Collimation method using a double grating system

Thumbnail Image
Full text at PDC
Publication Date
Torcal Milla, Francisco José
Salgado Remacha, Francisco Javier
Morlanes Calvo, Tomás
Jiménez Castillo, Isidoro
Bernabeu Martínez, Eusebio
Advisors (or tutors)
Journal Title
Journal ISSN
Volume Title
The Optical Society Of America
Google Scholar
Research Projects
Organizational Units
Journal Issue
We present a collimation technique based on a double grating system to locate with high accuracy an emitter in the focal plane of a lens. Talbot self-images are projected onto the second grating producing moiré interferences. By means of two photodetectors positioned just behind the second grating, it is possible to determine the optimal position of the light source for collimation by measuring the phase shift between the signals over the two photodetectors. We obtain mathematical expressions of the signal in terms of defocus. This allows us to perform an automated technique for collimation. In addition, a simple and accurate visual criterion for collimating a light source using a lens is proposed. Experimental results that corroborate the proposed technique are also presented.
© 2010 Optical Society of America. This research has been supported by project CCG08-UCM/DPI-3952 of Dirección General de Universidades e Investigación de la Consejería de Educación de la Comunidad de Madrid and by project DPI2008-02391 of the Ministerio de Ciencia e Innovación of Spain.
1. J. Jahns and A. W. Lohmann, “The Lau effect (a diffraction experiment with incoherent illumination)” Opt. Commun. 28, 263–267 (1979). 2. K. Patorski, “The self-imaging phenomenon and its applications”, Prog. Opt. 27, 3–108 (1989). 3. S. C. Som and A. Satpathi, “The generalized Lau effect”, J. Mod. Opt. 37, 1215–1226 (1990). 4. L. Liu, “Partially coherent diffraction effect between Lau and Talbot Effects”, J. Opt. Soc. Am. A 5, 1709–1716 (1988). 5. K. V. Avudainayagam and S. Chitralekha, “Lau effect and beam collimation”, J. Mod. Opt. 44, 175–178 (1997). 6. K. V. Avudainayagam and S. Chitra Nayagam, “Two-grating diffraction and Lau effect under laser illumination”, Appl. Opt. 36, 2029–2033 (1997). [PubMed] 7. Ch. Siegel, F. Loewenthal, and J. E. Balmer, “A wavefront sensor based on the fractional Talbot effect”, Opt. Commun. 194, 265–275 (2001). 8. C. L. Hou and J. Bai, “Wavefront measurement for long focal large aperture lens based on Talbot effect of Ronchi grating”, J. Phys.: Conf. Ser. 48, 1037–1041 (2006). 9. S. Chang, “Geometrical aberrations of self.imaged line gratings”, Optik (Jena) 116, 379–389 (2005). 10. S. Yokozeki and K. Ohnishi, “Spherical aberration measurement with shearing interferometer using Fourier imaging and moiré method”, Appl. Opt. 14, 623–627, (1975). [PubMed] 11. K. Patorski, S. Yokozeki, and T. Suzuki, “Collimation test by double grating shearing interferometer”, Appl. Opt. 15, 1234–1240, (1976). [PubMed] 12. J. P. Bétend-Bon, L. Wosinski, and M. Breidne, “Double grating phase stepping interferometry for testing aspherics”, Pure Appl. Opt. 1, 55–69 (1992). 13. J. C. Bhattacharya and A. K. Aggarwal, “Measurement of the focal length of a collimating lens using the Talbot effect and the moiré technique”, Appl. Opt. 30, 4479–4480 (1991). [PubMed] 14. S. Chang and S. I. Lee, “First-order aberration of a misfocused self-imaging system”, Optik (Jena) 119, 742–748 (2008). 15. S. Rana, S. Prakash, and S. Prakash, “Automated collimation testing in Lau interferometry using phase shifting technique”, Opt. Lasers Eng. 47, 656–661 (2009). 16. D. Joeux and Y. Cohen-Sabban, “High magnification self-imaging”, Appl. Opt. 21, 625–627 (1982). 17. Y. Cohen-Sabban and D. Joyeux, “Aberration-free nonparaxial self-imaging”, J. Opt. Soc. Am. 73, 707–719 (1983). 18. S. Szapiel and K. Patorski, “Fresnel diffraction images of periodic objects under Gaussian beam illumination”, Opt. Acta 26, 439–446 (1979). 19. L. M. Sánchez-Brea, J. Sáenz-Landete, J. Alonso, and E. Bernabéu, “Invariant grating pseudo-imaging using polychromatic light and finite extension source”, Appl. Opt. 47, 1470–1477 (2008).