14 DAY TRIAL // Scientists from the Harvard University, Hamamatsu Photonics, and ETH Zurich, in Switzerland, recently demonstrated multi-beam, multi-functional lasers for the first time. The compact device emits light in the infrared wavelength spectrum, and is able to take on multiple applications at the same time. The experts underline the fact that typical lasers only emit light of a certain, well defined wavelength. A large number of applications could soon become available thanks to the innovation, including remote chemical sensing, pollution monitoring, optical wireless communications, and interferometry.
Details of the recent accomplishment have been published in the October 23 online issue of the respected scientific journal Applied Physics Letters, and has been honored with being chosen as the December 7 cover story on the same publication. The investigation was led by postdoctoral researcher Nanfang Yu, working together with Federico Capasso, the Harvard Wallace Professor of Applied Physics, and also a Vinton Hayes Senior Research Fellow in Electrical Engineering. Both experts are based at the university's School of Engineering and Applied Sciences (SEAS).
Hamamatsu Photonics Laser Group General Manager Hirofumi Kan and ETH Zurich professor Jerome Faist were also involved in the study. “We have demonstrated devices that can create highly directional laser beams pointing in different directions either at the same or at different wavelengths. This could have major implications for parallel high-throughput monitoring of multiple chemicals in the atmosphere or on the ground and be used, for example, for studying hazardous trace gases and aerosols, monitoring greenhouse gases, detecting chemical agents on the battlefield, and mapping biomass levels in forests,” Capasso explains.
The new work builds on accomplishments made in 1994 by Capasson and colleagues, who demonstrated the quantum cascade laser (QCL) while working at the Bell Laboratories. In the new study, the ultra-thin atomic layers of semiconductor materials that make up the basis of QCL were augmented by adding metallic structure patterns on the laser facet of the previous device. This allowed for the instrument to deliver light in several beams at the same time.
“Having multi-beam and multi-wavelength options will provide unprecedented flexibility. The ability to emit multiple wavelengths is ideal for generating a quantitative map of the concentration of multiple chemicals in the atmosphere. Profiles of these atmospheric components – as a function of altitude or location – are critically important for environmental monitoring, weather forecasting, and climate modeling,” Kan says.