  The limited resolution of a conventional optical microscope stems from the
fact that the subwavelength information of an object is carried by evanescent
waves, which exponentially decays in space and cannot reach the imaging plane.
We introduce here a metamaterial solid immersion lens (mSIL), which utilizes
closely-packed high-index nanoparticles as a composite media to effectively
convert and transport evanescent waves from near-field to far-field. About 20%
of evanescent wave energy of an ideal point source can be directed into
far-field by mSIL. This has led to the exceptional imaging performance of mSIL
in visible. Using 15 nm diameter TiO2 (n=2.55) nanoparticles as building block,
we demonstrated that 45 nm -75 nm features can be resolved by the mSIL under a
white light microscope. Our approach opens up the possibility to obtain a
'perfect lens' using pure dielectric materials.
