Adjustable coherence depth in a geometrically desensitized interferometer

Proceedings of SPIE - The International Society for Optical Engineering

Volumn 3479, Issue , 1998, Pages 14-23

  De Groot, Peter J ^a   Deck, Leslie L ^a   Colonna De Lega, Xavier ^a  

^a Zygo   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

COHERENT LIGHT; HOLOGRAMS; INTERFEROMETRY; OPTICAL INSTRUMENTS;

FRINGE CONTRASTS; INCIDENT ANGLES; INTERFERENCE PATTERNS; OPTICAL GEOMETRIES; PLANE OF INCIDENCES; SPECTRAL PROPERTIES; TWO BEAMS;

INTERFEROMETERS;

EID: 2342644424     PISSN: 0277786X     EISSN: None     Source Type: Conference Proceeding    
DOI: 10.1117/12.316446     Document Type: Conference Paper

References (15)

1. J. Schwider, R. Burow, K.-E. Elssner, J. Grzanna, and R. Spolaczyk in the paper "Semiconductor wafer and technical flat planeness testing interferometer" (Appl. Opt. 25(7) 1117-1121 (1986)).
2. K. Lewotsky, "Grating interferometer measures large departures," Laser Focus World, 40-41 (April 1996).
3. P. de Groot, "Grating interferometer for flatness testing," Opt. Lett. 21(3) 228-230 (1996).
4. US Patent Nos. 5,526,116; 5,598,265; 5,671,050. Zygo Corporation manufactures a GDI instrument for industrial and data storage markets under the product name MESA.
5. The two-grating GDI instrument described in this paper is an evolutionary form of the holographic intererometer developed by P. Jacquot and P. M. Boone about ten years ago. See for example the paper entitled "Deux methodes holographiques appliquées au controle de planéitié," Proceedings OPTO 88, 313-319 (ESI Publications, Paris, 1988).
6. The white-light GDI interferogram in Fig.1 has enhanced fringe contrast to preserve the image quality in black and white photocopies. A more realistic image would show a gradual variation in intensity from fringe to fringe, but very little variation in fringe contrast over as many as 100 fringes.
7. th Edition (Pergamon Press, Oxford, 1987) p.32.
8. US and foreign patents pending.
9. In practice, the gratings shown in Fig.1 must be tilted slightly to deflect surface reflections. The grating tilts shift the position of best metrology, defined as the point of zero shear between beams A and B, away from the zero OPD position a fixed distance of 0.2mm. This phenomenon will be discussed in detail at the SPIE-sponsored Photonics East Conference in Boston (November 1-6, 1998).
10. Schwider, R. Burow, K.-E. Elssner, J. Grzanna, R. Spolaczyk and K. Merkel, "Digital wave-front measuring interferometry: some systematic error sources," Appl. Opt. 22(21), 3421-3432 (1983).
11. P. de Groot, "Metrology of transparent fiats" Meetings Digest, Optical Fabrication and Testing Workshop (Rochester, 1994).
12. P. de Groot, "Grating interferometer for metrology of transparent flats," Optical Fabrication and Testing Workshop, OSA 1996 Technical Digest Series, 7 28-30 (Boston, I 996).
13. C. Wyant, "How to extend interferometry for rough-surface tests," Laser Focus World, 131-135 (September, 1993).
14. T. Connolly, "Scanning interferometer characterizes surfaces" Laser Focus World, p.85 (August, 1995)
15. Us and foreign patents pending.