A charged particle beam apparatus includes a charged particle source configured to generate charged particles, an electrode configured to accelerate the charged particles to form a charged particle beam, a bender unit configured to adjust a path of the charged particle beam, and an objective lens configured to focus the charged particle beam onto a spot on a sample. The charged particle beam passes through a bore of the objective lens as the charged particle beam propagates from the charged particle source to the sample. The apparatus also includes a light source configured to generate a light beam, and a mirror disposed within the bender unit and arranged to direct the light beam to the spot on the sample.