Abstract

We describe a two-color light-emitting-diode source that provides intense, uniform, and highly stable illumination with a wavelength precision sufficient for multiwavelength phase-shifting interferometry applications. The source has feedback-stabilized intensity and junction temperature sensing for wavelength compensation. It has a theoretical mean time between failure of more than 30,000 h, and the two colors provide a step measurement capability of greater than 2.5 μm. Measurements made with this source in an interferometric microscope show subangstrom repeatability.

© 1993 Optical Society of America

Full Article  |  PDF Article

References

  • View by:
  • |
  • |
  • |

  1. T. Fujihara, Y. Shimada, C. Nagano, K. Tsukamoto, “Illuminating device for microscopes,”U.S. patent4,852,985 (August1, 1989).
  2. J. C. Wyant, C. L. Koliopoulis, B. Bushan, D. Basila, J. Tribol. 108, 1 (1986).
    [CrossRef]
  3. J. F. Biegen, R. A. Smythe, Surf. Topography 1, 469 (1988).
  4. T. A. Nussmeier, “Interferometric distance measurement method,”U.S. patent4,355, 899 (October26, 1982).
  5. Y. Y. Cheng, J. C. Wyant, Appl. Opt. 23, 4539 (1984).
    [CrossRef] [PubMed]
  6. K. Creath, Appl. Opt. 26, 2810 (1987).
    [CrossRef] [PubMed]
  7. P. J. de Groot, S. Kishner, Appl. Opt. 30, 4026 (1991).
    [CrossRef] [PubMed]
  8. C. P. Brophy, J. Opt. Soc. Am. A 7, 537 (1990).
    [CrossRef]
  9. J. van Wingerden, H. J. Frankena, C. Smorenburg, Appl. Opt. 30, 2718 (1991).
    [CrossRef] [PubMed]

1991

1990

1988

J. F. Biegen, R. A. Smythe, Surf. Topography 1, 469 (1988).

1987

1986

J. C. Wyant, C. L. Koliopoulis, B. Bushan, D. Basila, J. Tribol. 108, 1 (1986).
[CrossRef]

1984

Basila, D.

J. C. Wyant, C. L. Koliopoulis, B. Bushan, D. Basila, J. Tribol. 108, 1 (1986).
[CrossRef]

Biegen, J. F.

J. F. Biegen, R. A. Smythe, Surf. Topography 1, 469 (1988).

Brophy, C. P.

Bushan, B.

J. C. Wyant, C. L. Koliopoulis, B. Bushan, D. Basila, J. Tribol. 108, 1 (1986).
[CrossRef]

Cheng, Y. Y.

Creath, K.

de Groot, P. J.

Frankena, H. J.

Fujihara, T.

T. Fujihara, Y. Shimada, C. Nagano, K. Tsukamoto, “Illuminating device for microscopes,”U.S. patent4,852,985 (August1, 1989).

Kishner, S.

Koliopoulis, C. L.

J. C. Wyant, C. L. Koliopoulis, B. Bushan, D. Basila, J. Tribol. 108, 1 (1986).
[CrossRef]

Nagano, C.

T. Fujihara, Y. Shimada, C. Nagano, K. Tsukamoto, “Illuminating device for microscopes,”U.S. patent4,852,985 (August1, 1989).

Nussmeier, T. A.

T. A. Nussmeier, “Interferometric distance measurement method,”U.S. patent4,355, 899 (October26, 1982).

Shimada, Y.

T. Fujihara, Y. Shimada, C. Nagano, K. Tsukamoto, “Illuminating device for microscopes,”U.S. patent4,852,985 (August1, 1989).

Smorenburg, C.

Smythe, R. A.

J. F. Biegen, R. A. Smythe, Surf. Topography 1, 469 (1988).

Tsukamoto, K.

T. Fujihara, Y. Shimada, C. Nagano, K. Tsukamoto, “Illuminating device for microscopes,”U.S. patent4,852,985 (August1, 1989).

van Wingerden, J.

Wyant, J. C.

J. C. Wyant, C. L. Koliopoulis, B. Bushan, D. Basila, J. Tribol. 108, 1 (1986).
[CrossRef]

Y. Y. Cheng, J. C. Wyant, Appl. Opt. 23, 4539 (1984).
[CrossRef] [PubMed]

Appl. Opt.

J. Opt. Soc. Am. A

J. Tribol.

J. C. Wyant, C. L. Koliopoulis, B. Bushan, D. Basila, J. Tribol. 108, 1 (1986).
[CrossRef]

Surf. Topography

J. F. Biegen, R. A. Smythe, Surf. Topography 1, 469 (1988).

Other

T. A. Nussmeier, “Interferometric distance measurement method,”U.S. patent4,355, 899 (October26, 1982).

T. Fujihara, Y. Shimada, C. Nagano, K. Tsukamoto, “Illuminating device for microscopes,”U.S. patent4,852,985 (August1, 1989).

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 (6)

Fig. 1
Fig. 1

Layout of the LED source assembly showing locations of the primary- and secondary-wavelength LED’s.

Fig. 2
Fig. 2

Basic LED electrical schematic. VF(λ1,2) are the two points where the LED voltage drops are measured for temperature compensation. The analog switch controls which LED group is energized.

Fig. 3
Fig. 3

Results of repeated LED source calibrations for both wavelengths.

Fig. 4
Fig. 4

Power spectrum of the intensity fluctuations of the LED source compared with that of a commercial microscope halogen lamp.

Fig. 5
Fig. 5

Schematic diagram of an optical profiler that uses the LED source.

Fig. 6
Fig. 6

Measurement of a grating from a 1.75-μm step-height standard by multiwavelength phase-shifting interferometry with an optical profiler that uses the LED source. The average measured height was 1.74 μm.

Equations (2)

Equations on this page are rendered with MathJax. Learn more.

I F = I 0 exp ( q V F α k T ) ,
T 2 = T 1 V F ( T 2 ) V F ( T 1 ) .

Metrics