Optical trapping with photorefractive electric fields

Trapping with evanescent fields has become an important tool in many research fields. Evanescent fields allow trapping of particles in close proximity to a surface. However, excitation of these waves may be cumbersome. Recently, trapping with photorefractive electric fields has been demonstrated using dielectric and metallic nano and microparticles. Excitation of these fields is straight forward and, in principle, can be excited with microwatt power level. In this work, we give a comparison of photorefractive and plasmonic trapping emphasizing its advantages and disadvantages. We show that single beam and holographic photorefractive photovoltaic trapping in LiNbO3 of microparticle in water is possible.