CLEO Presents Cutting-Edge Research on Optics, Lasers

Smartphone-based cancer detection, a telecom-based time cloak and UV-LEDs that slow food rot are just a few of the cutting-edge applications of optics and lasers that will be discussed next week at CLEO: 2013, the Conference on Lasers and Electro-Optics.

More than 1800 technical presentations make CLEO the premier international forum for scientific and technical optics, say conference organizers The Optical Society (OSA), IEEE Photonics Society and the American Physical Society's (APS) Division of Laser Science. CLEO: 2013 builds on the long-established CLEO/QELS conference and its world-renowned peer-reviewed program.

CLEO: 2013 offers high-quality content in five core event elements featuring breakthrough research and applied innovations in ultrafast lasers, energy-efficient optics, quantum electronics, biophotonics and more.

Here's a sampling of sessions that technical conference attendees can attend:

Detecting Disease with a Smartphone Accessory

A new chemically based, plug-in optical sensor developed for smartphones at Cornell University could be used for in-the-field diagnosis of a cancer linked to AIDS.

As antiretroviral drugs that treat HIV have become more commonplace, the incidence of Kaposi’s sarcoma, a type of cancer linked to AIDS, has decreased in the US. The disease remains prevalent in sub-Saharan Africa, however, where poor access to medical care and lab tests only compounds the problem. Now, Cornell engineers have created a new smartphone-based system consisting of a plug-in optical accessory and disposable microfluidic chips.

“The accessory provides an ultraportable way to determine whether or not viral DNA is present in a sample,” said mechanical engineer David Erickson, who developed the technique along with his graduate student, biomedical engineer Matthew Mancuso.

The addition of target viral DNA causes the nanoparticles to form aggregate "clumps," which leads to a change in their color. Courtesy of Matthew Mancuso.

Unlike other methods that use smartphones for diagnostic testing, this new system is chemically based and does not use the phone's built-in camera. Instead, gold nanoparticles are combined with short DNA snippets that bind to Kaposi's DNA sequences, and a solution with the combined particles is added to a microfluidic chip. In the presence of viral DNA, the particles clump together, which affects the transmission of light through the solution. This causes a color change that can be measured with an optical sensor connected to a smartphone via a micro-USB port. When little or no Kaposi's virus DNA is present, the nanoparticle solution is a bright red; at higher concentrations, the solution turns a duller purple, providing a quick method to quantify the amount of Kaposi's DNA.

But detecting Kaposi’s sarcoma is not the only goal: “Nanoparticle assays similar to the one used in our work can target DNA from many different diseases,” such as methicillin-resistant Staphylococcus aureus (MRSA), a bacterium responsible for several difficult-to-treat infections in humans, and syphilis, Mancuso said.

The smartphone reader could also work with other color-changing reactions, such as the popular enzyme-linked immunosorbent assay (ELISA), a common tool in medicine to test for HIV, hepatitis, food allergens, and E. coli. The lab also has created smartphone accessories for use with the color-changing strips in pH and urine assays. “These accessories could form the basis of a simple, at-home, personal biofluid health monitor,” he said.

The technique could also be adapted for detecting a range of other conditions, from E. coli infections to hepatitis. Mancuso will describe the work in his presentation, “Smartphone Based Optical Detection of Kaposi’s Sarcoma Associated Herpesvirus DNA,” at 2 p.m. on Monday, June 10, at the Marriott San Jose.

Telecom-Based Time Cloak

An alternative “temporal cloaking” method that uses standard optical communications components will be presented by Joseph Lukens of Purdue University. Using off-the-shelf phase modulators and fibers commonly found in commercial optical communications, the Purdue team achieved a cloaking capability of 46 percent, potentially making the concept practical for commercial applications. (See: 'Temporal Cloaking' for Communications).

Previous research on temporal cloaking — which hides data being transmitted over time, as opposed to spatial cloaking, which hides physical objects — required complex, ultrafast-pulsing femtosecond lasers and could cloak only a small fraction — about 10,000th of a percent — of the time available for sending data in optical communications.

The 9-day Fresh Strawberry

A team from the US Department of Agriculture's (USDA) Food Components and Health Laboratory in Beltsville, Md., and Sensor Electronic Technology Inc. (SETi) in Columbia, S.C., has demonstrated that low-irradiance ultraviolet (UV) light directed at strawberries over long exposure periods at low temperature and very high humidity — typical home refrigerator conditions — delays spoilage.

UV-B (equal energy) treatment prevents damaged areas from spreading while also inhibiting mold growth. This is a critical aspect of the technology — the ability to "tune" the UV to the most effective part of the spectrum, something that would be difficult and much less efficient using a typical mercury UV source. Courtesy of Sensor Electronic Technology Inc. (SETi).

The team used a novel device incorporating UV-LEDs to experiment with two batches of strawberries purchased locally. They placed one batch in a dark refrigerator and one batch in a refrigerator exposed to UV-LEDs. Results showed that the UV-treated berries had their shelf life extended twofold — nine days mold-free — over darkened berries, as judged by weight, moisture content, concentration of select phytochemicals, visible damage and mold growth.

The results are significant because previous attempts using traditional UV light sources for storage of produce resulted in severe drying, and it was unknown whether the advantages of long exposure to low-level UV light would be effective against rot.

“These findings are expected to have a major impact on the appliance business to extend the shelf life and preserve nutritional value of fresh produce while reducing waste and saving money for every household,” said Remis Gaska, SETi president and CEO.

The presentation ATh3N.3., “Deep Ultraviolet (DUV) Light-Emitting Diodes (LEDs) to Maintain Freshness and Phytochemical Composition During Postharvest Storage,” by lead USDA researcher Stephen Britz will take place Thursday, June 13, at 2:45 p.m. in the San Jose Convention Center.

Ink-Jet-Printed Quantum Dot LEDs for Cheaper, 'Greener' Lighting

A promising line of research at the University of Louisville in Kentucky involves combining organic LEDs (OLEDs) with inorganic quantum dots — tiny semiconductor crystals that emit different colors of light depending on their size. These “hybrid” OLEDs, also called quantum dot LEDs (QD-LEDs), increase the efficiency of the light-emitting devices and also increase the range of colors that can be produced. But commercially manufacturing this promising green technology is still difficult and costly.

Novel cadmium selenide (CdSe) quantum dots with ligand enhancement chemistry. The vials on the left contain quantum dots; the vial on the right contains solvent without quantum dots. Courtesy of Delaina Amos.

According to Louisville professor and principal investigator Delaina Amos, materials costs and manufacturing processes have been major barriers to using OLEDs in everyday lighting devices.

“There’s a reason you don’t see OLED lights on sale at the hardware store,” she said. That's why her team is developing new materials and production methods using modified quantum dots and ink-jet printing.

To apply the quantum dots to their hybrid devices inexpensively, the Louisville researchers use ink-jet printing, a popular method in recent years for spraying quantum dots and OLED materials onto a surface with great precision.

Unlike other groups experimenting with this method, Amos' team has focused on adapting the technique for use in a commercial setting, in which mass production minimizes expense and translates to affordable off-the-shelf products.

"We are currently working at small scale, typically one inch by one inch for the OLEDs," she said. "The process can be scaled up from here, probably to six inches by six inches and larger."

Amos and her team have been synthesizing new, less expensive and more environmentally friendly quantum dots. The team has also modified the interfaces between the quantum dots and other layers of the OLED to improve the efficiency with which electrons are transferred, allowing them to produce more efficient light in the visible spectrum.

In addition to their higher efficiency, wider range of colors, and ability to be applied to flexible surfaces, Amos' QD-LEDs also use low-toxicity materials, making them potentially better for the environment.

This image shows quantum dots with conjugated polymer and ligand enhancement chemistry. Courtesy of Delaina Amos.

“Ultimately we want to have low cost, low toxicity, and the ability to make flexible devices,” she said. The team has recently demonstrated small working devices, and Amos adds that she hopes to have larger devices within the next several months.

The presentation CF1M.3., “Printed Hybrid Quantum Dot Light-Emitting Diodes For Lighting Applications” by Amos will be held at 9:15 a.m. on Friday, June 14, in the convention center.

Other Special Symposia represent a broad range of topics, such as lab-on-a-chip applications, optogenetics and optical control of biological processes, terahertz technologies, and advances in extreme-UV science and applications.

Plenary Talks

On Tuesday, June 11, beginning at 8:15 a.m., two keynote addresses will be presented by laser science luminaries. Paul Corkum, Joint Attosecond Science Laboratory, University of Ottawa and National Research Council, Canada, will speak on “Attosecond Photonics." He will be followed by Stanford University's Stephen Harris, who will present “Parametric Down Conversion Over Fifty Years: From Microwaves to X-rays.”

On Wednesday, June 12, beginning at 8:30 a.m., the plenary session will feature Pranalytica President and CEO Dr. Kumar Patel, who will discuss “QCLs Revolutionizing MWIR and LWIR Applications.”

The Business of Photonics

CLEO isn't just for scientists and researchers, however. The conference features business-focused programming, such as CLEO: Expo, June 11-13. In addition to the 300 participating companies, CLEO: Expo features show floor programming that highlights business trends and market applications.

Special Market Focus sessions on Tuesday and Wednesday highlight the latest trends in the photonics marketplace. CLEO: Market Focus provides a forum to discuss new products and emerging technologies and markets while also providing networking opportunities. A key feature of this forum will be the survey of market trends and market sector outlook in the selected areas.

Industrial Laser Outlook and Opportunities will be held on Tuesday, June 11. Moderated by Mark Douglass, vice president and a senior research analyst with Longbow Research, the panel will include Herman Chui, senior director of product marketing, Spectra-Physics, who will discuss "Industrial Laser Applications and Technologies: Trends and Impacts”; DirectPhotonics Inc. GM Silke Pflueger, who will address "Ultra-High Brightness Diode Lasers — The Next Generation of Industrial Lasers”; Trumpf Inc. Micro Processing Program Manager Sascha Weiler, who will speak on "Industrial Applications of Ultrafast Lasers”; and Time-Bandwidth CEO Kurt Weingarten, who will speak on "High-speed Micromachining with Ultrafast Lasers."

Tuesday's other Market Focus will be on Bio/Industrial Photonics Entrepreneurs. Wednesday's sessions include "Medical and Aesthetic Lasers — The Future of Light-Tissue Interactions," moderated by Laura Smoliar; "Optics & Innovation for Energy & the Environment," moderated by Oclaro Market Development Manager Rick Frost, and "Optics & Innovation for Energy & the Environment" moderated by Steve Eglash, executive director of the Energy & Environment Affiliates Program at Stanford University.

On Thursday morning, the exhibit hall will be the setting for CLEO: 2013's Technology Transfer Program, which provides a forum for entrepreneurs and researchers from startups, major universities, businesses and national laboratories to present exciting new technologies that are ready and available for commercialization.

Back by popular demand, the CLEO: Expo Technology Playground on Tuesday in the exhibit hall features hands-on demonstrations from select CLEO: Expo exhibitors. Attendees will get to interact one-on-one with products and innovations from companies including IDEX Optics and Photonics, KMLabs, Newport, Optimax, PicoLuz, Princeton Instruments and more.

For more information, visit: www.cleoconference.org