Method for characterizing self-assembled monolayers as antirelaxation wall coatings for alkali vapor cells

We describe a method for characterizing self-assembled monolayers (SAMs) in terms of their performance as antirelaxation wall coatings for alkali atom vapor cells. A combination of initial surface analysis and subsequent laser spectroscopy is used to provide insight into the quality of the coating, as well as its performance under the exposure to alkalis as it occurs, for example, when used in applications such as atomic magnetometers or clocks. Fused silica plates coated with octadecyltrichlorosilane SAMs were used to make cubic R87b gas cells. The surface was characterized by x-ray diffraction, contact angle measurements, and atomic force microscopy. Measurements of hyperfine resonance linewidths and frequency shifts show that the rubidium vapor atoms collide up to 40 times with the walls of the cells before their coherence relaxes and their adsorption energy is around 0.065 eV. Chemical analysis of the cell indicates some weak reactions between the coating and the rubidium atoms.

[1]  J. Kitching,et al.  Magnetometry with millimeter-scale antirelaxation-coated alkali-metal vapor cells , 2005, physics/0511003.

[2]  J. Kitching,et al.  A microfabricated atomic clock , 2004 .

[3]  D. F. Kimball,et al.  Nonlinear magneto-optical rotation with frequency-modulated light in the geophysical field range , 2002, physics/0602109.

[4]  A. Wolf,et al.  A Study of Alkyl Chain Conformational Changes in Self-Assembled n-Octadecyltrichlorosilane Monolayers on Fused Silica Surfaces , 2001 .

[5]  C. Wieman,et al.  STUDY OF WALL COATINGS FOR VAPOR-CELL LASER TRAPS , 1994 .

[6]  B. Jaduszliwer,et al.  Alkali reactions with wall coating materials used in atomic resonance cells , 1987 .

[7]  J. Camparo.  Alkali 〈I⋅S〉 wall relaxation in dichlorodimethylsilane coated resonance cells , 1987 .

[8]  J. Brossel,et al.  Relaxation of Optically Pumped Rb Atoms on Paraffin-Coated Walls , 1966 .

[9]  A. Ulman,et al.  Formation and Structure of Self-Assembled Monolayers. , 1996, Chemical reviews.

[10]  Svenja Knappe,et al.  Chip-scale atomic magnetometer , 2004 .

[11]  David L. Allara,et al.  An Intrinsic Relationship between Molecular Structure in Self-Assembled n-Alkylsiloxane Monolayers and Deposition Temperature , 1994 .

[12]  David L. Angst,et al.  Moisture absorption characteristics of organosiloxane self-assembled monolayers , 1991 .

[13]  Valerio Biancalana,et al.  Light-induced diffusion and desorption of alkali metals in a siloxane film: theory and experiment , 1999 .

[14]  A. Segmüller,et al.  Coverage of Si substrates by self-assembling monolayers and multilayers as measured by IR, wettability and X-ray diffraction☆ , 1985 .

[15]  Daniel Kleppner,et al.  THEORY OF THE HYDROGEN MASER , 1962 .

[16]  Jacques Vanier,et al.  Relaxation and frequency shifts in the ground state of Rb 85 , 1974 .

[17]  Svenja Knappe,et al.  Miniature vapor-cell atomic-frequency references , 2002 .

[18]  Hugh Robinson,et al.  Rb O-O hyperfine transition in evacuated wall-coated cell at melting temperature , 1987 .

[19]  G. Wallis,et al.  Field Assisted Glass‐Metal Sealing , 1969 .

[20]  J. Vanier,et al.  On hyperfine frequency shifts caused by buffer gases: Application to the optically pumped passive rubidium frequency standard , 1982 .

[21]  A. Pazgalev,et al.  Theory of double resonance magnetometers based on atomic alignment , 2006, physics/0605234.

[22]  Hugh Robinson,et al.  Narrow 87Rb hyperfine‐structure resonances in an evacuated wall‐coated cell , 1982 .

[23]  A. Ulman,et al.  Incorporation of phenoxy groups in self-assembled monolayers of trichlorosilane derivatives. Effects on film thickness, wettability, and molecular orientation. , 1988, Journal of the American Chemical Society.

[24]  W Happer,et al.  Push-pull optical pumping of pure superposition states. , 2004, Physical review letters.

[25]  Yue An,et al.  A novel colloid probe preparation method based on chemical etching technique , 2006, Journal of Zhejiang University SCIENCE B.

[26]  D. Guzonas,et al.  Characterization of silica surfaces hydrophobized by octadecyltrichlorosilane , 1994 .

[27]  Wasserman,et al.  X-ray specular reflection studies of silicon coated by organic monolayers (alkylsiloxanes). , 1990, Physical review. B, Condensed matter.

[28]  W. J. Cummings,et al.  Silane coatings for laser-driven polarized hydrogen sources and targets , 1997 .

[29]  N. Larsen,et al.  Effect of Solvents and Concentration on the Formation of a Self-Assembled Monolayer of Octadecylsiloxane on Silicon (001) , 2003 .

[30]  S. J. Seltzer,et al.  Synchronous optical pumping of quantum revival beats for atomic magnetometry , 2007 .

[31]  Robert Wynands,et al.  Precision spectroscopy with coherent dark states , 1999 .

[32]  J. Kitching,et al.  Atomic vapor cells for chip-scale atomic clocks with improved long-term frequency stability. , 2005, Optics letters.

[33]  R. Brewer.  Study of Atom—Wall Collisions by Optical Pumping , 1963 .

[34]  S. Mirji.  Adsorption of octadecyltrichlorosilane on Si(100)/SiO2 and SBA-15 , 2006 .

[35]  J. Kitching,et al.  Microfabricated alkali atom vapor cells , 2004 .