We systematically examine the conditions of obtaining left-handed ~LH! behavior in photonic crystals. Detailed studies of the phase and group velocities as well as the phase np and group ng refractive indices are given. The existence of negative refraction does not guarantee the existence of negative index of refraction and so LH behavior. A wedge type of experiment is suggested, which can unam...

PURPOSE The purpose of this study was to characterize the central and peripheral refraction across the horizontal meridian of the visual field before and after myopic corneal refractive therapy (CRT) with contact lenses. METHODS Twenty-eight right eyes from 28 subjects (mean age +/- SD = 24.6 +/- 6.3 years) were fitted with Paragon CRT contact lenses to treat myopia between -0.88 and -5.25 D ...

PURPOSE To determine whether the initial characteristics of individual patterns of peripheral refraction relate to subsequent changes in refraction over a one-year period. METHODS 54 myopic and emmetropic subjects (mean age: 24.9±5.1 years; median 24 years) with normal vision were recruited and underwent conventional non-cycloplegic subjective refraction. Peripheral refraction was also measur...

Refraction at a smooth interface is accompanied by momentum transfer normal to the interface. We show that corrugating an initially smooth, totally reflecting, non-metallic interface provides a momentum kick parallel to the surface, which can be used to refract light negatively or positively. This new mechanism of negative refraction is demonstrated by visible light and microwave experiments on...

A method is proposed to create materials with a desired refraction coefficient, possibly negative one. The method consists of embedding into a given material small particles. Given n0(x), the refraction coefficient of the original material in a bounded domain D ⊂ R3, and a desired refraction coefficient n(x), one calculates the number N(x) of small particles, to be embedded in D around a point ...

A three-dimensional extension of the recently demonstrated generalization of the laws of refraction and reflection was investigated for both flat and curved metasurfaces. We found that out-of-plane refraction occurs for a metasurface that imparts a wavevector out of the plane of incidence onto the incident light beam. Metasurfaces provide arbitrary control over the direction of refraction, and ...

We introduce a temporal delay in one beam of the two-color Z-scan apparatus, which measures nondegenerate nonlinear absorption and nondegenerate nonlinear refraction. This technique allows us to time resolve separately the sign and the magnitude of the nonlinear absorption and refraction at frequency p that are due to the presence of a strong excitation at frequency oe. For example, in semicond...

Refraction of black and gray solitons at boundaries separating different defocusing Kerr media is analyzed within a Helmholtz framework. A universal nonlinear Snell’s law is derived that describes gray soliton refraction, in addition to capturing the behavior of bright and black Kerr solitons at interfaces. Key regimes, defined by beam and interface characteristics, are identified and predictio...