Researchers at the University of Rochester are setting a new standard for generating ultra-fast laser pulses in a wider wavelength range than traditional laser sources.
In the Physics Review Letters publication, William Sherenninger, an assistant professor of optics, along with members of his laboratory, described a new device called the "stretched pulse soliton Kerr resonator" that improves the performance of ultrafast laser pulses. This work has important implications for a variety of engineering and biomedical applications, including spectroscopy, frequency synthesis, distance range, pulse generation, etc.
The device generates a femtosecond laser pulse, which is approximately femtosecond, or 2 trillionths of a second. This pulse is not subject to the physical limitations of the laser light source (called laser gain by laser scientists) and the wavelength of the light source limits.
"In short, this is the shortest pulse from a non-sourced fiber source," Renninger said.
Renninger and his research and postdoctoral team have improved the Kerr resonator, which is an exciting new method of generating femtosecond laser pulses that has become the subject of much research.
The lab has discovered a new soliton (a short pulse or local wave envelope) to hold its shape while propagating at a constant speed, thus overcoming the pulse duration challenge of other versions of Kerr resonators. The solitons produced in the Renninger device are different from the solitons in other Kerr resonators, especially the shape and behavior of the stretch pulses they produce.
Renninger said, "In a sense, it's stable. It repeats over and over, getting longer and longer, then shorter and shorter, and then longer and longer."
The researchers noted in the paper that these pulses "have a wide spectral bandwidth, with a compressed pulse duration of 210 femtoseconds, which is the shortest pulse duration observed from a fiber Kerr resonator so far."
Lead author Xue Dong is a graduate research assistant in Renninger's lab. In addition to Renninger, other co-authors include lab graduate researchers Qian Yang and Christopher Spiess, and former lab postdoctoral researcher Victor Bucklew.
This research was supported in part by the University Technology Development Fund, the University Research Award, and the National Institutes of Health.