This Small Business Innovation Research (SBIR) Phase II project focuses on the development, manufacturing and commercialization of a novel miniature self-aligned tunable diode laser. The tunable laser platform offers two major advantages compared to currently available products and technologies: (1) passive optical alignment and assembly; and (2) extremely broad spectral coverage from visible (375nm) to the infrared (4,000nm). The self-alignment feature translates to much simpler and efficient manufacturing, and the optical design enables the new platform to be two orders of magnitude more compact than commercially available tunable diode lasers. These features combine to considerably lower the labor costs associated with assembly and packaging. The research objectives are to determine the parameters of the passive cavity that enable (1) stable single frequency operation, (2) a linewidth less than 30KHz, and (3) less than 1MHz wavelength drift. It is also critical to develop methods to tune the output to a specific target wavelength. Prototypes of the tunable laser will be built for three wavelength groups: blue (400-415 nm) ? Red (635-660 nm) and near-infrared (760-790 nm). This novel laser platform will enable a broad range of technology areas.
The broader impact/commercial potential of this project has direct links to commercial applications that decrease energy use or promote renewable energy implementation. Specifically, this laser technology can assist the reduction of carbon emissions by monitoring and optimizing efficiencies in combustion processes such as engines and coal plants (via gas sensing with infrared tunable lasers). The technology will help accelerate the deployment of environmental sensing stations by providing the key optical source for sensing systems at a fraction of today?s cost. A second role would be to provide athermal operation of lasers, which could significantly reduce the energy consumption in telecommunication systems by eliminating the requirement for cooling the lasers. A third application would be improving the efficiency of renewable wind power (via wind sensing with blue-violet lasers) by enabling ?smart? wind turbines. A laser-based wind sensor would provide each ?smart? turbine of a wind farm with the ability to preemptively assess and accurately predict the wind load far in advance, helping improve overall turbine efficiency and utilization. This information is critical to the planning of energy supply into the power grid. All of these applications have immediate commercial potential to help reduce the World?s dependence on fossil fuels.
The primary goal of this National Science Foundation Small Business Innovation Research (SBIR) was to develop and show a path to manufacturability and commercialization of a match-box size laser system that can change its emitted light color very fast, without bulky mechanical actuators or high electrical power needs. The range of applications for such a compact laser system is large and diverse. For example, by illuminating an object with varying output colors from the laser, one can obtain the three-dimensional shape of any object located from a fraction of inches to several feet away with a cell phone camera in a matter of seconds. Applications in human-machine interface, such as gesture recognition for gaming and computer interaction, are also exciting opportunities. In another application, precision non-contact three-dimensional measurement of complex parts is an increasing need in the automobile and aircraft industries. The laser light generated from this laser system enables 3-D shapes to be measured with an accuracy equal to 1/100 the diameter of a human hair. In yet another exciting application, this laser system can be used to generate an "invisible" form of radiation that can penetrate fabrics and plastics for remote surveillance. This invisible radiation, commonly referred to as Terahertz radiation, is not harmful to humans or animals (contrary to X-rays), and when paired with a specialized detector, is capable of remotely detecting concealed weapons or drugs. The goals of this project were achieved. The match-box form factor of the laser system was demonstrated. Our testing demonstrated that the laser system can change its color (or wavelength) in 1/100,000th of a second by using the micro-mirror technology commonly found in video projectors. The generation of invisible Terahertz radiation was also demonstrated in collaboration with Emcore Corp., a commercial leader in Terahertz systems. The laser’s ruggedness was clearly demonstrated when the laser was assembled at Ondax and shipped to Emcore Corporation for successfully generating tunable Terahertz radiation over 2 THz range. A prototype laser was also shipped to Jan Hall, Physics Nobel Prize winner, who requested it for its outstanding capability. Valuable technical experience gained over the period of the project allowed Ondax to adapt the design to the specific needs of customers, resulting in several units successfully built and sold. The outstanding performance of this laser was also published in prestigious technical forums. The first work was published in a major peer-reviewed journal, Optics Express, in 2011. This was followed by a live presentation on the Terahertz radiation application at the Photonics West Conference in San Francisco, the premier Tradeshow/conference for laser technology in the world, in January, 2012. The development of this laser was also highlighted in a newsbreak from Laser Focus World, the most read periodical on photonics technology. We would like to thank Jan Hall, Physics Nobel Prize winner, and Ron T. Logan of Emcore for participating as consultants in this project, as well as program manager Juan Figueroa at the National Science Foundation SBIR program for his guidance and encouragement to push the laser system to market.
