12 May 2010
Researchers from around the world will present the latest breakthroughs in electro-optics, laser science and commercial applications in photonics at the 2010 Conference on Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference (CLEO/QELS). The event will run 16–21 May at the San Jose McEnery Convention Center in San Jose, California.
Here is a round-up some of the research that will be presented:
Single-cycle infrared pulses
Scientists from the University of Konstanz in Germany will discuss how they created a single-cycle pulse with a duration of just 4.3 fs at a wavelength of around 1.3 µm. One reason for wanting shorter light pulses is that more data can be encoded within a signal lasting a certain interval of time. In essence, shorter pulses would allow more data to be sent down an optical fibre. Short pulses such as this can also serve as stroboscopic illumination for making movies of very short-lived phenomena, such as the movement and interactions of molecules.
• Presentation CWJ1, "Single-cycle light pulses from a compact Er:fibre laser" by Guenther Krauss et al., is at 4.45 p.m. on Wednesday 19 May.
Inscribing nanoscale plastic parts
In lithography, when light is used to inscribe patterns on microchips, it is well known that the features cannot get much more narrow than about a quarter of the wavelength of the light. Now however, a team from the University of Maryland, US, has shifted this boundary, achieving pattern features with a size as small as one-twentieth of the wavelength.
The researchers used two laser beams racing through a polymer solution. One beam triggers polymerization while the other beam turns the process off. Polymerization occurs in a tiny overlap region between the beams. One of the structures was a sphere-like post only 40 nm tall.
The leader of this effort, John Fourkas, says that the size of the tiny polymer structures probably represents the smallest fraction of the incoming radiation wavelength ever realized in the laboratory. If the polymer structures could be made conducting, then they could possibly be used in making microchips. More likely, Fourkas says, are applications in the area of biochemistry. Since the polymer structures are much smaller than typical cells, they might be used to study cell function.
• Presentation JTuA1, "High resolution 3-D laser direct-write patterning" by John T Fourkas et al., is at 8.00 a.m. on Tuesday 18 May.
Laser cooling of solids for sensitive sensors
Mansoor Sheik-Bahae of the University of New Mexico and colleagues are developing a laser-based technique to cool semiconductor loads. At CLEO, the group will describe a new experiment in which the temperature of a GaAs semiconductor load was lowered down to 165 Kelvin.
"This is the only solid-state technology that can reach these temperatures, the coldest that any semiconductor has gotten without the use of cryogens and/or mechanical coolers," says Sheik-Bahae. "Our goal is to try to get colder and colder, to get to 123K – the NIST-defined standard for cryogenic – and then next to 77K, the boiling temperature of liquid nitrogen. With the right laser and the right power, we know we can get to 120K."
• Presentation QFG1, "Laser cooling of a semiconductor load to 165K" by Denis Seletskiy et al., is at 10.15 a.m. on Friday 21 May.
Speeding up broadband spectroscopy
Birgitta Bernhardt, a graduate student at the Max Planck Institute for Quantum Optics in Munich, Germany, will show how two frequency comb devices running simultaneously can be used to record broadband spectra. This approach is said to speed up the task of recording a spectrum by a factor of one million compared with traditional Fourier transform spectroscopy. This dual-comb process has been tried before, but not previously at the important mid-infrared region ranging from 2 to 8 µm. Mid-infrared light is important for the characterization of the structure of matter and for a number of detection problems.
"The applications are very broad," says Bernhardt, "ranging from biomedicine (analysis of breath) to environmental monitoring or analytical chemistry (small traces of environmental and toxic vapours can be detected because of the high sensitivity of the measurement technique), and laboratory astrophysics."
• Presentation CMJ2, "2.4 µm dual-comb spectroscopy" by Birgitta Bernhardt et al., is at 8.30 a.m. on Monday 17 May.
On 16 May LaserFest will host a special symposium entitled "Retrospectives on the invention of the laser". Among the laser pioneers and experts who will speak are Charles Townes, who won the Nobel Prize for Physics in 1964 for conceptualizing the maser, the precursor to the laser, and Kathleen Maiman, whose late husband, Theodore Maiman, demonstrated the first working laser at Hughes Research Labs on 16 May 1960. Events hosted by LaserFest partners and sponsors are taking place throughout 2010. Founding partners of LaserFest are SPIE, the Optical Society (OSA), the American Physical Society (APS) and the IEEE Photonics Society.