Abstract

Results of vector diffraction simulations pertaining to the effective groove depth for various disks with different groove parameters, different coatings, and different incident polarizations are presented. The effective depth deviates from the physical depth if the track pitch approaches the wavelength of the light source. Moreover, the difference of the effective depth for the two polarization states is demonstrated. The effective depth is usually shallower than the physical depth, especially for deeper grooves. The ray-bending mechanism associated with the objective lens and the different response to s- and p-polarized light on reflection from the disk surface impact the effective depth for objective lenses with different numerical apertures.

© 2000 Optical Society of America

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  1. K. Kayanuma, T. Iwanaga, H. Inada, K. Okanoue, R. Katayam, K. Yoshihara, Y. Yamanaka, M. Tsunekane, O. Okada, “High track density magneto-optical recording using a cross-talk canceler,” in Optical Data Storage, Y. Tsunoda, M. de Haan, eds., Proc. SPIE1316, 35–39 (1990).
    [CrossRef]
  2. N. Miyagawa, Y. Gotoh, E. Ohno, K. Nishiuchi, N. Akahira, “Land and groove recording for high track density on phase-change optical disks,” Jpn. J. Appl. Phys. 32, 5324–5328 (1993).
    [CrossRef]
  3. K. Nishimura, T. Suzuki, K. Takeguchi, I. Morimoto, “High density land and groove recording on phase change optical disk,” Proceedings of Symposium on Optical Memory 1994 (Japan Society of Applied Physics, Tokyo, 1994), pp. 37–38.
  4. K. Narita, T. Kawano, H. Takeshima, “Feasibility study of high density land/groove recording on magnetooptical disks,” Jpn. J. Appl. Phys. 36, 495–499 (1997).
    [CrossRef]
  5. T. D. Goodman, M. Mansuripur, “Optimization of groove depth for cross-talk cancellation in the scheme of land–groove recording in magneto-optic disk systems,” Appl. Opt. 35, 1107–1119 (1996).
    [CrossRef] [PubMed]
  6. S. Morita, M. Nishiyama, T. Ueda, “Super-high-density optical disk using deep groove method,” Jpn. J. Appl. Phys. 36, 444–449 (1997).
    [CrossRef]
  7. P. Sheng, “Theoretical considerations of optical diffraction from RCA VideoDisc signals,” RCA Rev. 39, 512–555 (1978).
  8. K. Ohta, Y. Murakami, T. Inui, A. Takahashi, T. Deguchi, S. Katoh, “Relation between groove shape and signal quality in magneto-optical disks,” IEEE Trans. Magn. Jpn. 8, 710–719 (1987).
    [CrossRef]
  9. R. E. Gerber, M. Mansuripur, “Dependence of the tracking performance of an optical disk on the direction of the incident-light polarization,” Appl. Opt. 34, 8192–8200 (1995).
    [CrossRef] [PubMed]
  10. K. B. Chung, “Numerical analysis of readout-signal cross talk in magneto-optical land and groove recording,” Appl. Opt. 36, 1789–1795 (1997).
    [CrossRef] [PubMed]
  11. H. H. Hopkins, “Diffraction theory of laser read-out systems for optical video discs,” J. Opt. Soc. Am. 69, 4–24 (1979).
    [CrossRef]
  12. J. Pasman, “Vector theory of diffraction,” in Principles of Optical Disc Systems, G. Bouwhuis, J. Braat, A. Huijser, J. Pasman, G. van Rosmalen, K. Schouhamer Immink, eds. (Hilger, Bristol, UK, 1985), pp. 88–124.
  13. M. Ogawa, M. Nakada, R. Katayama, M. Okada, M. Itoh, “Analysis of scattering light from magnetic material with land/groove by three-dimensional boundary element method,” Jpn. J. Appl. Phys. 35, 336–341 (1996).
    [CrossRef]
  14. W. A. Challener, “Vector diffraction of a grating with conformal thin films,” J. Opt. Soc. Am. A 13, 1859–1869 (1996).
    [CrossRef]
  15. W. C. Liu, M. W. Kowarz, “Vector diffraction from subwavelength optical disk structures: two-dimensional near-field profiles,” Opt. Exp. 2, 191–197 (1998).
    [CrossRef]
  16. The computer program delta is commercially available from Lifeng Li. The theoretical basis of this program is described in the following paper: L. Li, “Multilayer-coated diffraction gratings: differential method of Chandezon et al. revisited,” J. Opt. Soc. Am. A 11, 2816–2828 (1994).
    [CrossRef]
  17. diffract is a product of MM Research, Inc., Tucson, Ariz.Its theoretical basis has been described in the following papers by M. Mansuripur: “Certain computational aspects of vector diffraction problems,” J. Opt. Soc. Am. A 6, 786–805 (1989); “Distribution of light at and near the focus of high-numerical-aperture objectives,” J. Opt. Soc. Am. A 3, 2086–2093 (1986); erratum, 382–383 (1993); “Analysis of multilayer thin film structures containing magneto-optic and anisotropic media at oblique incidence using 2 × 2 matrices,” J. Appl. Phys. 67, 6466–6475 (1990).

1998

W. C. Liu, M. W. Kowarz, “Vector diffraction from subwavelength optical disk structures: two-dimensional near-field profiles,” Opt. Exp. 2, 191–197 (1998).
[CrossRef]

1997

K. Narita, T. Kawano, H. Takeshima, “Feasibility study of high density land/groove recording on magnetooptical disks,” Jpn. J. Appl. Phys. 36, 495–499 (1997).
[CrossRef]

S. Morita, M. Nishiyama, T. Ueda, “Super-high-density optical disk using deep groove method,” Jpn. J. Appl. Phys. 36, 444–449 (1997).
[CrossRef]

K. B. Chung, “Numerical analysis of readout-signal cross talk in magneto-optical land and groove recording,” Appl. Opt. 36, 1789–1795 (1997).
[CrossRef] [PubMed]

1996

1995

1994

1993

N. Miyagawa, Y. Gotoh, E. Ohno, K. Nishiuchi, N. Akahira, “Land and groove recording for high track density on phase-change optical disks,” Jpn. J. Appl. Phys. 32, 5324–5328 (1993).
[CrossRef]

1987

K. Ohta, Y. Murakami, T. Inui, A. Takahashi, T. Deguchi, S. Katoh, “Relation between groove shape and signal quality in magneto-optical disks,” IEEE Trans. Magn. Jpn. 8, 710–719 (1987).
[CrossRef]

1979

1978

P. Sheng, “Theoretical considerations of optical diffraction from RCA VideoDisc signals,” RCA Rev. 39, 512–555 (1978).

Akahira, N.

N. Miyagawa, Y. Gotoh, E. Ohno, K. Nishiuchi, N. Akahira, “Land and groove recording for high track density on phase-change optical disks,” Jpn. J. Appl. Phys. 32, 5324–5328 (1993).
[CrossRef]

Challener, W. A.

Chung, K. B.

Deguchi, T.

K. Ohta, Y. Murakami, T. Inui, A. Takahashi, T. Deguchi, S. Katoh, “Relation between groove shape and signal quality in magneto-optical disks,” IEEE Trans. Magn. Jpn. 8, 710–719 (1987).
[CrossRef]

Gerber, R. E.

Goodman, T. D.

Gotoh, Y.

N. Miyagawa, Y. Gotoh, E. Ohno, K. Nishiuchi, N. Akahira, “Land and groove recording for high track density on phase-change optical disks,” Jpn. J. Appl. Phys. 32, 5324–5328 (1993).
[CrossRef]

Hopkins, H. H.

Inada, H.

K. Kayanuma, T. Iwanaga, H. Inada, K. Okanoue, R. Katayam, K. Yoshihara, Y. Yamanaka, M. Tsunekane, O. Okada, “High track density magneto-optical recording using a cross-talk canceler,” in Optical Data Storage, Y. Tsunoda, M. de Haan, eds., Proc. SPIE1316, 35–39 (1990).
[CrossRef]

Inui, T.

K. Ohta, Y. Murakami, T. Inui, A. Takahashi, T. Deguchi, S. Katoh, “Relation between groove shape and signal quality in magneto-optical disks,” IEEE Trans. Magn. Jpn. 8, 710–719 (1987).
[CrossRef]

Itoh, M.

M. Ogawa, M. Nakada, R. Katayama, M. Okada, M. Itoh, “Analysis of scattering light from magnetic material with land/groove by three-dimensional boundary element method,” Jpn. J. Appl. Phys. 35, 336–341 (1996).
[CrossRef]

Iwanaga, T.

K. Kayanuma, T. Iwanaga, H. Inada, K. Okanoue, R. Katayam, K. Yoshihara, Y. Yamanaka, M. Tsunekane, O. Okada, “High track density magneto-optical recording using a cross-talk canceler,” in Optical Data Storage, Y. Tsunoda, M. de Haan, eds., Proc. SPIE1316, 35–39 (1990).
[CrossRef]

Katayam, R.

K. Kayanuma, T. Iwanaga, H. Inada, K. Okanoue, R. Katayam, K. Yoshihara, Y. Yamanaka, M. Tsunekane, O. Okada, “High track density magneto-optical recording using a cross-talk canceler,” in Optical Data Storage, Y. Tsunoda, M. de Haan, eds., Proc. SPIE1316, 35–39 (1990).
[CrossRef]

Katayama, R.

M. Ogawa, M. Nakada, R. Katayama, M. Okada, M. Itoh, “Analysis of scattering light from magnetic material with land/groove by three-dimensional boundary element method,” Jpn. J. Appl. Phys. 35, 336–341 (1996).
[CrossRef]

Katoh, S.

K. Ohta, Y. Murakami, T. Inui, A. Takahashi, T. Deguchi, S. Katoh, “Relation between groove shape and signal quality in magneto-optical disks,” IEEE Trans. Magn. Jpn. 8, 710–719 (1987).
[CrossRef]

Kawano, T.

K. Narita, T. Kawano, H. Takeshima, “Feasibility study of high density land/groove recording on magnetooptical disks,” Jpn. J. Appl. Phys. 36, 495–499 (1997).
[CrossRef]

Kayanuma, K.

K. Kayanuma, T. Iwanaga, H. Inada, K. Okanoue, R. Katayam, K. Yoshihara, Y. Yamanaka, M. Tsunekane, O. Okada, “High track density magneto-optical recording using a cross-talk canceler,” in Optical Data Storage, Y. Tsunoda, M. de Haan, eds., Proc. SPIE1316, 35–39 (1990).
[CrossRef]

Kowarz, M. W.

W. C. Liu, M. W. Kowarz, “Vector diffraction from subwavelength optical disk structures: two-dimensional near-field profiles,” Opt. Exp. 2, 191–197 (1998).
[CrossRef]

Li, L.

Liu, W. C.

W. C. Liu, M. W. Kowarz, “Vector diffraction from subwavelength optical disk structures: two-dimensional near-field profiles,” Opt. Exp. 2, 191–197 (1998).
[CrossRef]

Mansuripur, M.

Miyagawa, N.

N. Miyagawa, Y. Gotoh, E. Ohno, K. Nishiuchi, N. Akahira, “Land and groove recording for high track density on phase-change optical disks,” Jpn. J. Appl. Phys. 32, 5324–5328 (1993).
[CrossRef]

Morimoto, I.

K. Nishimura, T. Suzuki, K. Takeguchi, I. Morimoto, “High density land and groove recording on phase change optical disk,” Proceedings of Symposium on Optical Memory 1994 (Japan Society of Applied Physics, Tokyo, 1994), pp. 37–38.

Morita, S.

S. Morita, M. Nishiyama, T. Ueda, “Super-high-density optical disk using deep groove method,” Jpn. J. Appl. Phys. 36, 444–449 (1997).
[CrossRef]

Murakami, Y.

K. Ohta, Y. Murakami, T. Inui, A. Takahashi, T. Deguchi, S. Katoh, “Relation between groove shape and signal quality in magneto-optical disks,” IEEE Trans. Magn. Jpn. 8, 710–719 (1987).
[CrossRef]

Nakada, M.

M. Ogawa, M. Nakada, R. Katayama, M. Okada, M. Itoh, “Analysis of scattering light from magnetic material with land/groove by three-dimensional boundary element method,” Jpn. J. Appl. Phys. 35, 336–341 (1996).
[CrossRef]

Narita, K.

K. Narita, T. Kawano, H. Takeshima, “Feasibility study of high density land/groove recording on magnetooptical disks,” Jpn. J. Appl. Phys. 36, 495–499 (1997).
[CrossRef]

Nishimura, K.

K. Nishimura, T. Suzuki, K. Takeguchi, I. Morimoto, “High density land and groove recording on phase change optical disk,” Proceedings of Symposium on Optical Memory 1994 (Japan Society of Applied Physics, Tokyo, 1994), pp. 37–38.

Nishiuchi, K.

N. Miyagawa, Y. Gotoh, E. Ohno, K. Nishiuchi, N. Akahira, “Land and groove recording for high track density on phase-change optical disks,” Jpn. J. Appl. Phys. 32, 5324–5328 (1993).
[CrossRef]

Nishiyama, M.

S. Morita, M. Nishiyama, T. Ueda, “Super-high-density optical disk using deep groove method,” Jpn. J. Appl. Phys. 36, 444–449 (1997).
[CrossRef]

Ogawa, M.

M. Ogawa, M. Nakada, R. Katayama, M. Okada, M. Itoh, “Analysis of scattering light from magnetic material with land/groove by three-dimensional boundary element method,” Jpn. J. Appl. Phys. 35, 336–341 (1996).
[CrossRef]

Ohno, E.

N. Miyagawa, Y. Gotoh, E. Ohno, K. Nishiuchi, N. Akahira, “Land and groove recording for high track density on phase-change optical disks,” Jpn. J. Appl. Phys. 32, 5324–5328 (1993).
[CrossRef]

Ohta, K.

K. Ohta, Y. Murakami, T. Inui, A. Takahashi, T. Deguchi, S. Katoh, “Relation between groove shape and signal quality in magneto-optical disks,” IEEE Trans. Magn. Jpn. 8, 710–719 (1987).
[CrossRef]

Okada, M.

M. Ogawa, M. Nakada, R. Katayama, M. Okada, M. Itoh, “Analysis of scattering light from magnetic material with land/groove by three-dimensional boundary element method,” Jpn. J. Appl. Phys. 35, 336–341 (1996).
[CrossRef]

Okada, O.

K. Kayanuma, T. Iwanaga, H. Inada, K. Okanoue, R. Katayam, K. Yoshihara, Y. Yamanaka, M. Tsunekane, O. Okada, “High track density magneto-optical recording using a cross-talk canceler,” in Optical Data Storage, Y. Tsunoda, M. de Haan, eds., Proc. SPIE1316, 35–39 (1990).
[CrossRef]

Okanoue, K.

K. Kayanuma, T. Iwanaga, H. Inada, K. Okanoue, R. Katayam, K. Yoshihara, Y. Yamanaka, M. Tsunekane, O. Okada, “High track density magneto-optical recording using a cross-talk canceler,” in Optical Data Storage, Y. Tsunoda, M. de Haan, eds., Proc. SPIE1316, 35–39 (1990).
[CrossRef]

Pasman, J.

J. Pasman, “Vector theory of diffraction,” in Principles of Optical Disc Systems, G. Bouwhuis, J. Braat, A. Huijser, J. Pasman, G. van Rosmalen, K. Schouhamer Immink, eds. (Hilger, Bristol, UK, 1985), pp. 88–124.

Sheng, P.

P. Sheng, “Theoretical considerations of optical diffraction from RCA VideoDisc signals,” RCA Rev. 39, 512–555 (1978).

Suzuki, T.

K. Nishimura, T. Suzuki, K. Takeguchi, I. Morimoto, “High density land and groove recording on phase change optical disk,” Proceedings of Symposium on Optical Memory 1994 (Japan Society of Applied Physics, Tokyo, 1994), pp. 37–38.

Takahashi, A.

K. Ohta, Y. Murakami, T. Inui, A. Takahashi, T. Deguchi, S. Katoh, “Relation between groove shape and signal quality in magneto-optical disks,” IEEE Trans. Magn. Jpn. 8, 710–719 (1987).
[CrossRef]

Takeguchi, K.

K. Nishimura, T. Suzuki, K. Takeguchi, I. Morimoto, “High density land and groove recording on phase change optical disk,” Proceedings of Symposium on Optical Memory 1994 (Japan Society of Applied Physics, Tokyo, 1994), pp. 37–38.

Takeshima, H.

K. Narita, T. Kawano, H. Takeshima, “Feasibility study of high density land/groove recording on magnetooptical disks,” Jpn. J. Appl. Phys. 36, 495–499 (1997).
[CrossRef]

Tsunekane, M.

K. Kayanuma, T. Iwanaga, H. Inada, K. Okanoue, R. Katayam, K. Yoshihara, Y. Yamanaka, M. Tsunekane, O. Okada, “High track density magneto-optical recording using a cross-talk canceler,” in Optical Data Storage, Y. Tsunoda, M. de Haan, eds., Proc. SPIE1316, 35–39 (1990).
[CrossRef]

Ueda, T.

S. Morita, M. Nishiyama, T. Ueda, “Super-high-density optical disk using deep groove method,” Jpn. J. Appl. Phys. 36, 444–449 (1997).
[CrossRef]

Yamanaka, Y.

K. Kayanuma, T. Iwanaga, H. Inada, K. Okanoue, R. Katayam, K. Yoshihara, Y. Yamanaka, M. Tsunekane, O. Okada, “High track density magneto-optical recording using a cross-talk canceler,” in Optical Data Storage, Y. Tsunoda, M. de Haan, eds., Proc. SPIE1316, 35–39 (1990).
[CrossRef]

Yoshihara, K.

K. Kayanuma, T. Iwanaga, H. Inada, K. Okanoue, R. Katayam, K. Yoshihara, Y. Yamanaka, M. Tsunekane, O. Okada, “High track density magneto-optical recording using a cross-talk canceler,” in Optical Data Storage, Y. Tsunoda, M. de Haan, eds., Proc. SPIE1316, 35–39 (1990).
[CrossRef]

Appl. Opt.

IEEE Trans. Magn. Jpn.

K. Ohta, Y. Murakami, T. Inui, A. Takahashi, T. Deguchi, S. Katoh, “Relation between groove shape and signal quality in magneto-optical disks,” IEEE Trans. Magn. Jpn. 8, 710–719 (1987).
[CrossRef]

J. Opt. Soc. Am.

J. Opt. Soc. Am. A

Jpn. J. Appl. Phys.

M. Ogawa, M. Nakada, R. Katayama, M. Okada, M. Itoh, “Analysis of scattering light from magnetic material with land/groove by three-dimensional boundary element method,” Jpn. J. Appl. Phys. 35, 336–341 (1996).
[CrossRef]

N. Miyagawa, Y. Gotoh, E. Ohno, K. Nishiuchi, N. Akahira, “Land and groove recording for high track density on phase-change optical disks,” Jpn. J. Appl. Phys. 32, 5324–5328 (1993).
[CrossRef]

K. Narita, T. Kawano, H. Takeshima, “Feasibility study of high density land/groove recording on magnetooptical disks,” Jpn. J. Appl. Phys. 36, 495–499 (1997).
[CrossRef]

S. Morita, M. Nishiyama, T. Ueda, “Super-high-density optical disk using deep groove method,” Jpn. J. Appl. Phys. 36, 444–449 (1997).
[CrossRef]

Opt. Exp.

W. C. Liu, M. W. Kowarz, “Vector diffraction from subwavelength optical disk structures: two-dimensional near-field profiles,” Opt. Exp. 2, 191–197 (1998).
[CrossRef]

RCA Rev.

P. Sheng, “Theoretical considerations of optical diffraction from RCA VideoDisc signals,” RCA Rev. 39, 512–555 (1978).

Other

K. Nishimura, T. Suzuki, K. Takeguchi, I. Morimoto, “High density land and groove recording on phase change optical disk,” Proceedings of Symposium on Optical Memory 1994 (Japan Society of Applied Physics, Tokyo, 1994), pp. 37–38.

diffract is a product of MM Research, Inc., Tucson, Ariz.Its theoretical basis has been described in the following papers by M. Mansuripur: “Certain computational aspects of vector diffraction problems,” J. Opt. Soc. Am. A 6, 786–805 (1989); “Distribution of light at and near the focus of high-numerical-aperture objectives,” J. Opt. Soc. Am. A 3, 2086–2093 (1986); erratum, 382–383 (1993); “Analysis of multilayer thin film structures containing magneto-optic and anisotropic media at oblique incidence using 2 × 2 matrices,” J. Appl. Phys. 67, 6466–6475 (1990).

J. Pasman, “Vector theory of diffraction,” in Principles of Optical Disc Systems, G. Bouwhuis, J. Braat, A. Huijser, J. Pasman, G. van Rosmalen, K. Schouhamer Immink, eds. (Hilger, Bristol, UK, 1985), pp. 88–124.

K. Kayanuma, T. Iwanaga, H. Inada, K. Okanoue, R. Katayam, K. Yoshihara, Y. Yamanaka, M. Tsunekane, O. Okada, “High track density magneto-optical recording using a cross-talk canceler,” in Optical Data Storage, Y. Tsunoda, M. de Haan, eds., Proc. SPIE1316, 35–39 (1990).
[CrossRef]

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Figures (14)

Fig. 1
Fig. 1

Diagram of the simulated optical system. The incident beam (λ0 = 0.65 µm) is brought to focus by an aberration-free objective lens. Determined by the polarizer, two polarization states [one is parallel (X) and the other is perpendicular (Y) to the grooves] are chosen in the simulations. The groove has a trapezoidal shape with a period of p, a groove width of g, a duty cycle of (g/p), an inclination angle of α, and a physical depth of t.

Fig. 2
Fig. 2

Quadrilayer structure of (a) an air-incident MO disk and (b) a substrate-incident MO disk used in this study. The typical values of the diagonal and the off-diagonal elements of the dielectric tensor of the magnetic layer at λ0 = 0.65 µm are ∊ = -8 + 28.7i and ∊′ = 0.67 - 0.16i.

Fig. 3
Fig. 3

Computed phase distribution of the focused spot, the Airy pattern, when a uniform incident beam is brought to focus by a 0.5-NA objective lens. The gray scale encodes angles from 0° (gray) to +180° (white).

Fig. 4
Fig. 4

(a) Computed phase distribution for a 0.1-NA objective lens and a bare glass (or plastic) disk with p = 2 µm, t = 0.167λ0, and α = 75°. (b) The cross section (along the Y direction) of the phase distribution shows Δϕ = 123°, which corresponds to t eff = 0.171λ0. The obtained phase pattern and the phase difference are the same for X- and Y-polarized light.

Fig. 5
Fig. 5

Computed phase patterns for a bare disk with p = 0.65 µm, t = 0.167λ0, and α = 75°. The incident beam is with X- (top row) and Y- (bottom row) polarized light. (a) and (b) are for a 0.5-NA objective lens. The effective depth at the central bright spot (Airy disk) is 0.138λ0 for (a) and 0.129λ0 for (b). (c) and (d) are for a 0.25-NA objective lens. The effective depth at the central bright spot is 0.139λ0 for (c) and 0.101λ0 for (d).

Fig. 6
Fig. 6

Computed phase patterns for an aluminum-coated disk with p = 0.65 µm, t = 0.167λ0, and α = 75°. The incident beam is with X- (top row) and Y- (bottom row) polarized light. (a) and (b) are for a 0.5-NA objective lens. The effective depth at the central bright spot (Airy disk) is 0.093λ0 for (a) and 0.147λ0 for (b). (c) and (d) are for a 0.25-NA objective lens. The effective depth at the central bright spot is 0.082λ0 for (c) and 0.204λ0 for (d).

Fig. 7
Fig. 7

Computed phase patterns for the MO disk (air-incident medium) with p = 0.65 µm, t = 0.167λ0, and α = 75°. The incident beam is with X- (top row) and Y- (bottom row) polarized light. (a) and (b) are for a 0.5-NA objective lens. The effective depth at the central bright spot (Airy disk) is 0.128λ0 for (a) and 0.129λ0 for (b). (c) and (d) are for a 0.25-NA objective lens. The effective depth at the central bright spot is 0.114λ0 for (c) and 0.118λ0 for (d).

Fig. 8
Fig. 8

Computed phase patterns for a bare disk with p = 0.52 µm, t = 0.167λ0, and α = 75°. The incident beam is with X- (top row) and Y- (bottom row) polarized light. (a) and (b) are for a 0.8-NA objective lens. (c) and (d) are for a 0.5-NA objective lens. (e) and (f) are for a 0.25-NA objective lens. Because of the small grating period (p < λ), the light from the small-NA lens is not modulated by the grating profile.

Fig. 9
Fig. 9

Computed effective depth versus track pitch (p) for a 0.5-NA objective lens and for both bare glass and aluminum-coated disks with t = 0.167λ0 and α = 75°. The result is plotted on a logarithmic scale for the track pitch.

Fig. 10
Fig. 10

Computed effective depth versus inclination angle (α) for a 0.5-NA objective lens and for both bare and aluminum-coated disks with p = 0.65 µm and t = 0.167λ0.

Fig. 11
Fig. 11

Computed effective depth versus physical depth (t) for a 0.5-NA objective lens and for both bare and aluminum-coated disks with p = 0.65 µm and α = 75°.

Fig. 12
Fig. 12

Computed effective depth versus NA of the objective lens for both bare and aluminum-coated disks with p = 0.65 µm, α = 75°, and t = 0.167λ0.

Fig. 13
Fig. 13

Computed effective depth versus NA of the objective lens for the air-incident MO disk [see Fig. 2(a)] with α = 75° and t = 0.167λ0. Three different track pitches, p = 0.65, 1.0, and 1.2 µm, are simulated.

Fig. 14
Fig. 14

Computed effective depth versus NA of the objective lens for the substrate-incident disks. These disks, including a bare disk, an aluminum-coated disk, and an MO disk [see Fig. 2(b)], are assumed to have p = 0.65 µm, α = 75°, and nt = 0.167λ0, where n = 1.5 is the refractive index of the substrate.

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