Simulations of an etched spiral axial attenuation scheme for an on-axis reflecting telescope

10th International LISA Symposium

Spector, Aaron^1 ; Mueller, Guido^1

Department of Physics, University of Florida, United States^1

关键词: Current generation;    Gravitational wave detectors;    Primary mirrors;    Reflected power;    Reflecting telescopes;    Secondary mirror;    Telescope design;    Telescope structures;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/610/1/012030/pdf
DOI  :  10.1088/1742-6596/610/1/012030

来源: IOP

【 摘 要 】

The current generation of proposed space based interferometric gravitational wave detectors all use a reflecting telescope to transfer the laser signals between the space- craft. One of the proposed telescope designs is an on-axis classical Cassegrain with the secondary mirror axially aligned to the primary mirror. Since the outgoing beam will be incident normal to the secondary, some of the light will be reflected directly back to the optical bench. Length changes between the telescope structure and the optical bench will cause this back-reflected light to introduce phase noise to the measurement signal. The phase noise from this process must be suppressed below 0.1 μcycles / √Hz to meet the LISA requirements. We have presented simulations that demonstrate that the back-reflected power can be sufficiently attenuated by using a specifically patterned Anti-Reflective (AR) region, in the shape of a spiral, at the center of the secondary mirror.