Coherent x-ray generation at 2.7nm using 25fs laser pulses

We demonstrate for the first time that coherent soft-x-ray pulses at wavelengths of 2.7nm can be generated using 25fs driving pulses. High-order harmonic generation in He is used to produce the femtosecond x-ray harmonics, which exhibit discrete individual orders up to 221, followed by a continuum of unresolved harmonics which extend up to at least the 299th order, corresponding to a wavelength of 2.7nm, or an energy of 450eV. The large ionization potential of He, together with the ultrashort nature of the driving field, results in this dramatic extension of the harmonic plateau, by approximately 200 orders more than has been observed previously. We also obtain excellent agreement with theoretical predictions. © 1998 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87449/2/296_1.pd

Demonstration of a sub‐picosecond x‐ray streak camera

A novel design, magnetically focused, x‐ray streak camera was designed and tested using sub‐20 fs soft‐x‐ray pulses generated by high harmonic emission in a gas. The temporal resolution of the camera was demonstrated to be under 0.9 ps throughout the ultraviolet to soft‐x‐ray wavelength region. Our streak camera represents the fastest x‐ray detector developed to date. © 1996 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69727/2/APPLAB-69-1-133-1.pd

Faculty online learning communities: A model for sustained teaching transformation

Many physics faculty are aware of and interested in using research-based instructional strategies. However, knowledge and motivation are not sufficient to support successful and sustained adoption. To address this problem, we present a faculty online learning community (FOLC) model for educational change and describe its application (the New Faculty Workshop FOLC, NFW-FOLC) to provide a year of support to new faculty following attendance at the Physics and Astronomy New Faculty Workshop. FOLCs are an extension of the faculty learning community model. Here we present the theoretical underpinnings of the general FOLC model, the design principles of our particular NFW-FOLCs, and the learning objectives for NFW-FOLC participants. We demonstrate the efficacy of our NFW-FOLCs by analyzing postexperience interviews with participants from the first four NFW-FOLC cohorts. The primary motivation given by faculty for joining our FOLCs is to improve their teaching as they learn more about teaching strategies, get implementation help, and connect to a broader community. These motivations align with our NFW-FOLC design principles. Participants overwhelmingly report the experience was valuable and impacted them positively with the most commonly reported impacts of NFW-FOLC membership being changes in their implementation of teaching strategies, increased reflection about teaching, increased confidence as teachers, increased knowledge about teaching, benefits to their students, time saved, and gaining a resource. The reported impacts provide evidence that the NFW-FOLC is successfully meeting its goals. We argue that the reported impacts are uniquely supported by the FOLC model of professional development. We advance FOLCs as a generalizable model of professional development offering a number of advantages over traditional reform efforts as well as traditional Faculty Learning Communities

Ultrafast laser and amplifier sources

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42152/1/340-65-2-161_70650161.pd