View rotation with parallel ray-rotating windows

Pairs of planar ray-rotating windows can rotate the view through different angles. The angle by which an object appears rotated is independent of the distance of the object behind the windows. The observer distance has to be chosen such that the observer is in a principal plane of this combination of windows.     

Quantifying metarefraction with confocal lenslet arrays

METATOYs can change the direction of light in ways that appear to, but do not actually, contravene the laws of wave optics. This direction change applies only to part of the transmitted light beam; the remainder gets re-directed differently. For a specific example, namely confocal pairs of rectangular lenslet arrays with no dead area between lenslets, we calculate here the fractions of power of a uniform-intensity light beam incident from a specific (but arbitrary) direction that get re-directed in different ways, and we derive an equation describing this redirection. This will facilitate assessment of the suitability of METATOYs for applications such as solar concentration. Finally, we discuss similarities between the multiple refraction of light at the lenslet arrays and multiple refraction and reflection of cold atoms at a barrier in the presence of the light fields.     

Experimental demonstration of a light-ray-direction-flipping METATOY based on confocal lenticular arrays

We show, theoretically and experimentally, that a sheet formed by two confocal lenticular arrays can flip one component of the local light-ray direction. Ray-optically, such a sheet is equivalent to a Dove-prism sheet, an example of a METATOY (metamaterial for rays), a structure that changes the direction of transmitted light rays in a way that cannot be performed perfectly wave-optically.