Research reigns supreme at CLEO/QELS & PhAST

SAN JOSE, CA—Despite mixed reviews from exhibitors on the show floor at the May 4–9, 2008 Conference on Lasers and Electro-Optics (CLEO), Quantum Electronics and Laser Science (QELS) Conference, and the Photonic Applications, Systems and Technologies (PhAST) Conference (collectively known as CLEO/QELS & PhAST and sponsored by APS, IEEE LEOS, and the OSA), the research community benefited from a record number of 2342 paper submissions that were narrowed down to more than 1900 tech

SAN JOSE, CA—Despite mixed reviews from exhibitors on the show floor at the May 4–9, 2008 Conference on Lasers and Electro-Optics (CLEO), Quantum Electronics and Laser Science (QELS) Conference, and the Photonic Applications, Systems and Technologies (PhAST) Conference (collectively known as CLEO/QELS & PhAST and sponsored by APS, IEEE LEOS, and the OSA), the research community benefited from a record number of 2342 paper submissions that were narrowed down to more than 1900 technical presentations in 247 technical sessions covering all things laser and quantum related.

Contrasting these figures to last year’s 1800 presentations, it isn’t hard to figure out that a growing technical conference means less time for attendees on the show floor. That said, many of the 350 exhibitors (compared to 250 last year) were amazed not by the quantity, but by the quality of leads they received. While the economy and fears of recession are making buyers cautious, fewer “looky lous” may be translating to more solid, qualified leads.

But the mixed reviews from exhibitors cannot diminish the fact that CLEO has always been an international conference for researchers, with 5300 registered attendees compared to 5200 last year. Many of the special events and technical sessions were standing-room only, such as the special Maiman Symposium on Sunday night (see page 2 for a separate report).

You can do it!

It was surprising to learn in the Wednesday morning CLEO/QELS Joint Plenary Session that 63% of the technical presentations were from companies and individuals outside the U.S. The international flavor of the conference and the importance of research was summed up well in the Plenary by Ursula Keller, head of research for the Institute for Quantum Electronics at ETH Zurich, who was presented the Joseph Fraunhofer Award/Robert M. Burley Prize for her contributions to the development of ultrafast lasers and semiconductor mode locking. “Now they know why mommy is always away,” she said to her children in the audience. When she moved from Switzerland to Stanford University for research, Keller said she was energized by the spirit at Stanford: “Nobody said I can’t do it,” she told the crowd, and added, “Consider doing science and having a family—you can do it, just try harder!”

Such a “can do” spirit was evidenced in the Monday evening CLEO Plenary presentation by University of Florida physics professor David Reitze, spokesperson of the Laser Interferometer Gravitational-Wave Observatory (LIGO) Scientific Collaboration (www.ligo.org). Reitze acknowledges there is no comparison between electromagnetic waves and gravitational waves with strain values as tiny as 10exp(-21) for orbiting white dwarfs. While you could argue that the ultimate detection of gravity waves (a tremendous feat in itself) won’t solve world hunger, the technology being developed to measure such small parameters with the world’s largest interferometer, such as large-scale vibration isolation and ultra-smooth optical surfaces, will likely contribute to many emerging applications in a variety of industries.

The excitement of exploring new frontiers is what photonics is all about, and could be seen on the faces of the New Focus Student Award entrants that sat just in front of me during the Wednesday Plenary while Ian Walmsley, Hooke Professor of Experimental Physics at the University of Oxford, uniquely delivered his presentation “Meet the Fock States: The Photon Revisited.” Taking what could have been an otherwise dry topic and interspersing videos of college students debating the character of the photon over glasses of beer surely struck a chord with the audience—young and old. “As the system gets more complicated, you need stronger and stronger refreshments,” was the conclusion of Walmsley as he described the process of colluding herald and signal photons (quantum entanglement). Appropriately, to the question of whether or not photons are real, Walmsley’s video actors could only say, “Do you want another beer?”

Green photonics grow

Today, any conference on lasers and photonics just wouldn’t be complete without a heavy emphasis on “green photonics”—those devices and technologies that reduce and can someday eliminate our dependence on fossil fuels and produce negligible environmental impact—such as photovoltaic cells and energy-efficient LEDs. And this year’s CLEO/QELS & PhAST conference was no exception. Specifically, the PhAST program featured sessions on organic LED (OLED) technology and business growth as well as laser applications in the photovoltaics market, while the press luncheon (an excellent indicator of what’s “hot” in photonics) focused on “Optics in Energy Efficiency” with speakers from Greentech Media (Cambridge, MA), the Fraunhofer Institute for Solar Energy Systems (Freiburg, Germany), Samsung SDI (Suwon, Korea), and the U.S. Department of Energy/Sentech (Washington, DC).

After the first presentation from director of marketing Andrew Masters of Coherent (Santa Clara, CA), who presented the background and technology behind his PhAST/Laser Focus World Innovation Award-winning product, the OPSL-577–3 optically pumped semiconductor laser for the treatment of macular degeneration (see complete story on page 3), the “green photonics” speakers presented their views on how photonics technology can free us from fossil-fuel dependence.

Co-founder and CEO of Greentech Media Scott Clavenna made it clear that something must be done to prevent atmospheric carbon dioxide levels from reaching the anticipated 850 ppm by 2050, “Unless you like sailing around the Arctic circle.” Clavenna and the other speakers pointed to solar photovoltaics, water purification using optics and light, and OLED displays and LED lighting as possible means to achieve a 500 ppm interim goal; however, each speaker cautioned that much more research is needed before these technologies can be cost-competitive in the marketplace.

Technical sessions and new products

In the technical track on nonlinear optics, Christian Spielmann, professor at the University of Jena, Germany, gave a tutorial on “High Harmonic Generation and Extreme Nonlinear Optics.” The talk reviewed results of years of research investigating crystal-to-liquid state changes, in which the goal is to determine transition times and identify intermediate states. Ultrashort X-ray pulses are used to follow these dynamics. “Nonlinear short-wavelength generation can be used to generate low-order harmonics, high-harmonic generation, and relativistic nonlinear effects,” said Spielmann, enabling quasi-phase matching and ultimately, the calculation of the distance between atoms.

In a track on Quantum Cryptology, Toshimori Honjo of NTT/CREST in Japan presented the results of his successful demonstration of quantum key distribution over a distance of 100 km. In his “Entanglement-Based BBM92 QKD Experiment Using Superconducting Single Photon Detectors,” a time-bin entangled photon pair source based on a periodically poled lithium niobate (PPLN) waveguide generated a 16-kbit sifted key with a quantum-bit error rate of 6.9%.

The detection of a single photon fired from an Earth-based system to an orbiting satellite and back was accomplished by researchers at the University of Padua, Italy. Professor Paolo Villoresi and his team were able to identify that the photon detected was the same individual photon originally emitted. Such a system is a significant step toward the realization of a quantum communication channel and demonstrates that laser-ranging systems can be adapted to quantum communications.

On the exhibit floor, Coherent launched the Talisker, offering high-power picosecond output in a rugged industrial package—18 W of average power at a pulse repetition rate of 200 kHz (with a pulsewidth less than 15 ps). As the first fiber-based laser from Coherent, the Talisker will enable precision micromachining at high throughput rates with a negligible heat-affected zone in infrared (1064 nm), visible (532 nm), or ultraviolet (355 nm) wavelengths.

Post-deadline papers

From 215 CLEO/QELS Postdeadline Paper submissions, 39 papers were selected. Highlights included: (1) The first report of a negative refractive index in a three-dimensional sample of an optical metamaterial, by Jason Valentine and colleagues of the University of California at Berkeley (Berkeley, CA). It used 21 alternating layers of silver and magnesium fluoride in a fishnet structure; (2) Demonstration of an efficient 200 mW continuous-wave solid-state laser emitting at 244 nm by Yushi Kaneda of the University of Arizona (Tucson, AZ) and colleagues. It was based on intracavity doubling of an optically pumped 488 nm semiconductor laser; (3) First light from the T-REX (Thomson-Radiated Extreme X-Ray) source of picosecond gamma ray pulses at the Lawrence Livermore National Laboratory (Livermore, CA), described by F. Albert et al. of Livermore; and (4) Generation of 527-nm second harmonic pulses at energies to 115 J with 85% efficiency in lithium borate by Gabriel Mennert of the French Atomic Energy Commission (Le Barp, France) and colleagues.

The 2009 CLEO and the International Quantum Electronics Conference (IQEC, which replaces QELS every 5 years), or CLEO/IQEC & PhAST, is scheduled for 5/31 to 6/5 in Baltimore, MD.

—Gail Overton, Valerie Coffey, Jeff Hecht

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