The second generation of gravitational wave detectors will aim at improving by an order of magnitude their sensitivity versus the present ones (LIGO and VIRGO). These detectors are based on long-baseline Michelson interferometer with high finesse Fabry-Perot cavity in the arms and have strong requirements on the mirrors quality. These large low-loss mirrors (340 mm in diameter, 200 mm thick) must have a near perfect flatness. The coating process shall not add surface figure Zernike terms higher than second order with amplitude >0.5 nm over the central 160 mm diameter. The limits for absorption and scattering losses are respectively 0.5 and 5 ppm. For each cavity the maximum loss budget due to the surface figure error should be smaller than 50 ppm. Moreover the transmission matching between the two inputs mirrors must be better than 99%. ududWe describe the different configurations that were explored in order to respect all these requirements. Coatings are done using IBS. ududThe two first configurations based on a single rotation motion combined or not with uniformity masks allow to obtain coating thickness uniformity around 0.2 % rms on 160 mm diameter. But this is not sufficient to meet all the specifications. ududA planetary motion completed by masking technique has been studied. With simulated values the loss cavity is below 20 ppm, better than the requirements. First experimental results obtained with the planetary system will be presented.
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机译：第二代重力波探测器的目标是将其灵敏度比现有的探测器（LIGO和VIRGO）提高一个数量级。这些检测器基于长基线迈克尔逊干涉仪，臂中具有高精细的Fabry-Perot腔，并且对反射镜质量有严格的要求。这些大型低损耗镜（直径340毫米，厚200毫米）必须具有接近完美的平坦度。涂层工艺不得在中心160 mm直径上添加大于二阶的表面图形Zernike项，且振幅> 0.5 nm。吸收和散射损耗的极限分别为0.5和5 ppm。对于每个腔，由于表面图形误差引起的最大损耗预算应小于50 ppm。此外，两个输入镜之间的透射匹配必须优于99％。 ud ud我们描述了为了满足所有这些要求而探索的不同配置。涂层使用IBS完成。 一种基于单个旋转运动的两种第一种配置，是否结合了均匀性掩模，都可以在160 mm直径上获得约0.2％rms的涂层厚度均匀性。但是，这还不足以满足所有规范。 ud ud研究了通过掩蔽技术完成的行星运动。通过模拟值，损耗腔低于20 ppm，优于要求。将介绍通过行星系统获得的第一批实验结果。
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