Zygo Corporation is a company that specializes in optical systems & equipment for areas such as optical metrology. Zygo's metrology systems are based on optical interferometry measuring displacement, surface figure, and optical wavefront. Metrology and optical markets for end-user and OEM applications include semiconductor capital equipment, aerospace/defense, automotive, and research.Zygo Corporation is listed on NASDAQ and traded under the symbol ZIGO. It is headquartered at Middlefield, Connecticut, and has 484 employees worldwide. Wikipedia.
Deck L.L.,Zygo Corporation
Applied Optics | Year: 2014
A general method of surface profiling with phase-shifting interferometry techniques uses iterative linear regression to fit the sequence of interferograms to a physical model of the cavity. The physical model incorporates all important cavity influences, including environmentally induced rigid-body motion, phase shifter miscalibrations, multiple interference, geometry-induced spatial phase-shift variations, and their cross-couplings. By incorporating an initial estimate of the surface profile and iteratively solving for space- and time-dependent variables separately, convergence is robust and rapid. The technique has no restriction on surface shape or departure. © 2014 Optical Society of America.
De Groot P.J.,Zygo Corporation
Applied Optics | Year: 2014
High-performance data processing algorithms for phase-shifting interferometry accommodate adjustment errors in the phase shift increment as well as harmonic distortions in the interference signal. However, a widely overlooked error source is the combination of these two imperfections. Phase shift tuning errors increase the sensitivity of phase estimation algorithms to second-order and higher harmonics present in Fizeau interference signals. I derive an analytical formula for evaluating these errors more realistically, in part to identify the characteristics of the optimal PSI algorithm. Even for advanced algorithms, it is found that multiple reflections increase the error contribution of detuning by orders of magnitude compared with the two-beam calculation and impose a practical limit of 30% in tuning error for sub-nm metrology in a 4%-4% Fizeau cavity. Consequently, a preferred approach for high precision spherical cavities is to use either wavelength tuning in place of mechanical phase shifting or an iterative solver that accommodates unknown phase shifts as a function of field position. © 2014 Optical Society of America.
de Groot P.,Zygo Corporation
Advances in Optics and Photonics | Year: 2015
Interference microscopy plays a central role in noncontact strategies for process development and quality control, providing full 3D measurement of surface characteristics that influence the functional behavior of manufactured parts. Here I briefly review the history and principles of this important technique, then concentrate on the details of hardware, software, and applications of interference microscopy using phase-shifting and coherence scanning measurement principles. Recent advances considered here include performance improvements, vibration robustness, full color imaging, accommodation of highly sloped surfaces, correlation to contact methods, transparent film analysis, and international standardization of calibration and specification. © 2015 Optical Society of America.
Zygo Corporation | Date: 2015-07-14
Determining information about a degree of freedom of rigid body motion of an encoder scale includes: directing a first beam toward an encoder scale, in which the first beam diffracts from an encoder scale; combining a diffracted component of the first beam with a second beam to form an interfering output beam; monitoring changes in the output beam as a function of a wavelength of the first and second beams; and determining the information about a degree of freedom of rigid body motion of the encoder scale based on changes in the output beam as a function of the wavelength.
Zygo Corporation | Date: 2015-10-12
An encoder interferometry system includes an encoder scale arranged to receive and diffract a measurement beam. The system further includes one or more optical elements configured and arranged to receive a first diffracted measurement beam and a second diffracted measurement beam from the encoder scale and to redirect the first diffracted measurement beam and the second diffracted measurement beam toward the encoder scale such that the first diffracted measurement beam and the second diffracted measurement beam propagate along non-parallel beam paths having an angular separation following a second diffraction at the encoder scale. The system further includes a first detector arranged to receive the first diffracted measurement beam and a second detector arranged to receive the second diffracted measurement beam.