Real time modulable multifocality through annular optical elements

摘要

We present and analyze new multifocal optical elements based onan annular distribution of the transmittance. These elements provideselectable number of foci and can be designed to work between two fixedpositions or even to provide extended focal depth. The energy of the focican be modulated through a single parameter that controls the area of eachring. In our study we analyze the quality of the peaks and also the limitnumber of foci that can be obtained. The properties shown by theseelements make them usable in instrumental optics or in ophthalmic optics,as new intraocular implants, where multifocal elements are required. Theimplementation has been done on a twisted nematic spatial light modulator,thus allowing real time reconfiguration of the element.