Abstract:
In order to alleviate the inherent contradiction of existing deformable mirror (DM)-based adaptive freeform surface interferometers, which can not take into account both large departure coverage and DM surface monitoring, therefore, adaptive ring-cavity compensator (ARCC) was proposed, which can generate large departure wavefront using DM deformation multiple times, and it had been preliminarily verified. Considering the practical application of ARCC and the fact that most freeform surfaces in optical systems were low-order aberration surfaces, the low-order aberration compensation characteristics of ARCC were verified and studied. Firstly, the compensation capability of ARCC and TSRC (traditional single round compensator) for astigmatism, coma and spherical aberration was compared by Zemax modeling. It was concluded that the ability of ARCC to compensate astigmatism and coma were about twice that of TSRC, and the ability of ARCC to compensate spherical aberration was also significantly greater than TSRC, which verified the advantage of ARCC in low-order aberration compensation; Secondly, the low-order aberration compensation of ARCC was studied, and it was include that the aberration types on DM in ARCC structure was one-to-many or many-to-one with the aberration types compensated to the tested surface. The results show that in practice, four low-order aberration free-form surfaces are compensated and verified by using ARCC and TSRC respectively. Under the same DM stroke variable, ARCC shows more excellent low-order aberration compensation ability than the TSRC.