Polar-coordinate laser writing systems: error analysis of fabricated DOEs

Diffractive optics is a field where the progress is defined by fabrication technology. Diffractive optical elements (DOEs) are generally planar structures, typically fabricated using X-Y image generators designed for semiconductor industry. However there are some kinds of DOEs for which the polar scanning geometry, where the optic rotates under a writing beam, is more preferable. In some cases polar coordinate machines provide the only practical method of fabricating DOEs with the required accuracy. It is necessary to take into account the DOE specification when choosing the fabrication method. The present paper considers peculiarities of polar coordinate laser systems for large size and high precision DOEs fabrication. The specific error sources for these systems are described and compared with those of X-Y systems. An optimal writing strategy is discussed. The wavefront aberrations of rotationally symmetric DOEs caused by fabrication errors were measured interferometrically. Different types of aberrations were identified and can be referred to certain writing errors. Interferometric measurements of the wavefront errors for binary zone plates with a 64 mm diameter and 0.45 numerical aperture have shown that the wavefront root-mean-square error does not exceed 0.009 (lambda) wavelength.

[1]  H. Nishihara,et al.  Laser beam lithographed micro-Fresnel lenses. , 1990, Applied optics.

[2]  Shigeo Ozono,et al.  An instrument for manufacturing zone-plates by using a lathe , 1994 .

[3]  James H. Burge,et al.  Measurement of large convex aspheres , 1997, Other Conferences.

[4]  O. Bryngdahl,et al.  Computer-generated holograms: carrier of polar geometry. , 1985, Applied optics.

[5]  Sharlene A. Liu,et al.  Polar-coordinate laser writer for binary optics fabrication , 1990, Photonics West - Lasers and Applications in Science and Engineering.

[6]  M Yoneda,et al.  Electron-beam writing system and its application to large and high-density diffractive optic elements. , 1994, Applied optics.

[7]  Cynthia L. Vernold,et al.  Technique for aligning optical and mechanical axes based on a rotating linear grating , 1995 .

[8]  James H. Burge,et al.  Processing parameter optimization for thermochemical writing of DOEs on chromium films , 1997, Photonics West.

[9]  Rolf Freimann.  Aberrations of axially symmetric diffractive optical elements in relation to their fabrication inaccuracies , 2000 .

[10]  Peter D. Buck,et al.  Optimizing the use of multipass printing to minimize printing errors in advanced laser reticle-writing systems , 1995, Photomask Technology.

[11]  James H. Burge,et al.  Error analysis for CGH optical testing , 1999, Optics + Photonics.

[12]  A. Friberg,et al.  Holographic generation of diffraction-free beams. , 1988, Applied optics.

[13]  Victor Pavlovich Korolkov,et al.  Requirements and approaches to adapting laser writers for fabrication of gray-scale masks , 2001, SPIE Optics + Photonics.

[14]  Bowen Jp,et al.  Generation of large-diameter diffractive elements with laser pattern generation , 1997 .

[15]  James H. Burge,et al.  Applications of computer-generated holograms for interferometric measurement of large aspheric optics , 1995, Other Conferences.

[16]  Steven M. Arnold,et al.  Verification and certification of CGH aspheric nulls , 1995, Optics & Photonics.

[17]  A G Verhoglyad,et al.  Polar coordinate laser pattern generator for fabrication of diffractive optical elements with arbitrary structure. , 1999, Applied optics.