction algorithms, we shall review recent techniques that are nonlinear. We will present examples of such algorithms used in practical cases such as phase retrieval and lensless imaging.

STROBE Tutorial: 3D Electron Tomography

Dr. Peter Ercius provides a tutorial on 3D Electron Tomography. Transmission electron microscopy (TEM) provides sub-Angstrom image resolution such that the atomic structure of materials is readily visible. Such high-resolution TEM images are routinely used to analyze nano-structures in materials science. However, these are only projections of complex three-dimensional structures, and the lost information is critical to determine structure/function relationships. Electron tomography is a technique that recovers the lost information along the projection direction from a series of 2D images at different viewing angles and has become increasingly important for quantitative 3D characterization of a wide range of materials. This tutorial will cover the basic theory, image processing and reconstruction algorithms of electron tomography and recent advancements in atomic resolution tomography.

STROBE Tutorial: Optical Nano-probe Imaging

The diffraction of light conventionally limits the spatial resolution of an optical microscope. Research at STROBE reaches into the deep sub-wavelength regime using light scattering of nano-objects ranging from molecules to tiny metal tips. Covering the wavelength range from the visible into the far-infrared, these ultra-microscopes can probe from chemical composition to quantum states of all classes of materials. This tutorial gives an introduction into the basic imaging principles and develops perspective for its future development.

STROBE Tutorial: Coherent Diffractive Imaging

Dr. Daniel Adams provides a tutorial on Coherent Diffractive Imaging. Research pioneered by STROBE leaders takes a “lensless” microscopy approach. By shooting light at an object and using fundamental principles of wave physics, we can analyze the resulting scatter pattern to reconstruct an image of the object. This apprach is called coherent diffractive imaging, and this Tutorial describes its many unique and powerful benefits to imaging science.

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