Mirror for performing metrology in laser beam system, laser beam system, EUV radiation source and lithographic apparatus

A mirror for performing metrology of a laser beam system in an EUV light source is provided, the mirror comprising:-a mirror layer having a front surface configured to receive and reflect a laser beam of the laser beam system; -a metrology layer arranged on the back surface of the mirror layer, the metrology layer comprising a resistive grid comprising a plurality of conductive segments and a plurality of electrical contacts, the plurality of electrical contacts being configured to be connected to a metrology instrument. 提供一种EUV光源中的激光束系统的用于执行量测的反射镜，该反射镜包括：-反射镜层，该反射镜层具有前表面，该前表面被配置为接收和反射激光束系统的激光束；-量测层，该量测层被布置在反射镜层的背表面上，该量测层包括电阻网格，该电阻网格包括多个导电段和多个电触点，该多个电触点被配置为连接到量测仪器。