Helical dichroism to resolve enantiomers using twisted light carrying only optical orbital angular momentum.

No abstract

Non-reciprocal asymmetric transmission, i.e., the dependence of optical transmittance on the direction of light propagation in the material, can be used in optical isolators or photonic circuits. Broadband asymmetric transmission is observed in near-field coupled aggregates of small plasmonic nanoparticles, even for unpolarized light. Non-reciprocity is demonstrated and, using a phenomenological model, induced electric quadrupole moments are identified as the root cause of the effect.

Abstract:To utilize iron oxide nanoparticles in biomedical applications, a sufficient magnetic moment is crucial. Since this magnetic moment is directly proportional to the size of the superparamagnetic nanoparticles, synthesis methods of superparamagnetic iron oxide nanoparticles with tunable size are desirable. However, most existing protocols are plagued by several drawbacks. Presented here is a one-pot synthesis method resulting in monodisperse superparamagnetic iron oxide nanoparticles with a controllable size and magnetic moment using cost-effective reagents. The obtained nanoparticles were thoroughly characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) measurements. Furthermore, the influence of the size on the magnetic moment of the nanoparticles is analyzed by superconducting quantum interference device (SQUID) magnetometry. To emphasize the potential use in biomedical applications, magnetic heating experiments were performed.

Advanced applications in optics, for example, Faraday isolators, demand for complex magneto‐plasmonic nanostructures which exhibit large Faraday rotation. These structures is fabricated by a Layer‐by‐Layer approach, albeit this being a slow technique. Here, the ultrasonic spray coating as a promising alternative method toward the formation of hybrid magneto‐plasmonic structures is pioneered by the authors. Ultrasonic spray coating is a stable, fast, and tunable mass production method applied in this work to deposit gold and iron oxide nanoparticles. Altering multiple deposition parameters give the spray coating technique a large amount of control over the coverage. Optical and magneto‐optical properties, layer formation and surface coverage of single and hybrid layers with increasing thickness and number of layers are studied and compared to samples synthesized by Layer‐by‐Layer deposition. Ultrasonic spray coating paves the way to the widespread application of innovative and versatile hybrid magnetic‐plasmonic nanocomposites.