New Laser Design Controls Color, Intensity of Light by Varying Cavity Architecture

Lasers are used in almost all places, from light shows at concerts to checkout counters at supermarkets, and they are considered to be a much more efficient light source than incandescent bulbs. However, they are not cheap to produce.

A more cost-effective laser design has been engineered by a new Northwestern University study. This new design is capable of outputting multi-color lasing and also provides a step forward in chip-based lasers and miniaturization.  The outcomes could allow encoded, redundant, encrypted and faster information flow in optical fibers, and also multi-color medical imaging of diseased tissue in real time.

The study has been published in the July 10 issue of Nature Nanotechnology.

In our work, we demonstrated that multi-modal lasing with control over the different colors can be achieved in a single device. Compared to traditional lasers, our work is unprecedented for its stable multi-modal nanoscale lasing and our ability to achieve detailed and fine control over the lasing beams.

Teri W. Odom, Senior Author and a Charles E. and Emma H. Morrison Professor of Chemistry in the Weinberg College of Arts and Sciences, Northwestern

This research offers new insights into the mechanism and design of multi-modal nanoscale lasing based on structural engineering and manipulating the optical band structures of nanoparticle superlattices. With this technology, the Researchers will be able to control the intensity and color of the light by just varying its cavity architecture.

Nanoparticle superlattices refer to finite-arrays of metal nanoparticles assembled into microscale arrays. These superlattices incorporated with liquid gain provide a platform to access varied colors with tunable intensities relying just on the geometric parameters of the lattice.

This indeed is in contrast to the existing lasers that bounce light between two mirrors and are optimized via excessive engineering and care in order to guarantee that only one color or wavelength, is emitted. Presently in the industry, it is possible to carry out multi-color lasing output by putting together several single-color lasers. This new work offers a strategy ideal for eradicating expensive fabrication processes and that which will help in directly producing multiple, stable lasing peaks from one device.

In humans, our perception of the world would be limited if we only ‘saw’ in a single color. Multiple colors are essential for us to receive and process information at the same time, and in the same way, multi-color lasers have the potential for tremendous benefits in daily life.

Teri W. Odom, Senior Author and a Charles E. and Emma H. Morrison Professor of Chemistry in the Weinberg College of Arts and Sciences, Northwestern

Going forward, Odom stated that she and her team are keen on designing white nanolasers by covering red, green and blue wavelengths simultaneously. Their approach is expected to permit them to change the “whiteness” by controlling the relative intensity of the red, green and blue channels. Furthermore, this work also provides possibilities for ultra-sensitive sensing in chemical processes, in which varied molecules can be monitored simultaneously, and in-situ cellular imaging at multiple colors that allows different dye labels to be excited by a wide range of laser colors and varied biological processes to be correlated.

The study is titled “Band-edge engineering for controlled multi-modal nanolasing in plasmonic superlattices.” Co-corresponding Authors include George Schatz, Professor of Chemistry at Weinberg, and Dr. Richard Schaller, Assistant Professor of Chemistry at Weinberg and a Nanoscale Materials Scientist at Argonne National Laboratory. Danqing Wang, an Applied Physics Graduate Student, is First Author.

The National Science Foundation (NSF) under grant numbers DMR-1608258 and DMR-1306514 funded the research.