Subaperture stitching for measurement of freeform wavefront

Pant, Kamal K.; Burada, Dali R.; Bichra, Mohamed; Singh, Mahendra; Ghosh, Amitava; Khan, Gufran S.; Sinzinger, Stefan; Shakher, Chandra

doi:10.1364/ao.54.010022

Cited by 48 publications

(5 citation statements)

References 20 publications

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“…Its designed profile is described by a seventh-order polynomial having a maximum sag of 1.119 mm. It has been fabricated on PMMA by ultraprecision machining at the Institute for Micro and Nanotechnologies (IMN) at the Technische Universität Ilmenau in Germany [3]. The used amplitude grating with a grating period of 50µm for this experiment was fabricated by means of lithography.…”

Section: Experimental Validationmentioning

confidence: 99%

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Wavefront sensing by numerical evaluation of diffracted wavefields

et al. 2016

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A novel wavefront sensor principle based on decomposition of the angular spectrum propagator and Fourier analysis is presented. A wavefront is propagated to a 2 dimensional binary cross grating. The appropriate diffraction orders are filtered out and captured by a CCD camera. The following Fourier analysis delivers maps of phase gradients in the x and y coordinates. We verify the presented method by numerical tests and experimentally in a measurement setup on the example of a wavefront generated by a cubic phase element in transmission and reflection. We compared the results of our principle with a commercial Shack-Hartmann wavefront sensor.

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Section: Experimental Validationmentioning

confidence: 99%

“…At the same time, free-form elements open a wide field of additional functionalities allowing the minimization of the number of required components, size and weight of the system. The fabrication of highprecision free-form surfaces requires new production techniques as well as new appropriate metrology procedures and systems [2] [3].…”

Section: Introductionmentioning

confidence: 99%

Wavefront sensing by numerical evaluation of diffracted wavefields

et al. 2016

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“…Therefore, in recent years, many scholars have studied the optical testing methods of free-form surfaces. Thus, a number of metrology methods have been developed [7][8][9], and these methods are roughly divided into contact metrology and non-contact metrology. Because it is easy to scratch the surfaces with contact metrology, non-contact metrology is preferred for high-precision optical surfaces.…”

Section: Introductionmentioning

confidence: 99%

Measurement of Small-Slope Free-Form Optical Surfaces with the Modified Phase Retrieval

Wang

et al. 2022

Micromachines

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In this paper, we demonstrate the use of the modified phase retrieval as a method for application in the measurement of small-slope free-form optical surfaces. This technique is a solution for the measurement of small-slope free-form optical surfaces, based on the modified phase retrieval algorithm, whose essence is that only two defocused images are needed to estimate the wave front with an accuracy similar to that of the traditional phase retrieval but with less image capturing and computation time. An experimental arrangement used to measure the small-slope free-form optical surfaces using the modified phase retrieval is described. The results of these experiments demonstrate that the modified phase retrieval method can achieve measurements comparable to those of the standard interferometer.

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“…is has changed however in recent years, which can be easily noticed through the common availability of progressive lenses [9,10]. Capabilities of precise multiaxis machine tools increased to the level where completely asymmetrical optics can be manufactured [11,12]. It created new prospects for light shaping possibilities.…”

Section: Introductionmentioning

confidence: 99%

“…Considering (11) in (10), one obtains the fully nonlinear elliptic partial differential equation of Monge-Ampere type (MA PDE):…”

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confidence: 99%

Simplified Geometric Approach to Freeform Beam Shaper Design

Wojtanowski

Drozd

2020

International Journal of Optics

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Beam of light shaping process can be considered ultimate, if both irradiance and wavefront spatial distributions are under control and both can be shaped arbitrarily. In order to keep these two quantities determined simultaneously, it is required to apply at least two powered refractive or reflective surfaces. In this paper, a fully geometric design method of double-freeform beam shapers is discussed briefly. The presented algorithm is based on two stages. First, integrable input-output ray mapping is calculated by the application of the novel GATMA (Geometric Approach to Monge–Ampere equation) method. It allows us to determine the shape of the first freeform surface. Then, according to the condition of constant optical path length between input and output plane, corrected by wavefront phases at those planes, the second surface is determined. GATMA algorithm combines advantages of Monge–Ampere (MA) equation and ray-tracing efficient apparatus. Compared to the state-of-the-art freeform design methods, GATMA does not need to solve MA equation directly but uses this equation as an error function. Such approach makes the computation algorithm simpler and more robust and convergent. The application of the proposed method in a challenging design example of a beam shaper, transforming uniform collimated beam into a beam having a triangular cross section and flat wavefront, is presented as a case study.

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Subaperture stitching for measurement of freeform wavefront

Cited by 48 publications

References 20 publications

Wavefront sensing by numerical evaluation of diffracted wavefields

Wavefront sensing by numerical evaluation of diffracted wavefields

Measurement of Small-Slope Free-Form Optical Surfaces with the Modified Phase Retrieval

Simplified Geometric Approach to Freeform Beam Shaper Design

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