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Optical microcavities and waveguides coupled to diamond are needed to enable efficient communication between quantum systems such as nitrogen-vacancy centers which are known already to have long electron spin coherence lifetimes. This paper describes recent progress in realizing microcavities with low loss and small mode volume in two hybrid systems: silica microdisks coupled to diamond nanoparticles, and gallium phosphide microdisks coupled to single-crystal diamond. A theoretical proposal for a gallium phosphide nanowire photonic crystal cavity coupled to diamond is also discussed. Comparing the two material systems, silica microdisks are easier to fabricate and test. However, at low temperature, nitrogen-vacancy centers in bulk diamond are spectrally more stable, and we expect that in the long term the bulk diamond approach will be better suited for on-chip integration of a photonic network.

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To determine the molecular mechanisms for cold cataract formation in the nucleus of the young mammalian lens, we have investigated the thermally reversible opacification of -crystallin solutions isolated from calf lens. Coexistence curves (plots of opacification temperature Tc versus protein concentration) were determined for the individual y-crystallin fractions II, III, and IV as well as for the unfractionated -crystallin mixtures isolated from the nucleus and cortex. The coexistence curve of yIV-crystallin is remarkably elevated above those of y4I-and yIII-crystallin and the -crystallin mixtures. The yIV-crystallin fraction is the major determinant of the opacification temperature within the whole lens or isolated cytoplasm. Quasielastic light-scattering spectroscopy of yIV-crystallin solutions indicates that above Tc there are two populations of protein aggregates of distinctly different mean size. As the temperature is lowered towards Tc, both populations increase in size. Opacification occurs when the population of large scatterers, which is composed of <0.1% protein by weight, reaches an average radius of about 20,000 A.The cytoplasm in eye lens cells contains a highly concentrated solution of lens-specific proteins, the crystallins. Their concentration increases from =250 to 400 g/liter going from cortex to nucleus, thus establishing the refractive index gradient required for proper focusing of incident light (1). The cytoplasm is normally transparent because of short-range ordering of the crystallins (2, 3). Mammalian lenses contain primarily a-crystallins (Mr 700,000-1,200,000), l3-crystallins (Mr 50,000-300,000) and -crystallins (Mr 20,000) (1,4,5). Their relative proportions vary with age and location within the lens as a result of both differential synthesis during development and selective degradation and insolubilization with aging (4-15). The lens nucleus is highly enriched in -crystallins, which are monomeric, basic proteins rich in sulfhydryl groups (8,(16)(17)(18)(19). The majority of human cataracts represent an irreversible opacification of the lens nucleus that progresses with age, a condition that is accompanied by oxidation of sulfhydryl groups, aggregation, and insolubilization of the various crystallins (4,8,13,(20)(21)(22)(23).The cold cataract phenomenon observed in most young mammalian lenses (e.g., calf, rat, and rabbit) is a convenient model system to study the relationship between nuclear opacification and -crystallin aggregation. A temperaturedependent reversible opacification can be induced in the nucleus of these young lenses (24)(25)(26)(27)(28). This behavior appears to be an intrinsic property of the concentrated mixture of crystallins, since it also can be induced in purified, membranefree cytoplasmic extracts of lens nucleus (27,(29)(30)(31)(32). Cold cataract has been modeled as a reversible phase-separation phenomenon (26)(27)(28)(29)(30)(31)(32). Upon lowering the temperature below a critical value Tc, the cytoplasm separates into protein-rich and protein-poor d...

A study of the evaporation of polystyrene sphere−H2O suspensions placed on nonwetting surfaces was conducted using a video camera and computer-imaging interface. The height, diameter, contact angle, and mass were measured as functions of time for a range of sessile drop sizes, polystyrene sphere diameters, and initial suspension concentrations. For initial concentrations of polystyrene spheres greater than approximately 8%, the drop diameter changed by less than 5%, and universal trends, independent of the sphere and droplet size, in the time dependence of the height, mass, and contact angle were observed. Those situations for which the polystyrene sphere concentration was less than approximately 8% showed a larger variation of diameter with time. For the case where the diameter remained constant, a theoretical model, which is analogous to the Landau theory of phase transitions, successfully predicts the experimental height and mass data over the entire evaporation range.