Abstract

Sensitivity and accuracy of measurements made by the moiré effect can be increased by a fringe multiplication factor. For a given displacement or deformation, the number of fringes that cross the field is increased by this factor. Multiplications as high as thirty are demonstrated. High sensitivity measurements are possible with coarse active gratings. With two amplitude gratings of equal nominal frequencies multiplication patterns exhibiting pure two-beam interference are produced when transmittance is 0.5. With gratings in which frequencies are dissimilar by integral factor β, multiplication by is achieved, where b is an integer. Guild’s theory of moiré fringes is extended to this case of grossly dissimilar grating frequencies. The combination of a symmetrical double-order blazed reference grating with a coarse bar-and-space active grating appears most attractive for many metrological applications.

© 1967 Optical Society of America

Full Article  |  PDF Article

References

  • View by:
  • |
  • |

  1. J. Guild, The Interference Systems of Crossed Diffraction Grating—Theory of Moiré Fringes (Oxford University Press, London, 1956).
  2. D. Post, Exp. Mech.7, to be published.

Guild, J.

J. Guild, The Interference Systems of Crossed Diffraction Grating—Theory of Moiré Fringes (Oxford University Press, London, 1956).

Post, D.

D. Post, Exp. Mech.7, to be published.

Other (2)

J. Guild, The Interference Systems of Crossed Diffraction Grating—Theory of Moiré Fringes (Oxford University Press, London, 1956).

D. Post, Exp. Mech.7, to be published.

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

Optical system.

Fig. 2
Fig. 2

Multiplication by odd factors one (a), five (b), and eleven (c), exhibiting two-beam interference.

Fig. 3
Fig. 3

Multiplication by ten (a) and fifteen (b), exhibiting effects of secondary wavefronts.

Fig. 4
Fig. 4

Subdivision of an incident ray diffracted by gratings whose frequencies are dissimilar by an integral factor.

Fig. 5
Fig. 5

(a) Multiplication by factor of twenty with 2400 rulings/cm double-order blaze analyzer and 120 rulings/cm active grating. (b) Multiplication by factor of thirty with 2400 rulings/cm single-order blaze analyzer and 80 rulings/cm active grating.

Fig. 6
Fig. 6

Multiplication by factor of twenty-five with 400 rulings/cm analyzer and 80 rulings/cm active grating.

Metrics