Bulletin of the American Physical Society
38th Annual Meeting of the Division of Atomic, Molecular, and Optical Physics
Volume 52, Number 7
Tuesday–Saturday, June 5–9, 2007; Calgary, Alberta, Canada
Session A1: Plenary Prize Session |
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Chair: T. Gay, University of Nebraska-Lincoln Room: TELUS Convention Centre Macleod BCD |
Wednesday, June 6, 2007 8:00AM - 8:36AM |
A1.00001: Rabi Prize Talk: The Art of Light-based Precision Measurement Invited Speaker: Improvements in spectroscopic resolution have been the driving force behind many scientific and technological breakthroughs over the past century, including the invention of the laser and the realization of ultracold atoms. Maintaining optical phase coherence is one of the two major ingredients (the other being the control of matter) for this scientific adventure. Lasers with state-of-the-art control can now maintain phase coherence over one second, that is, 10$^{15}$ optical waves pass by without losing track of a particular cycle. Translating into distance, such a coherent light wave can traverse the circumference of the Earth 10 times and still interfere with the original light. The recent development of optical frequency combs has allowed this unprecedented optical phase coherence to be established across the entire visible and infrared parts of the electromagnetic spectrum, leading to direct visualization and measurement of light ripples. Working with ultracold atoms prepared in single quantum states, optical spectroscopy and frequency metrology at the highest level of precision and resolution are being accomplished. A new generation of atomic clocks using light has been developed, with anticipated measurement precision reaching 1 part in 1018. The parallel developments in the time domain have resulted in precise control of the pulse waveform in the sub-femtosecond regime, leading to demonstrations of coherent synthesis of optical pulses and generation of coherent frequency combs in the VUV spectral region. This unified time- and frequency-domain spectroscopic approach allows high-resolution coherent control of quantum dynamics and high-precision measurement of matter structure across a broad spectral width. These developments will have impact to a wide range of scientific problems such as the possible time-variation of fundamental constants and gravitational wave detection, as well as to a variety of technological applications. [Preview Abstract] |
Wednesday, June 6, 2007 8:36AM - 9:12AM |
A1.00002: Broida Prize Talk: Stable and Accurate Single-Atom Optical Clocks Invited Speaker: The potential for high stability and accuracy of optical clocks based on narrow transitions of single ions has begun to be realized [1-3]. At NIST, we have constructed and are operating two single-ion optical clocks; one based on the $^{2}$S$_{1/2}$ ($F$ = 0) $\leftrightarrow \quad ^{2}$D$_{5/2}$ ($F$ = 2, $m_{F} = 0)$ electric-quadrupole transition ($\lambda $ = 282 nm, $\nu $ = 1.064 PHz) of a single, laser-cooled $^{199}$Hg$^{+}$ ion held in a cryogenic rf Paul trap, and one based on the $^{1}$S$_{0} \quad \leftrightarrow \quad ^{3}$P$_{0}$ intercombination line ($\lambda $ = 267 nm, $\nu $ = 1.124 PHz) of a single $^{27}$Al$^{+}$ ion held in a linear trap [4]. The burden of cooling, state preparation and state detection of the Al$^{+}$ ion are borne by an auxiliary Be$^{+}$ ion using quantum logic methods [5]. In a recent comparison of these two standards, we have achieved a relative fractional frequency instability of less than 7 $\times $ 10$^{-15 }(\tau $/s)$^{-1/2}$, reaching 4 $\times $ 10$^{-17}$ in 30 000 s. We have also compared the frequency of the Hg$^{+}$ optical clock to that of the cesium fountain standard NIST-F1, for which we obtained fractional frequency inaccuracies below 10$^{-15}$. Repeated measurements of the frequency ratios of the clock transitions of all three standards provide intriguing possibilities for laboratory tests of fundamental physics, such as testing for the ``constancy'' of the fundamental constants. We will report the results of measurements conducted over the course of five years and discuss the implications of these results as a constraint to present-day temporal variation of the constants [6]. \newline \newline \textbf{References} \newline [1] H.S. Margolis \textit{et al., }Science \textbf{306}, 1355 (2004). \newline [2] T. Schneider, E. Peik, and Chr. Tamm, Phys. Rev. Lett. \textbf{94}, 230801 (2005). \newline [3] W.H. Oskay \textit{et al.}, Phys. Rev. Lett. \textbf{97}, 020801 (2006). \newline [4] P.O. Schmidt \textit{et al., }Science \textbf{309}, 749 (2005). \newline [5] D.J. Wineland \textit{et al.}, \textit{Proc. 6th Symposium on Frequency Standards and Metrology, }P. Gill, ed. (World Scientific, Singapore, 2002) pp. 361-368. \newline [6] T. M. Fortier \textit{et al.,} Phys. Rev. Lett. accepted for publication (2007). [Preview Abstract] |
Wednesday, June 6, 2007 9:12AM - 9:48AM |
A1.00003: Nanoelectronics and Plasma Processing --- The Next 15 Years and Beyond Invited Speaker: The number of transistors per chip has doubled every 2 years since 1959, and this doubling will continue over the next 15 years as transistor sizes shrink. There has been a 25 million-fold decrease in cost for the same performance. There are now as many as 1.5 billion transistors on-chip, with gate lengths as small as 37 nm (120 atoms) and oxide thicknesses as small as 1.5 nm (5 atoms). The smallest working transistor has a 5 nm (17 atoms) gate length, close to the limiting gate length, from simulations, of about 4 nm. Plasma discharges are used to fabricate hundreds of billions of these nano-size transistors on a silicon wafer. These discharges have evolved from a first generation of ``low density'' reactors capacitively driven by a single source, to a second generation of ``high density'' reactors (inductive and electron cyclotron resonance) having two rf power sources, in order to control independently the ion flux and ion bombarding energy to the substrate. A third generation of ``moderate density'' reactors, driven capacitively by one high and one low frequency rf source, is now widely used. Recently, triple frequency and combined dc/dual frequency discharges have been investigated, to further control processing characteristics, such as ion energy distributions, uniformity, and plasma etch selectivities. There are many interesting physics issues associated with these discharges; an example of electromagnetics effects will be described. Beyond the 4 nm transistor limit lies a decade of further performance improvements for conventional nanoelectronics, and beyond that, a dimly-seen future of spintronics, single-electron transistors, cross-bar latches, and molecular electronics. [Preview Abstract] |
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