Measurement of the 5S to 5D two-photon clock transition frequency of rubidium-85 in high vacuum.

We present a scheme to precisely resolve the unperturbed line shape of an optical rubidium clock transition in a high vacuum, by which we avoided the systematic errors of "collision shift" and "modulation shift." The spectral resolution resolved by this scheme is significantly improved such that we can use "Zeeman broadening" to inspect the stray magnetic field, through which we were able to compensate the magnetic field inside the Rb cells to be below 10- Gauss. We thus update the absolute frequency of the clock transition and propose a standard operation procedure (SOP) for the clock self-calibration.

Multilevel Optical Labeling by Spectral Luminescence Control in Nanodiamond Color Centers.

Distinguishing a multitude of optical labels is crucial to improving the spatial and temporal resolution of bioimaging. However, current multicolor imaging approaches are limited by the spectral overlap of employed fluorophores. We here discern different instances of a single optical label type through their emission intensity.

Absolute frequency of cesium 6S-6D hyperfine transition with a precision to nuclear magnetic octupole interaction.

We have determined the fundamental frequency of the cesium atom 6S-6D two-photon transition, for the first time, to our knowledge. Moreover, our high-resolution scheme made it possible to address the influence of the nuclear magnetic octupole on the hyperfine structure. We found that the octupole-interaction hyperfine constant deduced from the cesium 6D-level has a value nearly eight times larger than what has been deduced from the 6P-level.

Enhanced spectral profile in the study of Doppler-broadened Rydberg ensembles.

Combination of the electromagnetically-induced-transparency (EIT) effect and Rydberg-state atoms has attracted great attention recently due to its potential application in the photon-photon interaction or qubit operation. In this work, we studied the Rydberg-EIT spectra with room-temperature Rb atoms. Spectroscopic data under various experimental parameters all showed that the contrast of EIT transparency as a function of the probe field intensity is initially enhanced, reaches a maximum value and then decays gradually.

Radiation pressure on a biconcave human Red Blood Cell and the resulting deformation in a pair of parallel optical traps.

We calculated the three-dimensional optical stress distribution and the resulting deformation on a biconcave human red blood cell (RBC) in a pair of parallel optical trap. We assumed a Gaussian intensity distribution with a spherical wavefront for each trapping beam and calculated the optical stress from the momentum transfer associated with the reflection and refraction of the incident photons at each interface. The RBC was modelled as a biconcave thin elastic membrane with uniform elasticity and a uniform thickness of 0.

Effects of age and disc area on optical coherence tomography measurements and analysis of correlations between optic nerve head and retinal nerve fibre layer.

Background: The aim here was to investigate whether optic nerve head (ONH) parameters or retinal nerve fibre layer (RNFL) thickness correlate with age or disc area and whether the neuroretinal rim correlates with RNFL thickness.

Methods: This cross-sectional study enrolled 133 healthy subjects and analysed one randomly selected eye of each subject. All measurements of ONH parameters (including neuroretinal rim, disc and cup areas and cup-to-disc ratios) and RNFL thickness (global and quadrants) were taken by a single experienced operator using optical coherence tomography (OCT).

Intraocular pressure assessment in both eyes of the same patient after laser in situ keratomileusis.

Purpose: To measure intraocular pressure (IOP) after laser in situ keratomileusis (LASIK) in both eyes of the same patient and analyze the correlation between IOP measurement and keratometric (K) power, central corneal thickness (CCT), and laser ablation depth.

Setting: Private practice, Kaohsiung, Taiwan.

Methods: This prospective cohort study enrolled patients with myopia or myopic astigmatism.

Forces for morphogenesis investigated with laser microsurgery and quantitative modeling.

We investigated the forces that connect the genetic program of development to morphogenesis in Drosophila. We focused on dorsal closure, a powerful model system for development and wound healing. We found that the bulk of progress toward closure is driven by contractility in supracellular "purse strings" and in the amnioserosa, whereas adhesion-mediated zipping coordinates the forces produced by the purse strings and is essential only for the end stages.