Abstract

We demonstrate an improved signal-to-noise ratio in a scanning optical microscope used to read out information from a magneto-optical data storage layer. By placing a shading band in the return path of the optical system we can reduce noise by as much as 3 dB in certain spatial frequency ranges. The signal-to-noise ratio improvement arises from differences in the signal and noise distributions in the pupil of the optical system. Although the experimental results are shown only in one dimension, the concept is applicable to two-dimensional scanning of low-contrast samples.

© 1996 Optical Society of America

Full Article  |  PDF Article

References

  • View by:
  • |
  • |
  • |

  1. P. Jacquinot, B. Roizen-Dossier, in Progress in Optics, E. Wolf, ed. (North-Holland, Amsterdam, 1964), Vol. 3, Chap. 2, p. 31.
    [CrossRef]
  2. T. D. Milster, C. H. Curtis, Appl. Opt. 29, 6272 (1992).
    [CrossRef]
  3. H. Ando, T. Yokota, K. Tanoue, Jpn. J. Appl. Phys. 32, 5269 (1993).
    [CrossRef]
  4. E. P. Walker, T. D. Milster, Opt. Lett. 20, 1815 (1995).
    [CrossRef] [PubMed]

1995 (1)

1993 (1)

H. Ando, T. Yokota, K. Tanoue, Jpn. J. Appl. Phys. 32, 5269 (1993).
[CrossRef]

1992 (1)

T. D. Milster, C. H. Curtis, Appl. Opt. 29, 6272 (1992).
[CrossRef]

Ando, H.

H. Ando, T. Yokota, K. Tanoue, Jpn. J. Appl. Phys. 32, 5269 (1993).
[CrossRef]

Curtis, C. H.

T. D. Milster, C. H. Curtis, Appl. Opt. 29, 6272 (1992).
[CrossRef]

Jacquinot, P.

P. Jacquinot, B. Roizen-Dossier, in Progress in Optics, E. Wolf, ed. (North-Holland, Amsterdam, 1964), Vol. 3, Chap. 2, p. 31.
[CrossRef]

Milster, T. D.

E. P. Walker, T. D. Milster, Opt. Lett. 20, 1815 (1995).
[CrossRef] [PubMed]

T. D. Milster, C. H. Curtis, Appl. Opt. 29, 6272 (1992).
[CrossRef]

Roizen-Dossier, B.

P. Jacquinot, B. Roizen-Dossier, in Progress in Optics, E. Wolf, ed. (North-Holland, Amsterdam, 1964), Vol. 3, Chap. 2, p. 31.
[CrossRef]

Tanoue, K.

H. Ando, T. Yokota, K. Tanoue, Jpn. J. Appl. Phys. 32, 5269 (1993).
[CrossRef]

Walker, E. P.

Yokota, T.

H. Ando, T. Yokota, K. Tanoue, Jpn. J. Appl. Phys. 32, 5269 (1993).
[CrossRef]

Appl. Opt. (1)

T. D. Milster, C. H. Curtis, Appl. Opt. 29, 6272 (1992).
[CrossRef]

Jpn. J. Appl. Phys. (1)

H. Ando, T. Yokota, K. Tanoue, Jpn. J. Appl. Phys. 32, 5269 (1993).
[CrossRef]

Opt. Lett. (1)

Other (1)

P. Jacquinot, B. Roizen-Dossier, in Progress in Optics, E. Wolf, ed. (North-Holland, Amsterdam, 1964), Vol. 3, Chap. 2, p. 31.
[CrossRef]

Cited By

OSA participates in CrossRef's Cited-By Linking service. Citing articles from OSA journals and other participating publishers are listed here.

Alert me when this article is cited.


Figures (5)

Fig. 1
Fig. 1

Simple reflection-type scanning optical microscope. Illumination-path filters or return-path filters can be placed in the optical system to change the system transfer function.

Fig. 2
Fig. 2

Influence of the return-path filter on the transfer function. ±1 diffracted orders are produced on reflection from the sample. There is much overlap between the diffracted orders from low-frequency spatial components and the zero order; less overlap is observed at high frequencies. A shading band blocks some of the low-frequency signal, whereas it passes the high-frequency signal.

Fig. 3
Fig. 3

Signal patterns in the pupil after reflection from the sample, showing contour lines of 25%, 50%, and 75%: (a) low-frequency spatial component, (b) spatial frequency ≈N.A./λ = 0.64 μm−1, (c) spatial frequency ≈ 2N.A./λ = 1.28 μm−1, (d) shading band used in the experiments.

Fig. 4
Fig. 4

Noise distributions in the pupil after reflection from the sample, showing contour lines of 25%, 50%, and 75%: (a) total noise with stationary sample, (b) total noise for spatial frequency ≈N.A./λ = 0.64 μm−1, (c) media-noise contribution corresponding to (b).

Fig. 5
Fig. 5

Signal-to-noise ratio as a function of spatial frequency for the system with and without the shading band.

Metrics