Description
In the absence of other qualified sources, it is the intent of the National Institute of Standards and Technology (NIST) of the Department of Commerce to acquire research support for a study on "Optically Excited Chip Scale Atomic Clocks (CSACs) with Integrated Nanoresonators" from the University of Colorado in Boulder, Colorado. A. Background: The Time and Frequency Division of NIST currently has a substantial multidisciplinary research program focused on developing ultra-small atomic clocks. Smaller atomic clocks could play an important role in future commercial applications in communication and navigation systems. The goal is to reduce the size of a fully operating atomic frequency reference to below 1 cubic centimeter, while maintaining a high degree of stability. At the heart of most atomic clocks is a vapor cell, a sealed container confining an atomic vapor in a controlled environment. A major part of the research being carried out involves fabricating miniature atomic vapor cells. Miniaturization degrades the stability of an atomic clock at a fundamental level due to more frequent collisions of the atoms with the cell walls. This degradation can be mitigated with the use of a wall coating which reduces the effect of the wall collisions on the atomic coherence and enables the atoms to undergo considerably more wall bounces than would be possible with a regular glass surface. The resulting improvement in performance is one critical step in achieving the clock stability goals set by NIST. Wall coatings with low adsorption energies have been shown to be effective in extending the coherent lifetime of hyperfine-polarized atoms in the cell. In particular wax materials such as paraffin and polyethylene have allowed the atomic coherence to persist for up to 1000 bounces of the atoms on the container walls. However, with higher quality, more uniform coatings, it is likely that even longer coherent lifetimes can be obtained. In addition, it is important to find a way of applying the coatings to small-scale structures and to integrate the coating application into our cell-fabrication process. B. SCOPE: The proposed study will (1) define surfaces likely to be useful in atomic clock applications, with particular emphasis on Self-Assembled Monolayers (SAMS) and liquid crystal related materials, (2) prepare high-quality surfaces, applied to the interior walls of spherical glass bulbs provided by NIST and (3) develop a process to apply high-quality coatings to glass and silicon substrates perforated with small (sub-mm) holes. C. PERIOD OF PERFORMANCE: The period of performance consists of a one-year basic contract and a one-year option period. D. SOLE SOURCE: NIST has determined that only the University of Colorado's Ferroelectric Liquid Crystal Materials Research Center (FLC MCR) located in Boulder, Colorado can perform this research. There are four main reasons that only the FLC MCR is the only responsible source for this effort. Item 1) is the primary justification, and 2-4) outline the reasons that the Defense Advanced Research Projects Agency (DARPA), of the Department of Defense decided to fund the surface science part of the NIST project as a subcontract to CU. 1) The funding for this effort is a result of a joint proposal submitted by NIST and the University of Colorado to DARPA. It was awarded through a competitive process. Funding for the first year of this project (FY02) was transferred from NIST to the University of Colorado by a NIST purchase order. The second and third years of funding (FY03 and FY04) will be transferred through this new contract with the University of Colorado. Since DARPA selected this project for funding, it is not possible to consider anyone other than Associate Professor Maclennan at the University of Colorado. Dr. Maclennan and his colleagues in the Ferroelectric Liquid Crystal Materials Research Center (FLC MRC) at the University of Colorado in Boulder are internationally recognized experts in this field, and it is this expertise and unique skill set that helped secure funding for this proposal. 2) This effort requires a multi-disciplined team of researchers. The thin-film surfaces themselves are applied using chemical-engineering techniques, and an understanding of basic chemistry is at the heart of the self-assembly process. The interaction of the alkali atoms, which define the precise frequency of the clock, with the walls on which the thin-film surfaces are deposited requires an in-depth knowledge of the physics of the collision process. Dr. Maclennan and his colleagues at the National Science Foundation (NSF) funded Ferroelectric Liquid Crystal Materials Research Center (FLC MRC) at the University of Colorado in Boulder (CU) carry out research on liquid crystals and other self-assembled systems. They are uniquely qualified to carry out the research outlined. In addition to Dr. McLennan they have a highly multidisciplinary team composed of experts from the areas of physics, chemistry, and chemical engineering. 3) Special Resources are required for this effort. The FLC MRC is a world leader in the field and has unique capabilities, equipment (rotating anode x-ray diffractometer and the ellipsometer for x-ray and optical reflectivity studies), facilities, and most importantly the experience that is necessary for preparing and assaying the coatings. 4) Proximity to the NIST Laboratory in Boulder, Colorado: The FLC MRC is uniquely qualified because it is located in Boulder, which will facilitate the safe transfer of the samples between their lab and NIST. The special surfaces to be delivered under this contract are prepared in a highly clean environment and must be transferred to NIST without contamination to ensure that the surface will perform adequately in the NIST lab. In addition, and most importantly, it is known that the type of organic surface materials under consideration undergo aging processes that occur on a fairly quick time scale (minutes to days) and depend on their time, environment and temperature history. Therefore, it is imperative for NIST to evaluate the coatings soon after they are fabricated. The FLC MRC lab at the University of Colorado is therefore uniquely qualified to carry out this research. This notice may represent the only notice. See note 22.