Metamaterials are materials with artificial electromagnetic properties defined by their sub-wavelength structure rather than their chemical composition. Negative-index materials (NIMs) are a special class of metamaterials characterized by an effective negative index that gives rise to such unusual wave behaviour as backwards phase propagation and negative refraction. These extraordinary propert...

A new type long period fiber grating is fabricated in all-solid photonic bandgap fiber by periodically drilling microholes using femtosecond laser pulse irradiation. Such a structure introduces a strong refractive index modulation in the waveguide structure and hence exhibits a compact grating dimension. Both the simulation and the experimental results confirm the existence of the light couplin...

Because the refractive index of hemoglobin in the visible range is sensitive to the hemoglobin concentration, optical investigations of hemoglobin are important for medical diagnostics and treatment. Direct measurements of the refractive index are, however, challenging; few such measurements have previously been reported, especially in a wide wavelength range. We directly measured the refractiv...