Linear birefringence, as implemented in wave plates, is a natural way to control the state of polarization of light. We report on a general method for designing miniature planar wave plates using surface plasmons. The resonant optical device considered here is a single circular aperture surrounded by an elliptical antenna grating. The difference between the short and long axis of each ellipsis ...

The optical principles of indirect ophthalmoscopy were mastered by Gullstrand (I 9 I I) although his ophthalmoscope did not achieve wide popularity because of its complexity and limited field of view. Schepens (I947) demonstrated his binocular indirect ophthalmoscope 2I years ago in the United States of America. The instrument described here is a further stage in simplification (Figs I and 2). ...

Jumping is used in nature by many small animals to locomote in cluttered environments or in rough terrain. It offers small systems the benefit of overcoming relatively large obstacles at a low energetic cost. In order to be able to perform repetitive jumps in a given direction, it is important to be able to upright after landing, steer and jump again. In this article, we review and evaluate the...