Generation of local magnetic field; application to VCSEL

International audienceIn this article, we report on the simulation and realization of a magnetic circuit allowing to apply an axial magnetic field higher than 1 T. The proposed electromagnet is used to investigate the influence of a magnetic field on the polarization behavior of a vertical-cavity-surface-emitting laser (VCSEL). A non-linear polarization behavior can be experimentally observed for currents as low as the threshold current, provided that the magnetic field is strong enough

Hypersonic phononic crystal for surface acoustic waves

International audienceA phononic crystal exhibiting a band gap in the near-gigahertz frequency range for surface acoustic waves was fabricated in a lithium niobate substrate. Reflection and transmission properties of the sample were characterized both electrically and optically, by means of embedded broadband interdigitated transducers and optical heterodyne interferometry, respectively. Measurements performed for (XZ) propagating surface waves show the existence of a band gap between 660 and 900 MHz. Optical measurements confirm that the phononic crystal behaves as a perfect mirror for waves propagating at frequencies within the band gap. Outside of the band gap, transmission can be observed for frequencies below, but also above the forbidden frequency range, hence showing that losses experienced by high frequency surface acoustic waves, i.e. for modes located beyond the sound line, can be partially overcome

Guidance of surface waves in a micron-scale phononic crystal line-defect waveguide

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Swept-source optical coherence tomography microsystem with an integrated Mirau interferometer and electrothermal micro-scanner

International audienc