Cover-layer-protected solid immersion lens-based near-field recording with an annular aperture

Yong Joong Yoon, Wan Chin Kim, Kyoung Su Park, No Cheol Park, Young Pil Park

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


Currently, data recording density in cover-layer-protected near-field-recording (NFR) and multiple-recording layered NFR optical data storage technology is limited by the difficulty in obtaining high-refractive-index cover layer materials. In addition, with the exception of improved resolution, the higher the numerical aperture (NA), the poorer the optical characteristics. However, in this study, we present novel cover-layer-protected solid immersion lens (SIL)-based NFR optics that provide superior optical performance with higher recording density, greatly enhanced focal depth, and less sensitivity to near-field air-gap-distance variation by modulating the amplitude and phase in the entrance pupil using annular pupil zones. Using an annular aperture consisting of three concentric annular zones to effect amplitude and phase modulation, the 1.45 NA cover-layer-protected SIL-based NFR optics achieved a data recording density as high as that of conventional 1.80 NA SIL-based NFR optics. These 1.45 NA optics yielded a full-width at half-maximum (FWHM) spot size of 0.315λ, a focal depth of 0.82λ, a focused beam spot sensitivity to air-gap-distance within the near-field region of 0.04λ, and a sidelobe intensity lower than 7%. In comparison with conventional 1.80 NA SIL-based NFR optics, the annular aperture optics achieved 3.5 times longer focal depth and much lower focused beam spot sensitivity to air-gap distance while maintaining the same high resolution. The introduction of this novel specially designed NFR optics could greatly improve data capacity in multiple-recording layered NFR.

Original languageEnglish
Pages (from-to)1883-1889
Number of pages7
JournalJournal of the Optical Society of America A: Optics and Image Science, and Vision
Issue number8
Publication statusPublished - 2009 Aug 1

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Computer Vision and Pattern Recognition


Dive into the research topics of 'Cover-layer-protected solid immersion lens-based near-field recording with an annular aperture'. Together they form a unique fingerprint.

Cite this