CCNY physicists develop tunable laser that spans two telecommunications windows

Physicists in the Institute for Ultrafast Spectroscopy and Lasers (IUSL) of the Physics Department at The City College of New York (CCNY) have developed new near-infrared broadband laser materials with tunability ranges around triple those of earlier crystals. The new crystals have a tunability range of as much as 460 nm and have potential application in such fields as telecommunications, biomedical imaging, and remote sensing.

"For the first time tunable laser operation was achieved at both the 1.33 μm (microns) and 1.55 μm telecommunication windows from a single optical center in trivalent chromium (Cr3+) doped LiInSiO4 (lithium iridium silicate) (Cr3+:LISO) and LiInGeO4 (lithium iridium germanate) (Cr3+:LIGO) single crystals," said Robert R. Alfano, Distinguished Professor of Science and Engineering and director of IUSL. Because of their strong optical absorption in the range of laser diode pump sources and quantum efficiency of 50%, the new materials have promise for use in miniature broadband laser devices for telecommunication industry, biomedical imaging, optical coherence tomography, laser spectroscopy, ultrafast pulse generation and remote sensing, he added.

The crystals have the widest bandwidth and the most near-infrared shifted wavelength range for laser operation ever demonstrated for the Cr3+ ion, noted Professor Alfano, who earlier this month was awarded The Optical Society of America's Charles Townes Award for his discovery of and work on the supercontinuum.

Established in 1982 by professor Robert R. Alfano, the IUSL has grown to encompass ten laboratories located in the Marshak Science Building of The City College of New York. Research and support staff now total 52. Among the major technical accomplishments are inventions of chromium-based Forsterite, Cunyite, and emerald lasers; fluorescence and excitation biopsy techniques for medical diagnostics; and optical biomedical imaging techniques.

For more information, please visit www.ccny.cuny.edu.