Dec. 10, 2009 - Manijeh Razeghi

Modern Atomic Engineering: Building Better Optoelectronics from the Atoms Up

Joint Meeting with Boston Chapter, LEOS

The 20th century has seen a variety of major discoveries in science and technology, especially in the area of compound semiconductors, quantum devices, and nanotechnology.  Nanoscale optoelectronics is a key area within nanotechnology, where modern design and fabrication tools allow us to realize compact devices with better efficiency and functionality than ever before.  Our optoelectronic systems, like Natural systems, are inherently nanoscale at their heart, yet whereas nature has to use ions and Classical physics , we can use electrons and Quantum physics. Electrons in semiconductors can be 5 orders of magnitude lighter and 8 orders of magnitude faster than ions, and, because of this, we can when we need to, detect electrons and photons on time scales of 1 nanosecond and less.

This talk will focus on recent advances in the atomic engineering of III-V semiconductor optoelectronic materials for a variety of applications important to everyday activities.  These applications span many areas, including industrial quality control, public health and safety, and telecommunications.  While our eyes only access a narrow part of the electromagnetic spectrum, some important applications require us to emit and/or detect at frequencies of light outside the visible.  In some cases we need to see a single photon clearly, and in other cases we need high power lasers that emit over 1021 photons per second.

In my talk, I will discuss problems and solutions relative to demonstrating devices spanning from ultraviolet (UV) to THz frequencies.  UV devices (emitters and detectors) will be discussed first, followed by infrared lasers and cameras.  In all cases, early attempts to develop these devices were limited by fundamental physical limitations such as material purity and size.  Many of these limitations were overcome by moving towards lower dimensional “quantum well” and even smaller “quantum dot” architectures.  It will be shown how intricate and subtle modern atomic engineering can be, and how, with quantum engineering, we can improve device performance tremendously.

After having covered modern optoelectronics, I will also talk about some of the technological tools and tricks that go into making the best possible devices and obtaining world record performances.  This includes paying meticulous attention to material growth, material characterization, device fabrication, and system demonstration.

Finally, I will show how, over the course of 15+ years, starting from scratch, I founded the Center for Quantum Devices which has grown to become a world class research facility at Northwestern University.

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Read more: Dec. 10, 2009 - Manijeh Razeghi

Nov. 19, 2009 - Irving J. Bigio

Elastic Light Scattering Spectroscopy For The Detection Of Pre-Cancer

Optical spectroscopy mediated by fiber-optic probes can be used to perform noninvasive, or minimally-invasive, real-time assessment of tissue pathology in-situ.  The method of elastic-scattering spectroscopy (ESS) is sensitive to the sub-cellular architectural changes, such as nuclear grade and nuclear to cytoplasm ratio, mitochondrial size and density, etc., which correlate with features used by pathologists when performing histological assessment.  The ESS method senses those morphology changes without actually imaging the microscopic structure.  Clinical demonstrations of ESS have been conducted in a variety of organ sites, with promising, and larger-scale clinical studies are now ongoing.  We have recently developed an analytical model that extracts, from the ESS spectra, the underlying physical correlates of the tissue relating to disease.

Read more: Nov. 19, 2009 - Irving J. Bigio

Oct. 14, 2009 - Joseph M. Schmitt

Imaging inside the Coronary Arteries with Optical Coherence Tomography (OCT)

Note: A Wednesday Meeting to be held at Boston University

Since it was first introduced over a decade ago, optical coherence tomography (OCT) has become a focus of bio-photonics research around the world.  A number of exciting advances, built on photonics technologies developed originally for the optical telecom industry, have fueled the development of the new OCT applications.  With the mission of bringing OCT from the research lab to the patient’s bedside, LightLab Imaging has pioneered the development and commercialization of OCT for guiding coronary interventions, particularly the implantation of stents. This presentation will review the basic principles of high-speed Fourier-domain OCT and review results of patient studies that illustrate the clinical utility of this new technology.

Read more: Oct. 14, 2009 - Joseph M. Schmitt

Sept. 17, 2009 - Barret Lippey

Introduction to Patents

Topics will include the rights that patents convey, basic concepts such as obviousness and inventorship, provisional patents vs. non-provisional patents, the foreign patent process, prior art search, the process of patent prosecution, parts of the patent application with an explanation of the requirements for each part, current trends in the US Patent Office, and patent issues related to optics.  The emphasis will be on practical knowledge that can help engineers and managers obtain the maximum possible benefit from the patent system.

Read more: Sept. 17, 2009 - Barret Lippey

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