Author :
Lee, J.H. ; Yoon, H.K. ; Jeong, J.H. ; Oh, H.R. ; Gweon, D.G.
Abstract :
Recently, the NFR (near field recording) system has been introduced as a new optical data storage method to realize higher density recording beyond the diffraction limit (H.K. Yoon et al., KSPE, vol. 17, no. 6, pp. 46-52, 2000; E. Betzig et al., Appl. Phys. Lett., vol. 61, pp. 142-144, 1992; B.D. Terris et al, ibid., vol. 68, no. 2, pp. 141-143, 1996; B.D. Terris et al., ibid., vol. 65, no. 4, pp. 388-390, 1994). It is based on focusing propagating light with an objective lens (OL) onto the bottom of the solid immersion lens (SIL), which is made of a high refractive index (>1.0) to make the numerical aperture (NA) larger than one. However, using the OL and SIL as a focusing unit (FU), there are serious problems, such as alignment error between SIL and OL, and manufacturing errors of the OL and SIL. These errors can cause aberrations and influence the performance of whole recording system. Tight assembling and manufacturing tolerance in NFR is one of the major barriers to be overcome. In this paper, tolerance analysis for the focusing unit of a near field recording system is presented. The assembling and manufacturing tolerances of SIL and OL are simulated. In addition, we proposed to move the collimating lens (CL) back and forth to compensate and control these tolerances, especially in the optical axis direction.
Keywords :
error compensation; lenses; microassembling; optical collimators; optical fabrication; optical focusing; optical storage; refractive index; tolerance analysis; OL/SIL focusing unit; aberration; alignment error; assembling tolerances; collimating lens; diffraction limit; focusing unit; lens manufacturing error; manufacturing tolerances; near field recording system; numerical aperture; objective lens; optical axis direction; optical data storage method; propagating light focusing; recording density; recording system performance; refractive index; solid immersion lens; tolerance analysis; tolerance compensation; tolerance control; Assembly; Lenses; Manufacturing; Memory; Optical diffraction; Optical propagation; Optical recording; Optical refraction; Optical variables control; Tolerance analysis;
