Despite mixed reviews from exhibitors on the show floor at the Conference on Lasers and Electro-Optics, Quantum Electronics and Laser Science Conference, and the Photonic Applications, Systems and Technologies Conference (CLEO/QELS & PhAST; May 4-9, San Jose, CA; 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 nonparticipants 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.
You can do it!
At the CLEO/QELS Joint Plenary Session it was noted 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 (the ETH is also known as the Swiss Federal Institute of Technology), who received the Joseph Fraunhofer Award/Robert M. Burley Prize for her contributions to the development of ultrafast lasers and semiconductor modelocking. “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 said. “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 acknowledged there is no comparison in magnitude between electromagnetic waves and gravitational waves with strain values as tiny as 10-21 for orbiting white dwarfs. He noted that, 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 ultrasmooth 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 in the audience during the Wednesday Plenary while Ian Walmsley, Hooke Professor of Experimental Physics at the University of Oxford, delivered his presentation, “Meet the Fock States: The Photon Revisited.” Walmsley took what could have been an otherwise dry topic and interspersed videos of college students debating the character of the photon over glasses of beer, striking a chord with the audience—young and old. “As the system gets more complicated, you need stronger and stronger refreshments,” was his conclusion, as he described the process of colluding herald and signal photons (quantum entanglement). Appropriately, to the question of whether photons are real, Walmsley’s video participants could only say, “Do you want another beer?”
Green photonics grow
Today, any conference on lasers and photonics wouldn’t be complete without a heavy emphasis on “green photonics”—those devices and technologies that reduce and may 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).
At the luncheon, Andrew Masters, director of marketing at Coherent (Santa Clara, CA) presented the background and technology behind Coherent’s PhAST/Laser Focus World Innovation Awardwinning product, the OPSL-577-3 optically pumped semiconductor laser for the treatment of macular degeneration.
Following Masters, a panel of “green photonics” speakers discussed how photonics technology could free us from fossil-fuel dependence. Scott Clavenna, cofounder and CEO of Greentech Media, noted 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,” he said. 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
In the technical track on nonlinear optics, Christian Spielmann, professor at the University of Jena, Germany, presented a tutorial, “High Harmonic Generation and Extreme Nonlinear Optics.” He 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 demonstration of quantum-key distribution over a distance of 100 km, in which a time-bin entangled-photon-pair source based on a periodically poled lithium niobate 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 reported by researchers at the University of Padua, Italy. 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 (see “Single-photon exchange advances Earth-to-space quantum link,” p. 25.
On the exhibit floor, Coherent launched its first fiber-based laser, Talisker, which offers 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). The Talisker will enable precision micromachining at high throughput rates with a negligible heat-affected zone at infrared (1064 nm), visible (532 nm), or ultraviolet (355 nm) wavelengths.
Postdeadline papers
Thirty-nine papers were selected from 215 CLEO/QELS Postdeadline Paper submissions. Among the highlights was 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. Yushi Kaneda of the University of Arizona (Tucson, AZ) and colleagues reported the demonstration of an efficient 200 mW continuous-wave solid-state laser emitting at 244 nm. It was based on intracavity doubling of an optically pumped 488 nm semiconductor laser. F. Albert et al. of Lawrence Livermore National Laboratory (Livermore, CA) described first light from the T-REX (Thomson-Radiated Extreme X-Ray) source of picosecond gamma-ray pulses. And Gabriel Mennert of the French Atomic Energy Commission (Le Barp, France) and colleagues and reported generation of 527 nm second-harmonic pulses at energies to 115 J with 85% efficiency in lithium borate.
The 2009 CLEO and the International Quantum Electronics Conference (IQEC, which replaces QELS every five years), or CLEO/IQEC & PhAST, will be held from May 31 to June 6, 2009, in Baltimore, MD.
