Near-field Solid Immersion Lens Research Articles

Optimizing the optical field distribution of near-field SIL optical storage system using five-zone binary phase filters

Five-zone binary phase filters (FBPFs) are proposed for decreasing the spot size and/or increasing the focal depth of the near-field optical storage system with a hemisphere solid immersion lens (SIL). The design of filters is based on the vector diffraction theory and the MATLAB optimizing toolbox. Three FBPFs with rotationally symmetrical pupil function have been designed, where the one FBPF is for increasing the focal depth as big as possible, the second FBPF is for improving the resolution as high as possible, and the third FBPF integrate the increase of focal depth with the improvement of resolution. Numerical results show that compared with the three-zone amplitude filter, the designed five-zone binary phase-only filters have more prominent performances in improving the focal depth and the resolution of the near-field SIL optical storage system.

Simulation of Contaminates Around the Solid Immersion Lens in a Near-Field Optical Recording System

Accurate predictions of contamination in next-generation optical storage drives are paramount when active gap control is employed. In near-field recording devices, the read/write interface can be on the order of 20-30 nm, which means that the gap could be quite susceptible to contamination. Predictive modeling approaches for studying the behavior of contaminates in nanoscale hydrodynamic interfaces are needed. Here, we present such a model. The interface consists of a flat disk surface translating under a solid immersion lens (SIL) of hemispherical geometry. We present the computational modeling simulation results for nano-scale contaminates around the near-field SIL. The simulation shows that the discrete contaminates actually circumnavigate the SIL/disk interface during operation. We identify and discuss the external influences on the discrete contaminate particle behavior

Near-field solid immersion lens microscope with advanced compact mechanical design

A compact mechanical package is developed for a standard microscope that implements a solid immersion lens (SIL) on a retractable bimorph swing arm. With the compact package mounted on an inverted microscope, far-field and near-field images are obtained at the same location by moving the SIL with the swing arm. With white-light incoherent illumination, the resolution of this system for observing digital versatile discs is around 200 nm with an effective numerical aperture of 1.5. Imaging with the SIL is compared with an atomic force microscopy scan.

Theoretical study of near-field optical storage with a solid immersion lens

Both the reflection inside a hemisphere solid immersion lens (SIL) and the reflection inside the gap between the SIL and the optical recording medium are considered. The near-field SIL imaging theory for high numerical aperture is developed by using the vector diffraction and thin-film optics. Numerical results show that the spot size, Strehl ratio, and sidelobe intensity have an oscillatory behavior with the change of thickness of the air gap, which results from the interference effect of the transmitted field. We find that for smaller spot size, the Strehl ratio is smaller but the sidelobe intensity is larger. A certain thickness of air gap is useful for optical storage, which is less than 63 nm for the system in the simulated examples.

A new three-zone amplitude-only filter for increasing the focal depth of near-field solid immersion lens systems

The near-field solid immersion lens (SIL) system with high numerical aperture exhibits high-quality resolution but its focal depth is at the nanoscale. This drawback limits its applications in high-density optical storage and photolithography. A new three-zone amplitude-only filter is proposed, to increase the focal depth and further improve the resolution of SIL systems. The procedure for designing a rotationally symmetric pupil-plane filter is presented, to control the three-dimensional intensity distribution of a SIL system near focus. The spot size, focal depth, Strehl ratio, and sidelobe intensity are analysed in detail. Numerical simulations show that, using the proposed filter, focal depth and resolution can be increased and sidelobe intensity can be suppressed.

Optical Microstructure of CuPc Thin Film Prepared by Thermal Evaporation

The α-type CuPc thin film prepared by thermal evaporation has the b-axes parallel to the substrate plane. We report the comparison of the optical structure and the height image of CuPc layer deposited on Si surface using the Near-field solid immersion lens (NSIL) and a contact AFM. The optical microstructure of CuPc surface was measured by focusing a laser beam(λ=442 nm) in a solid immersion lens(SIL).