Multispectral Photonic Jet Shaping and Steering by Control of Tangential Electric Field Component on Cuboid Particle

In this study, we present the simulations and experimental observations of photonic jet (PJ) shaping by control of tangential electric field components at illuminating wavelengths of 405 nm, 532 nm, and 671 nm. The PJs are generated by a single dielectric 4-micrometer cube that was fabricated from polydimethylsiloxane (PDMS). The dielectric cube is deposited on a silicon substrate and placed on two aluminum masks with a width equal to the side length of the cube. Due to the appearance of the metal masks, the focal length and decay length of the generated PJs decreased almost twice, while the PJ resolution increased 1.2 times. Thus, PJ shaping can be controlled by the presence of the metal mask along the lateral surface of the cube without changing the external shape or internal structure of the cube. This effect is based on the control of the tangential components of the electric field along the lateral surface of the cube. In the case of a one-sided metal mask, the effect of optical deflection and bending is predicted to form a photonic hook. Due to the low cost of these dielectric cubes, they have potential in far-field systems to better meet the requirements of modern optical integration circuits and switches.

Keeping It Unreal: Rap, Racecraft, and MF Doom

Focusing on the masked rapper MF Doom, this article uses Karen E. Fields and Barbara J. Fields’s concept of “racecraft” to theorize how the insidious fiction called “race” shapes and reshapes popular “Black” music. Rap is a mode of racecraft that speculatively binds or “crafts” historical musical forms to “natural,” bio-geographical and -cultural traits. The result is a music that counts as authentic and “real” to the degree that it sounds “Black,” on the one hand, and a “Blackness” that naturally expresses itself in rap, on the other. The case of MF Doom illustrates how racialized peoples can appropriate ascriptive practices to craft their own identities against dominant forms of racecraft. The ideological and political work of “race” is not only oppressive but also gives members of subordinated “races” a means of critique, rebellion, and self-affirmation—an ensemble of counter-science fictions. Doom is a remarkable case study in rap and racecraft because when he puts an anonymous metal mask over the social mask that is his ascribed “race,” he unbinds the latter’s ties while simultaneously revealing racecraft’s durability.

Pantomime horsemen: “cavalry-sports“ helmets and popular culture in the frontier provinces

Decorated helmets fitted with a metal mask in the form of a human face have been found throughout the lands of the Roman empire, and sometimes beyond it. Despite the significant number of examples (whole or in part) surviving from the 1st to the 3rd c. A.D., these helmets remain an enigma to students of the Roman army. They have usually (though not exclusively) been found either at or close to forts garrisoned by cavalry or in hoards or graves containing other military equipment, often cavalry-specific such as horse-chamfrons. Most have therefore been identified as cavalry helmets, and it is widely accepted that many are of the type referred to by the 2nd-c. general Arrian in his treatise Tactica whilst describing cavalry exercises (hippika gymnasia): these helmets, unlike those made for battle, do not protect just the head and cheeks, but are made to fit the faces of the cavalrymen completely, with openings for the eyes so as not to interrupt the vision whilst nevertheless providing protection for the eyes.1