Abstract
Optical choppers with rotating wheels are some of the most used macroscopic optomechatronic devices for the controlled modulation, attenuation or obscuration of light in a wide area of applications. We discuss and compare the modulation functions produced by two types of chopper wheels: the classical device, with windows with linear edges, and the eclipse chopper (with windows with circular edges) that, to the best of our knowledge, we have introduced. This discussion is based on the analysis and the design we have previously developed for these various devices, for top-hat (constant over the entire section) light beam distributions. While the comparison of the different shapes of transmitted signals allows for the proper choice of the most appropriate device and parameters to obtain the modulation function that is fit for a certain application, the present work also presents the mechanical setup we have designed and manufactured for testing choppers with rotating wheels. A series of prototype wheels with different, optimized profiles were obtained for the purpose. The simulation and the electro-erosion programs for the wire electro-erosion of aluminum plates to manufacture the wheels are presented. An advantageous double wheel solution has been developed to obtain wheels with windows of different shapes and sizes, and the testing of this final assembly concludes the study.
Highlights
Choppers [2] are optomechatronic devices used for the controlled modulation or attenuation of light – especially for laser radiation
We have introduced in this respect a new type of chopper wheel, with windows with circular edges [11, 13], and we have demonstrated that it allows for producing modulation functions that are different from those that may be obtained with the classical wheels
We have discussed the modulation functions produced by different configurations of chopper wheels, from the classical ones to the eclipse choppers that, to the best of our knowledge we have introduced [13]
Summary
Choppers [2] are optomechatronic devices used for the controlled modulation or attenuation of light – especially for laser radiation. We have obtained analytically the modulation functions and have developed the designing calculus of all the possible cases of the established configuration of chopper wheels, with windows with linear edges (Fig. 1a, b, Table 1) [9], for top-hat (constant over the entire section) light beam distribution. A comparative look with regard to the classical configuration will be made in this paper, achieving a synthesis of our previous studies The scope of this discussion on the different shapes of transmitted signals produced by various types of choppers is to provide rules-of-thumb to choose the most appropriate device and its characteristic parameters to obtain the modulation functions that are necessary for a certain application.
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