Scientists demonstrate multibeam, multi-functional lasers

Nov 30, 2009
This is a computer rendering of one of the prototype multibeam, multi-functional lasers demonstrated by the team. The new laser emits several highly directional beams with the same wavelength near 8 microns, which requires two coherent beams: a probe beam and a reference beam. The probe beam interacts with a sample and recombines with the reference beam to reveal optical properties of the sample. A second type laser emits multiple small divergence beams with different wavelengths (9.3 and 10.5 microns) into different directions. Credit: Federico Capasso and Nanfang Yu, Harvard School of Engineering and Applied Sciences.

An international team of applied scientists from Harvard, Hamamatsu Photonics, and ETH Zürich have demonstrated compact, multibeam, and multi-wavelength lasers emitting in the invisible part of the light spectrum (infrared). By contrast, typical lasers emit a single light beam of a well-defined wavelength. The innovative multibeam lasers have potential use in applications related to remote chemical sensing pollution monitoring, optical wireless, and interferometry.

The research was led by postdoctoral researcher Nanfang Yu and Federico Capasso, Robert L. Wallace Professor of Applied Physics and Vinton Hayes Senior Research Fellow in , both at the Harvard School of Engineering and Applied Sciences (SEAS); Hirofumi Kan, General Manager of the Group at Hamamatsu Photonics; and Jérôme Faist, Professor at ETH Zürich. The findings appeared online in the October 23 issue of and will appear as a December 7 cover story.

"We have demonstrated devices that can create highly directional laser beams pointing in different directions either at the same or at different wavelengths," says Capasso. "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."

The more versatile laser is a descendant of the quantum cascade laser (QCL), invented and first demonstrated by Capasso, Faist, and their collaborators at Bell Labs in 1994. Commercially available QCLs, made by stacking ultra-thin atomic layers of semiconductor materials on top of one another, can be custom designed to emit a well -defined infrared wavelength for a specific application or be made to emit simultaneously multiple wavelengths. To achieve multiple beams, the researchers patterned the laser facet with metallic structures that behave as highly directional antennas and then beam the light in different directions.

"Having multibeam 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," explains Kan. "Profiles of these atmospheric components—as a function of altitude or location—are critically important for environmental monitoring, weather forecasting, and climate modeling."

Source: Harvard University (news : web)

Explore further: Seeking 'absolute zero', copper cube gets chillingly close (Update)

add to favorites email to friend print save as pdf

Related Stories

Building a more versatile laser

Nov 16, 2009

(PhysOrg.com) -- One of the drawbacks associated with using semiconductor lasers is that many of them can only produce a beam of a single wavelength, and can only send that beam in one direction at a time. ...

Scientists Create Quantum Cascade Laser Nanoantenna

Oct 23, 2007

In a major feat of nanotechnology engineering researchers from Harvard University have demonstrated a laser with a wide-range of potential applications in chemistry, biology and medicine. Called a quantum ...

Recommended for you

Backpack physics: Smaller hikers carry heavier loads

16 hours ago

Hikers are generally advised that the weight of the packs they carry should correspond to their own size, with smaller individuals carrying lighter loads. Although petite backpackers might appreciate the ...

Extremely high-resolution magnetic resonance imaging

16 hours ago

For the first time, researchers have succeeded to detect a single hydrogen atom using magnetic resonance imaging, which signifies a huge increase in the technology's spatial resolution. In the future, single-atom ...

'Attosecond' science breakthrough

17 hours ago

Scientists from Queen's University Belfast have been involved in a groundbreaking discovery in the area of experimental physics that has implications for understanding how radiotherapy kills cancer cells, among other things.

User comments : 0