We analyzed the effects of an external shock on a collision problem in a solid immersion lens (SIL) based near-field
recording (NFR) through a shock response analysis and proposed a possible solution to this problem with adopting a
protector and safety mode. With this proposed method the collision between SIL and media can be avoided. We showed
possible solution for contamination problem in SIL based NFR through a numerical air flow analysis. We also
introduced possible solid immersion lens designs to increase the fabrication and assembly tolerances of an optical head
with replicated lens. Potentially, these research results could advance NFR technology for commercial product.
As a popularity of a portable digital device such as a cellular phone, a digital camera and a MP3 player is spreading, the demand of the mobile storage device increases rapidly. A Blu-ray technology using 406nm laser diode and 0.85 NA(Numerical Aperture) satisfies a miniaturization and a high capacity which are the requirements of the portable device. Because a Blu-ray optical storage device can store 1.5Gbyte on a 3cm disk, it is possible to distribute the media in great quantities and with cheaper price. In this paper, we analyze the optical performance of the hybrid micro lens which is manufactured using a micro fabrication technology. The measurements of the optical power, the spot size and the wavefront error are performed to evaluate the hybrid micro lens with 0.85 NA and the designed wavelength of 406nm. Using the measured data, we estimate if the performance of hybrid micro lens corresponds to the designed performance. Also, the processes of measuring an optical performance of hybrid micro lens, which is composed of the refractive lens and the diffractive lens, are proposed using laser diode of 406nm and finite optics.
We have developed diffractive optical element (DOE) to compensate chromatic aberration happened in aspheric lens surfaces in micro optical system. The DOE was generated with grayscale lithography using high-energy-beam-sensitive (HEBS)-glass, and we finally obtained DOEs having 4levels and 8levels through this fabrication.
In this paper, our aim is to develop a system that can not only maintain stable gap distance under 100nm but also compensate the tilting between a pick-up head and disk surface for near-field recording (NFR), which is known as a key technology for a next generation optical storage. Applying total internal reflection (TIR) to the air gap measurement, we design an optical sensor to measure the gap distances at three points. Stack and bimorph piezoelectric actuators are utilized for high precision control with nanometer resolution. To understand dynamic characteristics of the system, an analytical method for boundary coupled beam model is performed and verified by comparison with the results of the finite element method (FEM).