GaAs membrane PhC lasers threshold reduction using AlGaAs barriers and improved processing.

Active suspended membranes are an ideal test-bench for experimenting with novel laser geometries and principles. We show that adding thin AlGaAs barrier near the top and bottom Air/GaAs interfaces of the membrane significantly reduces the carriers non-radiative recombinations and decreases the threshold of test photonic crystal test lasers. We review the existing literature on photonic crystal membrane fabrication and propose an overview of the significant defects that can be induced by each fabrication step.

Integration of the Rhombohedral BiSb(0001) Topological Insulator on a Cubic GaAs(001) Substrate.

Bismuth-antimony alloy (BiSb) is the first reported 3D topological insulator (TI). Among many TIs reported to date, it remains the most promising for spintronic applications thanks to its large conductivity, its colossal spin Hall angle, and the possibility to build low-current spin-orbit-torque magnetoresistive random access memories. Nevertheless, the 2D integration of TIs on industrial standards is lacking.

Magnification inferred curvature for real-time curvature monitoring.

The in situ and real-time measurement of curvature changes of optically reflecting surfaces is a key element to better control bottom-up fabrication processes in the semiconductor industry, but also to follow or adjust mirror deformations during fabrication and use for space or optics industries. Despite progresses made in the last two decades thanks to laser deflectometry-based techniques, the community lacks an instrument, easy to use, robust to tough environments and easily compatible with a large range of fabrication processes. We describe here a new method, called magnification inferred curvature (MIC), based on the determination of the magnification factor of the virtual image size of a known object created by a reflecting curved surface (the substrate) acting as a spherical mirror.

Extended cavity quantum cascade laser with cavity resonator integrated grating filter.

We report on an extended cavity quantum cascade laser based on a cavity resonator integrated grating filter (CRIGF) that acts as both cavity end-reflector and spectral selector. Stable, mode-hop free, single-mode emission around 2150 cm is obtained over large injection current ranges (more than 50 mA) with a typical threshold around 290 mA. A digital frequency tuning over more than 65 cm is obtained by changing the periodicity of the CRIGF ending the extended cavity.

Short communication: Evaluation of a foot dirtiness scoring system for dairy cows.

Lameness in dairy cattle is an important health and welfare concern directly affecting the economic benefits of farmers. Although foot dirtiness is a recognized risk factor for diseases inducing lameness, there is a lack of scoring systems that focus specifically on the foot. Therefore, the aim of this study was to evaluate the reliability of a 3-point dirtiness scoring system recently conceived for the assessment of the dirtiness present at the lower legs and claws of dairy cows.