AS&T Fall 2009 Colloquia Series

• September 23, 2009

Speaker:   Professor David Attwood, EECS

4 PM-5 PM, Sibley Auditorium, Bechtel Engr. Center

Title: Nanoscale Soft x-ray and EUV Imaging for Microscopy and Lithography

Nanoscale imaging is approaching 10 nm for both soft x-ray microscopy and extreme ultraviolet (EUV) lithography. Soft x-ray microscopy addresses scientific issues involving nanoscale magnetism, cellular biotomography, wet environmental studies, and others, all utilizing elemental specificity. Future directions include the extension to fsec/asec dynamics, for which source development is the major issue.  EUV lithography is the leading candidate for high volume manufacturing of computer chips at the 16 nm node in 2013. At this node physical gates are expected to be 11 nm wide. While there are several significant issues, including defect-free masks and resists that simultaneously achieve resolution, sensitivity and LER , the major issue affecting insertion at the 16 nm node is the achievement of a 250 watt (collectible, in-band, spectrally clean) EUV source. In this presentation we discuss recent results and challenges for the future, for both soft x-ray microscopy (nm and fsec) and EUV lithography (2013 or later?).

David Attwood received his PhD in Applied Physics from NYU in 1972.  He was the founding Director for the Center for X-Ray Optics (LBNL) and the first Scientific Director of the Advanced Light Source at Lawrence Berkeley National Laboratory.  He has been a Professor-in-Residence at Berkeley since 1989 and is a founding member of the Applied Science & Technology PhD program.

• October 21, 2009

Professor Daniel Fletcher, BIOE

4-5 PM, Sibley Auditorium, Bechtel Engineering Center

Title:  Cantilevers, Jets, and Lenses:  Tools for Engineering Biology

Biological systems are extraordinarily complex and remarkably capable.  Even single cells exhibit behaviors that are far from being fully explained, such as crawling motility and cell division.  Progress in understanding biological systems often relies on the development of new technologies for measurement and manipulation.  In this talk, I will describe several new experimental tools that my laboratory has developed to quantify biological behavior at the molecular and cellular scale.  We have used these tools to gain a better understanding of how molecules that make up the cell’s cytoskeleton collectively generate forces for movement and shape change.  This understanding is provided insight into how cells and cell-like structures can be engineered to address therapeutic challenges.

Daniel Fletcher joined the Bioengineering Graduate Group in 2002 after earning his PhD. from Stanford the previous year.  He has since gone on to earn numerous awards including NSF's CAREER early faculty development award and becoming a White House Fellow.  Professor Fletcher, in addition to being an Associate Professor on campus, is deputy director of the Physical Biosciences division of Lawrence Berkeley National Laboratory.

• December 9, 2009

Professor Marty Banks, Optometry/Vision Science

4-5 PM, Sibley Auditorium, Bechtel Engineering Center

Title: Blur and Perceived Depth: Probabilistic Model, Experimental Data, and Possibly a New Technique for Deblurring

The pattern of blur in an image affects the apparent scale of the image’s contents. It is useful to understand how this phenomenon works and to develop algorithms that would enable image designers to manipulate depth-of-field effects in order to produce a desired apparent scale. We present a probabilistic model of how viewers could use blur and other pictorial cues to estimate the absolute and relative distances to objects in a scene. From the model, we developed a semi-automated algorithm that applies blur to a sharply rendered image and thereby changes the apparent distance and scale of the scene’s contents. To examine the correspondence between the model/algorithm and viewer experience, we conducted an experiment with human viewers and compared their estimates of absolute distance to the model’s estimates. We did this for images with geometrically correct blur and for images with commonly used approximations to the correct blur. The agreement between the experimental data and model predictions was excellent. Interestingly, the model predicts that some approximations should work well and that others should not; human viewers behaved in the same fashion as the model to the approximation. The model and algorithm allow one to manipulate blur precisely and efficiently to achieve the perception of desired scale. The model and algorithm also open the opportunity for improving techniques for deblurring images by converting the problem from blind to non-blind deconvolution.

Martin Banks earned his PhD in Developmental Psychology from the University of Minnesota in 1976.  Arriving at Berkeley in 1984, he is currently a Professor in Optometry and Vision Science, which he chaired from 1995 to 2002.  He is also affiliated with the department of Psychology.  Professor Banks's research focuses on perception of visual space, multisensory interactions, and virtual environments.