Data readout from compact disks by a laser pickup with diffraction optics

Abstract

The production of Na: by laser excitation in the 580-620nm region mainly results from two-photon absorption of the Na, molecules to highly excited gerade state(s) and are subsequently ionised by a third photon. This mechanism, i.e., a two-photon resonance three-photon ionisation process, may account for several recent experimental observations in laser-irradiated sodium vapours. The assignment of the multiphoton ionisation spectrum and the dependence of the yield of Na: on the Na, vapour density and the laser power density are presented.

Rigorous Electromagnetic Analysis of the Focusing Action of Refractive Cylindrical Microlens

“…1,2 Under these circumstances, more and more attention is being paid to microstructure optics elements because various optical elements with submicrometer-sized structure, for instance, diffractive microlens, refractive microlens, and microlens arrays, are of importance in the integrated micro-opto-electro-mechanical systems (MOEMs). However, because of their small feature sizes, the light scattering effect in the elements is more important than the light diffraction effect, and the scalar diffraction theory conventionally used fails completely.…”