Computer generated hologram null compensator for optical metrology of a freeform surface

Talha, Muhammad; Chang, Jun; Wang, Yongtian; Cheng, Dewen; Zhang, Tingcheng; Aslam, Muhammad; Khan, Alan

doi:10.1016/j.ijleo.2009.09.009

Cited by 3 publications

(2 citation statements)

References 27 publications

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“…To measure the shape error of the off-axis aspheric surface at a high accuracy, researchers have offered several useful methods [3][4][5][6][7][8][9][10][11][12][13]. Wang Xiao-kun tested an off-axis ellipsoid mirror with sub-aperture stitching interferometry and applied least-squares fitting to process the test data, resulting in a 1.275λ of PV and 0.113λ of RMS [4].…”

Section: Introductionmentioning

confidence: 99%

“…As a null test technique, the computer generated hologram (CGH) method is a suitable compensator for off-axis aspheric surface measurement [9][10][11]. M. M. Talha measured a freeform surface with the CGH method with a result of PV = 0.0479λ [12]. Similarly, Li Fa-zhi used CGH as the aiding element to measure an off-axis high order aspheric surface [13].…”

Section: Introductionmentioning

confidence: 99%

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The Methods and Experiments of Shape Measurement for Off-Axis Conic Aspheric Surface

Zhang

Liu

et al. 2020

Materials

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The off-axis conic aspheric surface is widely used as a component in modern optical systems. It is critical for this kind of surface to obtain the real accuracy of the shape during optical processing. As is widely known, the null test is an effective method to measure the shape accuracy with high precision. Therefore, three shape measurement methods of null test including auto-collimation, single computer-generated hologram (CGH), and hybrid compensation are presented in detail in this research. Although the various methods have their own advantages and disadvantages, all methods need a special auxiliary component to accomplish the measurement. In the paper, an off-axis paraboloid (OAP) was chosen to be measured using the three methods along with auxiliary components of their own and it was shown that the experimental results involved in peak-to-valley (PV), root-mean-square (RMS), and shape distribution from three methods were consistent. As a result, the correctness and effectiveness of these three measurement methods were confirmed, which are very useful in engineering.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The Methods and Experiments of Shape Measurement for Off-Axis Conic Aspheric Surface

Zhang

Liu

et al. 2020

Materials

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Compensation Measurement Study for Aspherical Primary Mirror of Space Camera with CGH

Sun

Dong

2020

IOP Conf. Ser.: Mater. Sci. Eng.

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With the development of modern optical technology, demands on the performance of optical systems are increasing. Aspherical surfaces are widely used in space optical system considering its excellent ability in correcting aberrations, reducing the optical system weight and simplifying the optical construction. However, the interferometry of this kind of aspherical surface is difficult. To overcome the difficulty in testing aspherical primary mirror of space camera system, we provide a compensation method to accomplish the null testing of the aspherical primary mirror with CGH (Computer generated hologram). Our proposed method is introduced in detail in the theory part. In addition, we provide a detailed design for an actual parabolic surface. The results show that our proposed method can accomplish the testing of aspherical primary mirror in large aperture with satisfactory accuracy.

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Measurement investigation of an off-axis aspheric surface via a hybrid compensation method

Zhang

Liu

et al. 2018

Appl. Opt.

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Computer generated hologram null compensator for optical metrology of a freeform surface

Cited by 3 publications

References 27 publications

The Methods and Experiments of Shape Measurement for Off-Axis Conic Aspheric Surface

The Methods and Experiments of Shape Measurement for Off-Axis Conic Aspheric Surface

Compensation Measurement Study for Aspherical Primary Mirror of Space Camera with CGH

Measurement investigation of an off-axis aspheric surface via a hybrid compensation method

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