Heterogeneity investigation at the single-cell level reveals morphological and phenotypic characteristics in cell populations. In clinical research, heterogeneity has important implications in the correct detection and interpretation of prognostic markers and in the analysis of patient-derived material. Among single-cell analysis, imaging flow cytometry allows combining information retrieved by single cell images with the throughput of fluidic platforms. Nevertheless, these techniques might fail in a comprehensive heterogeneity evaluation because of limited image resolution and bidimensional analysis. Light sheet fluorescence microscopy opened new ways to study in 3D the complexity of cellular functionality in samples ranging from single-cells to micro-tissues, with remarkably fast acquisition and low photo-toxicity. In addition, structured illumination microscopy has been applied to single-cell studies enhancing the resolution of imaging beyond the conventional diffraction limit. The combination of these techniques in a microfluidic environment, which permits automatic sample delivery and translation, would allow exhaustive investigation of cellular heterogeneity with high throughput image acquisition at high resolution. Here we propose an integrated optofluidic platform capable of performing structured light sheet imaging flow cytometry (SLS-IFC). The system encompasses a multicolor directional coupler equipped with a thermo-optic phase shifter, cylindrical lenses and a microfluidic network to generate and shift a patterned light sheet within a microchannel. The absence of moving parts allows a stable alignment and an automated fluorescence signal acquisition during the sample flow. The platform enables 3D imaging of an entire cell in about 1 s with a resolution enhancement capable of revealing sub-cellular features and sub-diffraction limit details. The combination of structured illumination and light sheet fluorescence microscopy in a microfluidic integrated platform enables high throughput super-resolution imaging.

We utilized a powder-based, 3D printing technique for prototyping optical fibers. Co-doped silica rods were printed using sub-micron powders with various compositions. The rods were sleeved and drawn into fibers. Ti/Al/Er-co-doped fibers are demonstrated.

We utilized a powder-based, 3D printing technique for prototyping optical fibers. Co-doped silica rods were printed using sub-micron powders with various compositions. The rods were sleeved and drawn into fibers. Ti/Al/Er-co-doped fibers are demonstrated.

We utilized a powder-based, 3D printing technique for prototyping optical fibers. Co-doped silica rods were printed using sub-micron powders with various compositions. The rods were sleeved and drawn into fibers. Ti/Al/Er-co-doped fibers are demonstrated. 

Optical fibre consisting of a pure silicon core in silica cladding combines the advantageous properties of silicon waveguides with the convenience of optical fibre. However, the optical quality of these fibres is highly dependent on the crystalline structure and the purity of the silicon. The fabrication of these fibres requires engineering of the thermal gradients during the drawing process to ensure optimal crystallisation of the silicon. Here, we investigated the effects of draw speed and analyse the induced stresses at multiple stages in the fabrication process. The thermal exposure of the silicon while in contact with a silica cladding was found to increase the optical losses. This was attributed to the diffusion of impurities from the silica cladding into the silicon core.

We demonstrate a method for rapid prototyping of optical fibers. Silica-based glass rods were 3D printed using laser powder deposition. Different doping of the 3D printed rods is evaluated, including alumina, titania, and erbium-doped glass. The rods were subsequently used as the core material in preforms with optical fibers drawn using a laser-based draw tower. A transmission loss of 3.2 dB/m was found for a fiber with 1 wt% titania doped core and pure silica cladding. Using this fabrication method, prototyping from powder to optical fiber could be achieved within a few hours.

Silicon core fibers are a promising candidate for optoelectronic and photonic applications. Fabrication and post-processing of those fibers is thus far done without precise knowledge of the processing temperatures. Here, a simple technique is presented that allows for in-situ temperature monitoring during thermal processing of silicon core fibers. The temperature was probed across the silicon melting point and cooling rates above 3500 degrees C s(-1) were measured. The silicon core was found to be molten at a temperature of 1281 degrees C, more than 100 degrees C below the bulk silicon melting point. This is attributed to stress inbuilt to silicon core fibers during the fabrication process.

A quadrature phase-shift detection system for interferometry has been conceptualized and evaluated. The main components, a microcontroller and two photodetectors, make a versatile low-cost detection system for displacement measurements or more generally phase-change measurements. The system is capable of sampling at 5 kHz with a spatial resolution of 1 nm.& nbsp;

The optical fiber itself can function as a partially reflecting concentric cavity interferometer when transversely probed by a focused laser beam. In this study, the thermal response of the fiber heated by a CO2-laser beam was characterized by monitoring the back-scattered interference pattern. Simultaneous measurement of the Bragg wavelength shift of an inscribed, high-temperature stable fiber Bragg grating allowed for calibration of the temperature-dependent phase response of the interferometer. The presented technique allows for in-situ non-contact temperature measurements up to the glass softening point.

Silicon core optical fibres have been fabricated using an experimental draw tower based on a CO laser furnace. Fabricated fibres have achieved a submicron core size and shown a record low loss of 0.1 dBcm. Frontiers in Optics / Laser Science