Micro solid immersion lens fabricated by micro-molding for near-field optical data storage

Optical near-field techniques have shown some promise for high-density optical data storage of several tens Gb/in². The diffraction limit of the far-field optics can be greatly relaxed by solid immersion lens (SIL). Recent research on near-field optical recording is focusing on a commercial product: the high-density storage drive. It is attractive to minimize the size and the weight of the SIL to realize a near-field optical pickup head capable of fast tracking and of maintaining a stable gap in the optical near-field regime. A simple and reliable micromachining process is developed to make miniaturized SIL. Polymeric super-hemispherical SIL can be replicated by hot press molding using the micromachined silicon master. The design and fabrication issues of the micromachined silicon master and molding process of the SIL are reported. The magnification factor of the fabricated micro-SIL is 3.143