This Small Business Innovation Research (SBIR) Phase I project makes significant advances in the field of photonics by developing a cutting-edge performance, cost effective and compact ultrafast laser light amplifier. The amplifier is a key element in generating this compelling form of light for revolutionary materials processing capabilities. Ultrafast lasers enable athermal ablation of nearly any material with micron-scale precision. Historically, ultrafast lasers have been confined to bulky, optical breadboard systems?ideal for academic environments but unsuitable for practical commercial applications owing to their ambient temperature sensitivity and tendency to drift out of alignment. The technology developed under this SBIR leverages novel laser amplifier glass material development to support a planar waveguide amplifier architecture. When combined with recent advances in fiber-optic ultrafast laser technology, the herein developed amplifier module will produce a high power, compact, and cost efficient ultrafast laser integrated system. In addition, the advances made in planar waveguides under this program have utility in compact, high performance long pulse and continuous wave lasers. The technology will advance the state of the art in photonics to yield cheap, efficient and rugged amplifier architectures which can be used in a variety of applications.
The broader impact/commercial potential of this project is to provide a pragmatic architecture for ultrafast lasers which enables discovery and the application of this light in the commercial marketplace. The inherent capability for the short bursts of light from ultrafast lasers to ablate any material?including novel glasses, noble metals, modern alloys, polymers, and other hard-to-machine materials?will create substantial value by enabling a new generation of manufacturing techniques, products and services, and the businesses to drive these innovations. As a salient example, ultrafast lasers are capable of cutting and shaping bio-absorbable polymers, such as poly(lactic-co-glycolic acid) (PLGA), now in development for the next generation of cardiovascular stents. These slowly dissolve in the human body in order to avoid complications from restenosis. PLGA is extraordinarily difficult to machine with conventional lasers?due to melting?or mechanical techniques?due to loss of structural integrity. Other examples include precise, efficient cutting of organic light emitting diode (OLED) substrates and precision thin film removal for high efficiency, large area solar panels. This technology will broadly impact business processes in multiple industries by advancing manufacturing fidelity-to-design and by making obsolete the incumbent defect removal methods such as hot acid etching.
In conducting this NSF SBIR project, Raydiance has developed a compact and reliable waveguide amplifier technology to enable commercialization into a high power, industrial, ultrashort pulse laser system. In the initial phases of the program, numerous samples of waveguide gain media were produced and evaluated to identify a path to a true leap in pump-to-signal efficiency. These samples made use of novel glass compositions, multiple doping concentration levels, and variations in the waveguide geometry. At the outset, the intent was to investigate the feasibility of a planar waveguide structure. The data obtained, however, soon indicated that the technologies evaluated could lead to an advanced amplifier in a fiber format, thus sidestepping the implementation challenges of the planar geometry. Efforts then focused on understanding the fundamentals of these novel fibers, both experimentally and theoretically. The result obtained identified an opportunity to commercialize an amplifier module that made use of this new fiber technology, having a large pump to signal overlap, and a high rare earth ion doping concentration. The pump-to-signal efficiency achieved with the highly doped fiber amplifier more than doubles that produced by the current state of the art for high energy, ultrashort pulse amplifiers. These amplifiers will provide a path to increase the average power output from a Raydiance commercial laser system and require lower power pump lasers, all while being approximately 10% of the length of a more standard high power booster waveguide. The module that was designed under this contract facilitates the thermal management needs of a commercial laser system as well as providing easy integration into the Raydiance’s next generation ultra short pulse laser platform. The Raydiance Version 4.0, 20 W laser will primarily be sold as part of an integrated workstation that incorporates precision motion control, part handling, vision system, and software control of the micromachining process. Together, these elements form manufacturing solutions to further the needs of our customers, and enable new production capabilities. To properly commercialize the amplifier technology under review into a 20 W system, Raydiance has conducted extensive market research and performed system level simulations of the chirped pulse amplification (CPA) system performance as part of this SBIR Phase II program. Through these exercises, a detailed list of specifications has been produced which defines, without over-defining, the requirements of an advanced amplifier for Raydiance’s future commercial products. The laser product performance enhancements resulting from this technology will provide broader accessibility to ultrashort pulse laser solutions to end users resulting in substantial decreases in fabrication process cycle times. This is a top requirement for customers as they look to maximize their return on investment (ROI) in moving to ultrashort pulse laser processing technology.
