Optogenetic Manipulation of Cell Migration with High Spatiotemporal Resolution Using Lattice Lightsheet Microscopy

Lattice lightsheet microscopy (LLSM) is modified with the aim of manipulating cellular behavior with subcellular resolution through three-dimensional (3D) optogenetic activation. In this study, we report a straightforward implementation of the activation source in LLSM in which the stimulating light can be generated by changing the spatial light modulator (SLM) patterns and the annual masks. As a result, a Bessel beam as a stimulation source is integrated into the LLSM without changing the optical configuration, achieving high spatiotemporal activation. We show that the energy power required for optogenetic reactions is lower than 1 nW (24 mW/cm2) and membrane ruffling can be activated at different locations within a cell with subcellular resolution. We also demonstrate guided cell migration using optogenetic stimulation for up to 6 h with 463 volume imaging without noticeable damage to cells.

Optical Configuration Effect on the Structure and Reactivity of Diastereomers Revealed by Spin Effects and Molecular Dynamics Calculations

The peculiarities of spin effects in photoinduced electron transfer (ET) in diastereomers of donor-acceptor dyads are considered in order to study the influence of chirality on reactivity. Thus, the spin selectivity—the difference between the enhancement coefficients of chemically induced dynamic nuclear polarization (CIDNP)—of the dyad’s diastereomers reflects the difference in the spin density distribution in its paramagnetic precursors that appears upon UV irradiation. In addition, the CIDNP coefficient itself has demonstrated a high sensitivity to the change of chiral centers: when one center is changed, the hyperpolarization of all polarized nuclei of the molecule is affected. The article analyzes the experimental values of spin selectivity based on CIDNP calculations and molecular dynamic modeling data in order to reveal the effect of optical configuration on the structure and reactivity of diastereomers. In this way, we succeeded in tracing the differences in dyads with L- and D-tryptophan as an electron donor. Since the replacement of L-amino acid with D-analog in specific proteins is believed to be the cause of Alzheimer’s and Parkinson’s diseases, spin effects and molecular dynamic simulation in model dyads can be a useful tool for investigating the nature of this phenomenon.

Implementation of a mobile spectrometer using a near infrared MEMS Fabry–Pérot interferometer sensor

Miniaturised MEMS-based Fabry-Pérot interferometer (FPI) spectral sensors allow the design of compact spectrometers in the near infrared (NIR) range. These small-size instruments can be used for quality control of alimentation products, sorting of plastics and fabrics in respect to the material composition or defining genuineness of goods. This article describes design details and achieved results in development of an inexpensive user friendly hand-held NIR spectrometer incorporating a MEMS-FPI sensor with the spectral range of 1550–1850 nm. Implemented electronic circuitry as well as the optical configuration of the device are discussed, used electronic components and the background for the choice of the light source are presented. Furthermore, the associated software for device operation and data visualisation is described. Achieved technical parameters of the device are discussed and illustrated by examples of acquired spectra. Shared experience in operating a MEMS-FPI sensor could be especially useful for designers targeting low-cost instruments for use by general public.

Simulated Study of High-Sensitivity Gas Sensor with a Metal-PhC Nanocavity via Tamm Plasmon Polaritons

An optical configuration was designed and simulated with a metal-photonic crystal (PhC) nanocavity, which had high sensitivity on gas detection. The simulated results shows that this configuration can generate a strong photonic localization through exciting Tamm plasmon polaritons. The strong photonic localization highly increases the sensitivity of gas detection. Furthermore, this configuration can be tuned to sense gases at different conditions through an adjustment of the detection light wavelength, the period number of photonic crystal and the thickness of the gas cavity. The sensing routes to pressure variations of air were revealed. The simulation results showed that the detection precision of the proposed device for gas pressure could reach 0.0004 atm.

Trace of evanescent wave polarization by atomic vapor spectroscopy

Various efforts have been made to determine the polarization state of evanescent waves in different structures. The present study shows the reliability of magneto-optical spectroscopy of D1 and D2 lines of rubidium metal and polarization-dependent transitions to investigate and trace the changes in the polarization state of evanescent fields during total internal reflection over different angles. For this purpose, we design and fabricate atomic- evanescent Rb vapor cells and examine the effect of polarization changes of evanescent waves, depending on the propagation direction of evanescent waves in anisotropic rubidium vapor media under 88 mT external magnetic field by different configurations theoretically and experimentally. The results confirm the dependency of allowed $$\sigma^{ \pm } { }\;{\text{and}}\;\pi$$ σ ± and π transitions on the magneto optical configuration as a tool to determine changes in the polarization of evanescent waves in more complicated wave states in anisotropic media.

Trace of evanescent wave polarization by atomic vapor spectroscopy

Various efforts have been made to determine the polarization state of evanescent waves in different structures. The present study shows the reliability of magneto-optical spectroscopy of D1 and D2 lines of rubidium metal and polarization-dependent transitions to investigate and trace the changes in the polarization state of evanescent fields during total internal reflection over different angles. For this purpose, we design and fabricate atomic evanescent Rb vapor cells and examine the effect of polarization changes of evanescent waves, depending on the propagation direction of evanescent waves in anisotropic rubidium vapor media under different external magnetic field configurations theoretically and experimentally. The results confirm the dependency of allowed transitions on the magneto optical configuration as a tool to determine changes in the polarization of evanescent waves in more complicated wave states in anisotropic media.

Crossbill: an open access single objective light-sheet microscopy platform

We present an open access scanned oblique plane microscopy platform Crossbill. It combines a new optical configuration, open hardware assembly, a systematic alignment protocol, and dedicated control software to provide a compact, versatile, high resolution single objective light-sheet microscopy platform. The demonstrated configuration yields the most affordable sub-micron resolution oblique plane microscopy system to date. We add galvanometer enabled tilt-invariant lateral scan for multi-plane, multi-Hz volumetric imaging capability. A precision translation stage extends stitched field of view to centimeter scale. The accompanying open software is optimized for Crossbill and can be easily extended to include alternative configurations. Using Crossbill, we demonstrate large volume structural fluorescence imaging with sub-micron lateral resolution in zebrafish and mouse brain sections. Crossbill is also capable of multiplane functional imaging, and time-lapse imaging. We suggest multiple alternative configurations to extend Crossbill to diverse microscopy applications.

The lower energy diffraction and scattering side-bounce beamline for materials science at the Canadian Light Source

A new diffraction beamline for materials science has been built at the Canadian Light Source synchrotron. The X-ray source is an in-vacuum wiggler with a 2.5 T peak magnetic field at 5.2 mm gap. The optical configuration includes a toroidal mirror, a single side-bounce Bragg monochromator, and a cylindrical mirror, producing a sub-150 µm vertical × 500 µm horizontal focused beam with a photon energy range of 7–22 keV and a flux of 1012 photons per second at the sample position. Three endstations are currently open to general users, and the techniques available include high-resolution powder diffraction, small molecule crystallography, X-ray reflectivity, in situ rapid thermal annealing, and SAXS/WAXS. The beamline design parameters, calculated and measured performance, and initial experimental results are presented to demonstrate the capabilities for materials science.

Spin-decoupled metasurface for simultaneous detection of spin and orbital angular momenta via momentum transformation

With inherent orthogonality, both the spin angular momentum (SAM) and orbital angular momentum (OAM) of photons have been utilized to expand the dimensions of quantum information, optical communications, and information processing, wherein simultaneous detection of SAMs and OAMs with a single element and a single-shot measurement is highly anticipated. Here, a single azimuthal-quadratic phase metasurface-based photonic momentum transformation (PMT) is illustrated and utilized for vortex recognition. Since different vortices are converted into focusing patterns with distinct azimuthal coordinates on a transverse plane through PMT, OAMs within a large mode space can be determined through a single-shot measurement. Moreover, spin-controlled dual-functional PMTs are proposed for simultaneous SAM and OAM sorting, which is implemented by a single spin-decoupled metasurface that merges both the geometric phase and dynamic phase. Interestingly, our proposed method can detect vectorial vortices with both phase and polarization singularities, as well as superimposed vortices with a certain interval step. Experimental results obtained at several wavelengths in the visible band exhibit good agreement with the numerical modeling. With the merits of ultracompact device size, simple optical configuration, and prominent vortex recognition ability, our approach may underpin the development of integrated and high-dimensional optical and quantum systems.