Design and fabrication of diffractive optical elements for optical tweezer arrays by means of e-beam lithography

Optical tweezer arrays generated by diffractive optical elements can extend the capabilities to manipulate and organize microscopic particles into complex structures, to sort them intelligently and to study collective behavior in many-body systems materials. We describe new design methods, based on iterative algorithms, to calculate phase-only diffractive optical elements able to generate planar and three-dimensional arrays of tweezers. Experimental results showing the validity of the design approach are presented for an array of eight gaussian spots.