APS News

Laser Science Meeting Features Beetles and Fast X-Rays

APS’s Division of Laser Science held its annual meeting in conjunction with the Optical Society of America’s Frontiers in Optics in San Jose from October 11th through the 15th. The meeting featured presentations on the latest research in optics and photonics.

Green Scarab Beetles: Invited speaker Mohan Srinivasarao from Georgia Tech presented his research showing how the iridescent scarab beetle Chrysina gloriosa selectively reflects circularly polarized light. Tiny spiral etchings in the beetle’s exoskeleton about ten nanometers in diameter cause only left-handedly polarized light to reflect, giving the beetle a shimmering green metallic luster. Biologists still aren’t entirely sure what the scarab beetle has to gain from its polarizing shell, or even if it is able itself to distinguish the difference between different handed polarizations of light.

Femtosecond X-Ray Pulses: Ultra-fast beams of X-rays can reveal details about a material’s molecular structure that optical observations can’t. Harry Ihee from KAIST in South Korea described how femtosecond pulses can show with unprecedented accuracy how the molecular bonds form and evolve over time. Steven L. Johnson from the Paul Scherrer Institut in Switzerland showed how observations of an emerging crystalline structure using these femtosecond laser pulses can yield surprising results. SLAC’s David Fritz updated attendees on the construction of the X-ray Pump Probe Instrument, due to be completed at the Linac Coherent Light Source in the fall of 2010.

Detecting Gravitational Waves: Nergis Mavalvala of MIT has been helping to develop instruments that can detect gravitational waves at the Laser Interferometer Gravitational Wave Observatory. Predicted by Einstein’s theory of relativity, gravitational waves cause an object to expand and contract as they propagate through space-time. These effects are so minuscule they usually get lost among an object’s noisy thermal vibrations. Mavalvala described how lasers can optically trap and cool large macro-sized objects to dampen out nearly all thermal vibrations to make detecting gravitational waves and also delicate quantum effects possible.

Imaging Gene Transcription: Christopher Fecko from the University of North Carolina at Chapel Hill has been able to resolve a DNA strand transcribing its genetic sequence into a corresponding RNA strand. Using multiphoton microscopy, a process where light penetrates deep into living tissue, Fecko explored movement of proteins inside the living cells of a fruit fly. The major research focus for him and his team at Chapel Hill has been to develop new and better techniques to image the inner workings of biological systems.

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Editor: Alan Chodos