Ultrafast laser technology has made it possible to achieve extremely high field intensities, above 1018 W/cm2, or alternatively, light pulses with extremely short time durations corresponding to only a few femtoseconds (10−15 s). In this high intensity regime, the laser field energy is comparable to the binding energy of an electron to an atom. One result of this highly non-perturbative atom-light interaction is the process of high-order harmonic generation (HHG). In HHG, the strong laser field first ionizes the atom. The subsequent motion of the free electron is controlled by the oscillating laser field, and the electron can reach kinetic energies many times that of the original binding energy to the atom. The high energy electron can then recollide with its parent ion, releasing a high energy photon. This process occurs for many atoms driven coherently by the same laser field, resulting in a coherent, laser-like beam of ultrafast light spanning the ultraviolet to soft X-ray regions of the spectrum.
In this thesis, I will present two major breakthroughs in the field of high harmonic generation. First, I will discuss work on quasi-phase matching of high harmonic generation, which has allowed increased conversion efficiency of high harmonic light up to the water window region of the soft X-ray spectrum (~ 300 eV) for the first time.[31] This spectral region is significant because at these photon energies, water is transparent while carbon strongly absorbs, making it a useful light source for very high resolution contrast microscopy on biological samples. Since the resolution is on order of the wavelength of the light (~ 4 nm for 300 eV), detailed structures of cells and DNA can be viewed. A table-top source of light in the water window soft X-ray region would greatly benefit biological and medical research. Second, I will present work on the generation of very high harmonic orders from ions. This work is the first to show that harmonic emission from ions is of comparable efficiency to emission from neutral atoms thereby showing that high harmonic emission is not limited by the saturation intensity, or the intensity at which the medium is fully ionized, but can extend to much higher photon energies.[30] Both results were obtained by using a waveguide geometry for HHG, allowing manipulation of the phase matching conditions and reducing the detrimental effects of ionization. The ideas from this work are expected to increase the number of applications of high harmonic generation as a light source by increasing the efficiency of the process and opening up the possibility of generating multi-keV photon energies.
As one of the founders of the Sonoma Valley Museum of Art, it was distressing to me to read the recent article regarding a proposed name change for the Museum. It was also surprising.
I am privileged with the title of “President Emeritus” for the time and effort I spent helping to organize, buy and build the Sonoma Valley Museum of Art. I served on the organizing committee, the Board of Directors, and the Advisory Council for many years. Until I received the notice of the Annual General Meeting of the SVMA, I was unaware a name change was being considered. It’s hard for me to imagine that there is “broad support” for this idea, as Linda Keaton stated in this paper last week, when no one in the general membership with whom I have spoken, including former founding board members, had any idea this was going on.
This lack of communication is truly unfortunate. The Sonoma Valley Museum of Art was formed as a “Public Benefit Not for Profit, Membership Organization”. The changes asked for by the Board require membership approval, but no rationale has been provided to the membership so that we can make an informed decision.
There is a well known organizational effect of founders believing that subsequent administrations are doing everything wrongly. I readily confess a deep affection for the SVMA, and also admit I have some differences regarding decisions that have been made since my tenure. I do realize that all organizations must continue to develop and grow, and sometimes that growth creates conflicts among well meaning individuals with differing approaches. But among the duties of all directors is to preserve the assets of the organization which they serve.
Since its inception the Sonoma Valley Museum of Art has sought to be a regional center for visual arts programming. I believe it is succeeding in that aspiration. We have drawn participant as exhibitors, as visitors and as supporters from the larger Bay Area and beyond, and have even drawn national media attention for some of our programming and planning decisions. The name has obviously NOT been a limiting factor. It is in fact a valuable asset.
Sonoma Valley enjoys a world wide reputation for its hospitality, history and appreciation of beautiful things, including wine, food, architecture and art. Jack London, Maya Angelou, MFK Fisher and many others have lived and worked here and created meaningful, significant works. It was an easy choice to make to put that pride of place into the name of the museum.
This year marks the 20th Anniversary of the founding of the SVMA and is an appropriate time to look back at how far we have come and look forward to what we can become. I do not believe it is time to shed its identity and association with Sonoma Valley.
I will be attending the Annual General Membership meeting March 15 at 5:00 PM. I will be voting NO when asked to amend the Articles of Incorporation and urge other members of the Sonoma Valley Museum of Art to do the same. If other members cannot attend but wish to retain the name, please name me as your proxy on the form provided by the museum or stop by my studio at 148 East Napa St, Sonoma and I will provide a form.