Testing Concave Aspheric Surface With Computer Generated Holography

Compared with spherical surface,an aspheric surface has better optical performance, for example geometrical focus of reflecting surface of quadric surface are a couple of non-aberrational points,and it is concentric for the refracted beam from refracting surface. In addition,the aspheric surface enables to have more adjustable parameters in optical design to satisfy different optical systems.Those properties can greatly be improved the performance of optical system,including image quality enhancement,miniaturized system, and lightweight.Therefore,the application of aspheric surface is getting more and more widespread.However,its application has been limited by optical manufacture and testing technology for a long time.Although the current machining technology has been developed rapidly,the level of testing is relatively out of date,and as a whole,is not able to satisfy the application requirement timely.There are many methods in the testing of aspheric surface, but they have the different limitation respectively.The thesis argues that:firstly,it is represented that the fundamental theory,the characteristic and the application of the aspheric surface,and the existing testing methods are introduced and compared in this thesis.Secondly,it sets forth the principle,manufacture and reappearance of computer generated hologram(CGH),and also to validate through experiments based on the elementary theory of optical holography and computer-generated holography.The whole process of CGH for aspheric surface testing is simulated before the experiment.Finally,it introduces the fundamentals,the experimental processes of CGH for aspheric surface testing,and to analyze the experimental results.The thesis also shows other methods for testing aspheric surface which validates our results,comparing with CGH for aspheric surface testing.The main innovation of this thesis is as follows:1.We simulated the whole process of CGH for aspheric surface testing,and it avoids a large number of complex pretrial,and offers the helpful and reference for the practicable optical testing.2.We processed the phase-shifting not with reference mirror but with CGH which simplified the experimental devices when we gather image.We obtained the better results, after the processing of the experimental results.3.We put forward to reconstruct the amplitude and the phase of optical field (including speckle noise)with digital holographic technology,aim at the noise in the optical field of digital holography,and then eliminate speckle noise to gain the way to high-quality optical field.The experimental result indicated that it is still satisfying to obtain the light field with this method even if the speckle noise is very heavy.