Abstract

Appending gradient-index matching regions and apodization, which is an amplitude modulation of the rugate sinusoidal index profile, are two effective means to reduce and nearly eliminate the sidelobes. When a combination of these methods is used in the rugate design, the resulting filter will have good sidelobe suppression both near to and far from the stopband and will have high reflectance in the stopband.

© 1989 Optical Society of America

Full Article  |  PDF Article

References

  • View by:
  • |
  • |
  • |

  1. A. Thelen, “Design of Optical Minus Filters,” J. Opt. Soc. Am. 61, 365–369 (1971).
    [CrossRef]
  2. L. Young, “Multilayer Interference Filters with Narrow Stop Bands,” Appl. Opt. 6, 297–315 (1967).
    [CrossRef] [PubMed]
  3. W. H. Southwell, “Spectral Response Calculations of Rugate Filters using Coupled-Wave Theory,” J. Opt. Soc. Am. A 5, 1558–1564 (1988).
    [CrossRef]
  4. W. H. Southwell, R. L. Hall, “Rugate Filter Sidelobe Suppression using Quintic and Rugated Quintic Matching Layers,” Appl. Opt. 28, 2949–2951 (1989).
    [CrossRef] [PubMed]
  5. J. A. Dobrowolski, D. Lowe, “Optical Thin Film Synthesis Program based on the use of Fourier Transform,” Appl. Opt. 17, 3039–3050 (1978).
    [CrossRef] [PubMed]

1989

1988

1978

1971

1967

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

(a) Index profile for a fifty-cycle rugate on a glass substrate and with air incidence medium. (b) Reflectance of the rugate. Notice the high sidelobes near and far from the stopband.

Fig. 2
Fig. 2

(a) Fifty-cycle rugate with three cycles on each end matched with rugated quintics. (b) Reflectance of the corresponding rugate. Notice the reduced sidelobes far from the stop band; because of the fixed wavelength sample density, the sidelobes at low wavelengths are not resolved.

Fig. 3
Fig. 3

(a) Fifty-cycle rugate with linear apodization and rugated quintics of each side. (b) Reflectance of the corresponding rugate. Notice the reduced sidelobes far from the stopband and the two sidelobes near the stopband.

Fig. 4
Fig. 4

(a) Fifty-cycle rugate with Gaussian apodization with one over e-squared truncation plus the three-cycle rugated quintics. (b) Reflectance of the corresponding rugate. Notice the broader stopband as compared to the linear apodization and the reduced sidelobes next to the stopband.

Fig. 5
Fig. 5

(a) Fifty-cycle rugate with quintic apodization plus the quintic matching regions. (b) Reflectance of the corresponding rugate. Note the virtual elimination of all sidelobes both near and far from the stopband.

Fig. 6
Fig. 6

(a) Fifty-cycle rugate with partial Gaussian apodization and quintic matching regions. Only the first and last ten cycles are modified. (b) Reflectance of the corresponding rugate. The reflectance in the stopband is considerably higher than the fully apodized rugate shown in Fig. 4, yet there is good near and far sidelobe suppression.

Equations (1)

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

Δ λ / λ = n p / ( 2 n a ) ,

Metrics