Optical packaging of microlens over UV-LED array

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Understanding and Affecting Student Reasoning About Sound Waves

Student learning of sound waves can be helped through the creation of group-learning classroom materials whose development and design rely on explicit investigations into student understanding. We describe reasoning in terms of sets of resources, i.e. grouped building blocks of thinking that are commonly used in many different settings. Students in our university physics classes often used sets of resources that were different from the ones we wish them to use. By designing curriculum materials that ask students to think about the physics from a different view, we bring about improvement in student understanding of sound waves. Our curriculum modifications are specific to our own classes, but our description of student learning is more generally useful for teachers. We describe how students can use multiple sets of resources in their thinking, and raise questions that should be considered by both instructors and researchers.Comment: 23 pages, 4 figures, 3 tables, 28 references, 7 notes. Accepted for publication in the International Journal of Science Educatio

Microfabrication of Optically Flat Silicon Micro-Mirrors for Fully Programmable Micro-Diffraction Gratings

AbstractWe have fabricated and characterized a Fully Programmable Micro-Diffraction Grating (FPMDG) with 64 silicon micro-mirrors for spectral shaping in the visible and near-infrared wavelength range. The FPMDG arrays of 50μm and 80μm wide and 700μm long silicon micro-mirrors have been fabricated in a process based on anodic bonding of an 8μm-SOI wafer and a borosilicate glass wafer. The detrimental bending of the micro-mirrors during electrostatic actuation has been minimized through separation of the mechanical and optical sections of the device. Flexures incorporating serpentine structures have been used to reduce the actuation dependence on length and thickness. Independent addressing of the micro-mirrors with negligible cross-talk and with bending of the micro-mirrors smaller than 0.14μm over 700μm have been demonstrated

Approaching expertise in facilitation of asynchronous online discussions in college courses

textThis study describes common online facilitator strategies of seven expert online facilitators and compares these facilitators' decision-making processes to general strategies and characteristics of experts in other domains. Specifically, this study focuses on how expert online facilitators decide to communicate with discussion participants for the purposes of increasing participant knowledge and skills in college-level online courses. Seven expert online facilitators -- identified by authoritative figures -- detailed their decision-making and composition process. Common facilitation strategies emerged from the interview data and contextual information. These common strategies were compared with characteristics and strategies of experts in other domains. Analysis of the data indicates that the participating facilitators: (a) share common decision-making strategies, and (b) demonstrate characteristics that align to characteristics of experts in other domains.Curriculum and Instructio