Current Seminars
​​Thursday, September 10, 2015
​3:30 p.m. reception in Dow Science Complex 208
​4:00 p.m. seminar in Dow Science Complex 107
Understanding the origin of the elements is one of the major challenges of modern astrophysics. Elements along the bottom two-thirds of the periodic table---including arsenic, selenium, barium, europium, lead, thorium, uranium, and others---are mainly produced by neutron-capture reactions. Some had not been detected previously in stars useful for probing the nucleosynthetic fossil record, and their origins are not fully understood at present. My work focuses on abundances derived from high-resolution spectroscopic data of ancient stars. I will present recent observations of these elements that muddy our understanding of when and how they were first produced in the early Universe.
Thursday, September 24, 2015 - Autumnal Equinox Lecture
​2:30 p.m. reception and poster session in Baber Room
​4:00 p.m. seminar in the Park Library Auditorium
Thursday, October 15​, 2015
​3:30 p.m. reception in Dow Science Complex 208
​4:00 p.m. seminar in Dow Science Complex 107
Thursday, October 22, 2015
​3:30 p.m. reception in Dow Science Complex 208
​4:00 p.m. seminar in Dow Science Complex 107
Thursday, November 19, 2015
​3:30 p.m. reception in Dow Science Complex 208
​4:00 p.m. seminar in Dow Science Complex 107
Since its first experimental demonstration 3 decades ago, X-ray and EUV lasers were associated to large facilities, low photon fluxes and very low repetition rates.  These limitations posed a major impediment for the effective utilization of these sources in applications.  However the development of compact (table top) extreme ultraviolet and soft X-ray lasers in the last two decades overcome these restrictions and opened the possibility of multiple practical applications in science and technology.   In this talk I will describe two of these applications: coherent lithography and high resolution EUV holography.

We utilized a table top EUV laser emitting at 46.9 nm to implement a lithographic method based on Talbot imaging.  The characteristic of this approach is that enables the fabrication of periodic nanostructures with arbitrarily complex design.  Furthermore, a main advantage of this approach is that is the lithographic step is by nature "defect free".  Examples of structures fabricated with this method with feature sizes down to 40nm will be presented.

Also, the compact EUV laser allowed the implementation of a high-resolution holographic imaging system.  A Fourier holography set up enabled the recording of holograms of sub-micron cantilevers, oscillating at MHz frequencies with 120nm spatial resolution and 1 ns temporal resolution.  These "flash" holograms were combined to compose a "movie" of sub-micron oscillating pillars.  Additionally, by properly processing the data in the reconstruction of the holograms it is possible to retrieve the position of the pillar in the three dimensions, allowing a complete characterization of the oscillation on the nano-pillar.​

Thursday, December 3, 2015
​3:30 p.m. reception in Dow Science Complex 208
​4:00 p.m. seminar in Dow Science Complex 107
Thursday, December 10, 2015
​3:30 p.m. reception in Dow Science Complex 208
​4:00 p.m. seminar in Dow Science Complex 107
​To subscribe to the email list of current seminars in physics, please send a message to listserv@ls2.cmich.edu with only the text SUBSCRIBE PHYSEMIN in the body of the message, or contact Juan Peralta at juan.peralta@cmich.edu
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