RONCHI

History

1970  Onwards

GOTO   RONCHI   INDEX

Copyright – P. J. Smith

But permission is given to distribute this material in unaltered form as long as it is not sold for profit.


Massive computing power, special needs

and stranger and stranger tests.

 

 

While some simple ingenious solutions appeared, the main push was to special applications guided by a far better understanding of wave optics.

 

Holographic tests and variations appeared.  Some variants entirely eliminated the double image usually associated with a Ronchi test.  Most of these are far too complex for casual use and often require special components.  The uses of phase shifting techniques appear and is now common. Of course, a simple scan of the Ronchi grating across a surface is an old technique used by experienced testers which predates phase shifting methods.

 

Some of the techniques have been either used or investigated by large companies – often doing government work – and the information has sometimes been regarded as ‘in house’ information.  This may appear in papers years after the original work was done and often in sketchy form.  Some is the result of the ‘Cold War’.

 

Some tests mentioned here are so far removed from the original Ronchi test that it is hard to justify their inclusion.  Usually the deciding feature is that the test uses a grating (or single wire).

 

In some interferometric tests a grating is used simply as a beam splitter.  Casual observation will relate it to a Ronchi test but closer examination often rejects this classification.

 

I must admit that in some cases, interest rather than a more careful classification has caused the inclusion of some of these tests.

 

Newer computing methods were now available to individuals.

 

Many of the developments are so specialized that they have little relevance to ATM’s.  They are listed for completeness but few details are given except in special cases of interest.  

 

 



 

1970. A. Cornejo and D. Malacara, Appl. Opt.  9, 1897, (1970).    "Ronchi Test of Aspherical Surfaces, Analysis and Accuracy".  Looks at the sensitivity and expected accuracy.  Interesting.

 

1970. A. S. DeVany, Appl. Opt. 9, 1944 (1970).    "Quasi-Ronchigrams as Mirror Transitive Images of Interferograms"  Classifies Ronchi patterns for ease of qualitative surface interpretation by opticians.

 

1970. H. Salzmann. Appl. Opt. 9, 1943, (1970).    "A Simple Interferometer Based on the Ronchi Test"

 

1970. A. S. DeVany. Appl. Opt. 9, 1219, (1970).    "Supplement to: Some Aspects of Interferometric Testing and Optical Figuring"  Classifies Ronchi patterns for ease of qualitative surface interpretation by opticians.

 

1970. A. S. DeVany. Appl. Opt. 9, 1720, (1970).    Supplement to: Aberration Analysis by Double Wire Testing"

 

1971. D. Malacara and A. Cornejo.  Appl. Opt. 10, 679, (1971).    "Modified Ronchi test to Measure the Axial Chromatic Aberration in Lenses".  A simple and interesting idea.  May have some application.

 

1971. M. V. R. K. Murty. Bull. Opt. Soc. India. 5, 1, (1971).    "A Simple Method of Introducing Tilt in the Ronchi and Cube Type Shearing Interferometers".  Not really about Ronchi Testing but interpretation can be similar.

 

1971. S. Yokozeki and T. Suzuki. Appl. Opt. 10, 1575, (1971).    "Shearing Interferometer Using the Grating as the Beamsplitter"

 

1972. G. M. Popov. Izv. Krym. Astrofiz. Obs. 45, 188, (1972).    "Methods of Calculation and Testing of Ritchey- Chretien Systems". Interesting article which uses unequally spaced circular gratings.  When the surface is correct, the Ronchi image is of equally spaced circles. See non linear gratings.

 

1972, Briers, J. D.  Opt Laser Technology 4, 28 – 41.  “Interferometric Testing of Optical Components: a Review”

 

1973. M. V. R. K Murty. Appl. Opt. 12, 2230, (1973).    "Sharpening the Fringes in the Ronchi Test"  Uses gratings other than equal dark-light spaces.  See non linear gratings.

 

1973. J. C. Wyant. Appl. Opt. 12, 2057, (1973).    "Double Frequency Grating Lateral Shear Interforometer" Uses holographic techniques.  Removes any overlapping images.

 

1973. D. Nyyssonen and J. M. Jerke. Appl. Opt. 12, 9, 2061, (1973).    "Lens Testing with a Simple Wavefront Shearing Interferometer"    (Not about Ronchi testing but interpretation methods are similar)

 

1974. D. Malacara and A. Cornejo. Appl. Opt. 13, 8, 1778, (1974).    "Null Ronchi Test for Aspherical Surfaces" Malacara places the ‘Mobsby’ grating theory on correct footing.  See non linear gratings.

 

1974. A. S. De Vany. 13, 2, 229, (1974).    "Testing the Sphericity of Short Radii Convex Surfaces"  Describes a microscope test rig for testing miniature convexes and concaves.  A ronchi test is possible.  See advanced set-ups.

 

1974. L. Ghozeil and J. E. Simmons. 13, 8, 1773, (1974).    "Screen Test for Large Mirrors"   (Hartmann like square grid is related in many ways to Ronchi Tests). See non linear gratings for a little more information.

 

1974. A. S. De Vany. 13, 8, 1737, (1974).    "Eight Way Classification of Interferential Fringes - Supplement"  More classisfications to make interpretation of Ronchi patterns easy for the optician.  De Vany gets carried away with this.

 

1974. De Vany's - Ball Bearing Sources in conjunction with a Ronchi Grating to assess optical systems.  It is impossible here to use a Grating/Grating test.  A useful technique.  See pinhole sources for more information.

 

1977. George W. Hopkins and Richard N. Shagam. Appl. Optic. 16, 10, 2602, (1977).    "Null Ronchi Grating from Spot Diagrams". An interesting technique for designing Mobsby gratings using a raytracing program.  Since this is more readily available now the technique is of interest.  It can be extended to all of the non linear gratings.  See non linear gratings for more details.

 

1978. De Vany. Appl. Optic. 17, 19, (1978).    "Profiling Pitch Polishers".  Methods of interpreting Ronchi tests and figuring via lap modification. He preferred a Slit/Grating in this application but also mentioned the possibilities

of a Grating/Grating test.

 

1978. Daniel Malacara and Michel Josse. Appl. Optic. 17, 1, (1978).    "Testing of Aspherical Lenses using Side Band Ronchi Test". 

 

1979. De Vany Appl. Optic. 18, 5, (1979).    Testing Schmidt Cassegrains and mentions that if a Slit source is used, assessment may use either a Ronchi grid or a Knife edge.  Old methods revisited but useful knowledge.

 

1979, Briers, J. D.  Opt Laser Technology 11, 189 - 196. “Ronchi Test Formula : Theory”. Excellent article covering most aspects of Ronchi testing especially relating to interpretation of each aberration.  This is extended in the next reference.

 

1972, Briers, J. D.  Opt Laser Technology 11, 245 - 257. “Ronchi Test Formula 2 : Practical Formula and Experimental Verification”.  Actually form defects on surfaces and test both by interferometric and Ronchi.  Gives methods of quantitatively estimating surface defects from Ronchigrams.  This is the basis of my program RonchiEstimates.  See software.

 

1981. J. Schwinder. Appl. Optic. 20, 15, (1981).   "Single Sideband Ronchi Tests".

 

1981. De Vany  Appl. Optic. Mainly about interpretation of Ronchigrams.

 

1984. Kevin G. Harding and Steven Cartwright. Appl. Optic. 23, 10, 1517, (1984).    "Phase Grating use in Moire Interferometry".

 

1986. Krzysztof Patorski and Alejandro-Cornejo-Rodriguez. Appl. Optic. 25, 16, 2790, (1986).    "Fringe Contrast Interpretation for an Extended Source Ronchi Test".

 

1986. Krzysztof Patorski. Appl. Optic. 25, 22, 4192, (1986).    "Grating Shearing Interferometer with Variable Shear and Fringe Orientation".

 

1986. Krzysztof Patorski and Alejandro-Cornejo-Rodriguez. Appl. Optic. 25, 13, 2031, (1986).    "Ronchi Test with Daylight Illumination".  This simply mentions how part of a a grating may be backed with white paper or Alfoil and used in daylight in the grating/grating mode.  Actually is a rehash of Lincoln Davis’s method reported in 1935 by Ingalls, Scientific American, Mar 1935. 

 

1989. Qing-Shin Ru et al.  Appl. Optic. 28, 15, 3350, (1989).    "Constant Radial Shearing Interferometry with Circular Gratings".

 

1990 Qing-Shin Ru et al.  Appl. Optic. 29, 22, 3255, (1990)   "Ronchi Test and a New Phase Reduction Algorithm".

 

1990 Jen-An Lin, T. Yeh. and S. W. HsAlberto Cordero-Davila et al.  Appl. Optic. 29, 31, 4618, (1990)

   "Null Hartmann and Ronchi-Hartmann Tests". Interesting.  See non linear gratings.

 

1990 Alberto Cordero-Davila et al.  Appl. Optic. 29, 31, 4618, (1990).    "Null Hartmann and Ronchi-Hartmann Tests".  Interesting. See non linear gratings.

 

1990 Alberto Cordero-Davila et al.  Appl. Optic. 29, 25, 3633, (1990).    "Analysis of the Interferometric Ronchi Test".

 

1990. Qing-Shin Ru et al.  Appl. Optic. 29, 22, 3255, (1990).    "Ronchi Test and a New Phase Reduction Algorithm".

 

1992. Alberto Cordero-Davila et al.  Appl. Optic. 31, 13, 2370, (1992).    "Ronchi and Hartmann Tests with the Same Mathematical Theory".  Very interesting.  It views Ronchi and Hartman masks as complimentary using a common mathematical analysis for both.  This is a fertile field of experiment for alternatives to a Mobsby Grating.  See non linear gratings for some more details.

 

1992. Kuppaswamy Venkatesan et al.  Appl. Optic. 31, 28, 5984, (1992).    "Direct Determination of Focal Length by Using Talbot Interferometry".

 

1995. Cordero, Luna et al.  Appl. Optic. AUNAM, RT - 95 - 02, (1995).    "Evaluation de la Calidad de la Imagen del Telescopio de 2.1 m"   Uses a regularly spaced array of holes in conjunction with a pinhole.

 

1997.  Masud Mansuripur.  A brief look at the Ronchi Test on the 100th anniversary of Ronchi's birth.  Uses simulations to show typical Ronchi images using both fine and coarse grids.  Published on the web.

 

1998. Cordero and Davila et al. Appl. Optic. 37, 4, 672, (1998).   "Ronchi Test with a Square Grid".   Describes a two dimensional Ronchi Test using a 2D Ronchi Grid.  The reduction of surface errors over the entire aperture is discussed. For the type of patterns involved see woven gratings.

 

1998.  L. J. Fellows and S. Gungor.  Meas. Sci. Technol. 9, 1963-1969, (1998).  "Fabrication of Photoresist Diffraction Gratings"

   

 


 

GOTO   RONCHI   INDEX