Abstract: Structured screens for the controlled spreading, diffusion, or scattering of an incident beam are provided. The screens are composed of microstructures (1,2) whose configurations and distribution on the surfaces of the screen are precisely determined. In certain embodiments, the configurations and/or their distribution is randomized. The structured screens can be used as diffusing screens or display screens.

Abstract: A lens shapes a diverging laser diode beam, and particularly circularizes and collimates, or diverges, or converges the beam. The lens may be part of an optical system, or part of a laser diode assembly. The lens is constituted of a body, the opposite ends of which are spaced from each other. The surfaces of the ends may be toric with the toric centers being coincident with the optical axis. The surfaces also have curvature profiles which circularize and collimates, or diverges, or converges collimates the beam. The curvature profile of one of the first and second surfaces has a correction profile which is a function of Zernike polynomials, thereby reducing wavefront error of the beam exiting the lens. The correction profile is also a function of the offset of the laser diode from the optical axis (misalignment), thereby increasing the misalignment tolerances for beam to lens centering. The curvature profiles of the surfaces may have correction for astigmatism in the beam shape produced by the laser diode.

Abstract: A polychromatic diffractive lens is usable with broadband or multi-spectral illumination to bring a plurality of spectral components of the illumination to a common focus in space. The lens has a Fresnel zone structure of zones and a profile which provides a phase jump delay at each zone boundary to the illumination of at least one of the spectral components which is greater than one period (wave) of that wavelength, and more particularly, a multiple of 2.pi.p, where p is an integer greater than or equal to two. The parameter p and the width of the zones are selected so that the spectral components are directed, and if desired directed so as to be brought to the common focus with high diffraction efficiency in distinct diffractive orders, the lens thereby being a multi-order diffractive (MOD) lens.