Diffractive Optics

Abstract

Diffractive and micro optics have had fast growth in the last 20 years since microlithography technology began to be used for fabrication of optical elements. Nowadays, micro and diffractive optical element ~DOE! fabrication has reached a certain maturity. A wide range of applications has been developed. New applications and new integrated diffractive optical systems continue to emerge. The 22 papers from 16 countries published in this special section on diffractive optics reflect the recent trends and progress in DOE applications, fabrications, optical system design and implementations, and subwavelength structures. Both of us have witnessed and contributed to the progress of diffractive optics technology and have been co-chairing SPIE conferences on diffractive optics at Photonics Asia and the SPIE Annual Meeting, respectively. It is a real pleasure for us to jointly edit the first special section on diffractive optics inOptical Engineering. The recent advances in nanoscale lithography and holography techniques provide a huge potential to create new subwavelength structures that efficiently manipulate light through diffraction and propagation. We believe that the new nanofabrication technologies will once again push diffractive optics and its natural extensions, including subwavelength structures, photonic crystals, near-field optics and surface plasmon polariton optics, etc., to a new fast advance path. The impact will be even more important than what has happened in the last 20 years by the application of microlithography to fabrication of DOEs. In this special section on diffractive optics, new DOE applications include surface plasmon resonance sensors, ultrashort-pulse processing, solar energy systems, interferometric testing, high-power laser beam shaping, dynamic lenses, fiber Bragg grating fabrication, 3-D chipscale optical interconnections, and Talbot array illumination. Pedersen et al. design and imprint near-field surface relief diffractive gratings for beam deflection and focusing in an injection-moulded polymer chip for the new integrated surface plasmon resonance sensor, which is lowcost, compact, and robust with high performance. Lohokare et al. develop a novel conductive polymer-based flip-chip integration process for packaging arrayed VCSELs and microlenses, and demonstrate a 3-D chip-scale optical interconnection system. Grunwald et al. present the spatiotemporal processing of an ultrashort-pulse laser beam by exploiting specific advantages of thin-film micro-optical arrays. Gombert et al. address the design and the whole experimental process for the fabrication of surface-relief microstructures on large areas that are useful in solar energy systems for antireflective surfaces, displays, light trapping in polymer solar cells, and facade protection from sun radiation. Pruss et al. apply computer-generated holograms, which are able to generate several aspheric wave fronts, in interferometer metrology. The system is used for absolute testing of aspheric surfaces and diffractive transmission spheres. For highpower laser beam shaping applications, Liu et al. develop a modified iterative Fourier transform design algorithm. They design the beam shaping DOE and the DOE that combines beam conditioning and fan-out functions for coupling the beam into multimode optical fibers. Ripoll t al. present a review and compare some useful iterative Fourier transform algorithms for the design of continuous and multiphase-level DOEs for beam shaping. In the next three papers, Fresnel near-field diffraction is studied for new applications. Onural discusses mathematical properties of the sampled quadratic phase function ~chirp!, mainly that the Fourier transform of a sampled chirp function is also a sampled chirp function. The results are used in computer simulation of digital Special Section Guest Editorial