SBIR-STTR Award

This Small Business Innovation Research (SBIR) Phase I project proposes to develop a simple, single-shot, inexpensive, and complete laser-pulse measurement device for ~100ps to ~10ns pulses. While long (>10ns) pulses are easily measured, and recently developed techniques completely measure ultra-short pulses (<10ps), intermediate-length ~1ns, pulses remain only partially and roughly measurable, and, consequently, such pulses generally remain complex and unstable. This is unfortunate because most commercial pulsed lasers emit pulses in this intermediate range. The proposed measurement device extends Frequency-Resolved Optical Gating (FROG), a very successful technique for measuring the complete intensity and phase versus time of ultra-short pulses, which operates by measuring the pulse's spectrogram. The main challenge in extending FROG to much longer pulses is the generation of a many-ns delay range on a single shot - currently an unsolved problem in general. The proposed innovation solves it by tilting the input pulse by a remarkable ~89.9° without distorting it in time. As a result, one side of a ~1cm-wide beam precedes the other by over a meter. The proposed ns FROG can measure even very complex pulses and will cost about one tenth as much as the high bandwidth oscilloscopes currently used to only partially measure such pulses. The broader impact/commercial potential of this project will extend to most pulsed lasers, from Q-switched and gain-switched solid-state lasers to fiber lasers, which emit ~ns pulses and have many applications. All such applications will benefit from this device. First, ~ns-laser users will now have a device to test their laser?s performance, and it will be simple, easy to use, single-shot, and relatively inexpensive. It will be essential in attempts to coherently combine pulses from multiple fiber lasers, generally regarded as the next important step in high-power fiber-laser development. Injection-seeded Qswitched and gain-switched lasers, which endeavor to emit very clean ~ns pulses, are also in need of such a method for performance confirmation. Finally, laser engineers in general will be better able to improve the quality of ~ns-laser pulses, greatly benefitting all ~ns-pulsed-laser experiments and applications. If the spectacular progress in ultrafast lasers that occurred after complete ultra-short-pulse-measurement technology was introduced is any indication, such an inexpensive and simple device for measuring ns pulses should make a huge difference in the generation of ever more stable ~ns pulses and consequently in the many fields that use such lasers, from welding to surgery to material processing to distance measurements to remote sensing

This Small Business Innovation Research Program Phase II project proposes to develop a simple, single-shot, inexpensive, and complete laser-pulse measurement device for ~100-picosecond to ~10-nanosecond pulses. Long (>10 nanosecond) pulses are easily measured, and recently developed techniques completely measure ultrashort pulses (<10 picosecond). But intermediate-length, ~1-nanosecond, pulses remain only partially, roughly, and expensively measurable, and so generally remain complex and unstable. This is unfortunate because most laser pulses are in this intermediate range. The proposed measurement device is based on frequency-resolved optical gating (FROG), a very successful technique for measuring the complete intensity and phase vs. time of femtosecond pulses. The main challenge in extending FROG to much longer pulses is the generation of a many-nanosecond delay range on a single pulse-currently an unsolved problem in general. The proposed innovation solves it by tilting the input pulse by a remarkable ~89.99° without distorting it in time. As a result, one side of a ~1cm-wide beam precedes the other by over a meter. The proposed nanosecond FROG can completely measure even complex pulses and will cost less than one tenth as much as the high-bandwidth oscilloscopes currently used to only partially measure such pulses. The broader impact/commercial potential of this project follows from the fact that most pulsed lasers, from solid-state lasers to fiber lasers, emit pulses about a nanosecond long. They are the least stable lasers in the world, yet they have billions of dollars of applications, from materials processing to distance measurements to remote sensing to medical, military, and scientific uses. With the proposed device, nanosecond lasers will finally have a previously unavailable device to monitor their performance and to diagnose problems before expensive materials are ruined or patients are harmed. It will also be essential for combining pulses from multiple fiber lasers, generally regarded as the next important step in the development of compact and convenient high-power pulsed lasers. Finally, using this device, laser engineers in general will be better able to improve the quality of nanosecond laser pulses, thus greatly benefitting all pulsed-laser applications. If the spectacular progress in much-shorter-pulse lasers that occurred after analogous complete pulse-measurement technology was introduced there is any indication, such an inexpensive and simple device for measuring nanosecond pulses should make a huge difference in the generation of cleaner, more stable nanosecond pulses and consequently in the many fields that use such lasers