Methods and systems for focusing and measuring by mean of an interferometer device, having an optical coherence tomography (OCT) focusing system, by separately directing an overlapped measurement and reference wavefront towards a focus sensor and towards an imaging sensor； where a predefined focusing illumination spectrum of the overlapped wavefront is directed towards the focus sensor, and where a predefined measurement illumination spectrum of the overlapped wavefront is directed towards the imaging sensor. Methods and systems for maintaining focus of an interferometer device, having an OCT focusing system, during sample's stage moves.本發明揭示用於憑藉具有一光學同調斷層攝影術(OCT)聚焦系統之一干涉儀裝置聚焦且量測之方法及系統，其係藉由分別引導一經重疊量測波前及參考波前朝向一聚焦感測器及朝向一成像感測器；其中引導該經重疊波前之一預定義聚焦照明光譜朝向該聚焦感測器，且其中引導該經重疊波前之一預定義量測照明光譜朝向該成像感測器。本發明揭示用於在樣品之載物台移動期間，維持具有一OCT聚焦系統之一干涉儀裝置之聚焦的方法及系統。
