Red, Green, and Blue Lasing
Overview
The semiconductor-based lasers that are commonplace today are powered by a mature technology that allows lasers to be compact and affordable. However, they are not able to cover the full spectrum of visible light. Colloidal quantum dots (CQDs) offer a new way forward. They can create efficient photoluminescence across a wide spectrum of light thanks to quantum effects. Arto Nurmikko has shown how to use films of CQDs to create a CQD-VCSEL laser, which represents a major step toward full-color, single-material lasers.
Market Opportunity
Quantum dots are tiny semiconductor particles that measure just a few nanometers in diameter. Because of quantum mechanics, they carry certain optical and electronic properties that could potentially make them useful in a variety of applications. In fact, CQDs are already used in electronic device displays because of their ability to create deep, saturated colors. For the same reason, CQDs are a promising technology for the creation of lasers that go beyond the limits of today’s most common variety.
Patients with CQDs offer benefits for lasers including low optical-gain thresholds and high temperature stability. As a result, CQD lasers are emerging as an appealing complement to standard semiconductor laser materials, which are ubiquitous and technologically mature but cannot cover the full visible spectrum of light. However, their use as a medium for lasers presents both practical hurdles and fundamental obstacles. Surmounting those challenges could allow for CQDs to be used a wide variety of applications and could allow for the creation of a single laser able to shine in any color.
Innovation and Meaningful Advantages
Nurmikko and colleagues have developed a better form of CQDs to create the first colloidal-quantum-dot vertical-cavity surface-emitting lasers (CQD-VCSEL). With the aid of aromatic ligands, the dots adhere together in densely packed films. Their process and the structure of their quantum dots cause light to emit at very low energy densities—an improvement of an order of magnitude compared to other attempts at CQD lasers, which had to pump energy into the dots to get them past the threshold necessary for them to emit light.
The method by Nurmikko’s team also reduces the number of “excitons” in the system. This is a form of light that is more likely to be lost as heat through a phenomenon called the Auger process. While this invention demonstrates a laser with single-exciton gain in the red, green, and blue wavelengths, leveraging this technology is a significant step toward full-color single-material lasers.
Collaboration Opportunity
We seek partners interested in licensing this innovative technology for existing companies or startups.
Principal Investigator
Arto Nurmikko, PhD
L. Herbert Ballou University Professor of Engineering, Professor of Physics
Brown University
Brown tech ID #2083
Arto_Nurmikko@brown.edu
https://engineering.brown.edu/people/arto-nurmikko
IP Information
US patent 9,373,931 is issued (06/21/2016)