The Two Photon Absorption – Transient Current Technique (TPA-TCT) uses fs-pulsed infrared lasers, with photon energies below the silicon band gap. Excess charge carriers are generated mainly in a small volume (approximately 1µm × 1µm × 20µm) around the focal point of the laser beam, enabling a resolution in all three spatial directions. Compared to conventional Single Photon Absorption – TCT, the resolution perpendicular to the incident laser beam is typically increased by a factor of ten. Following the initial success of the method, a compact TPA-TCT setup was developed at CERN. The TPA-TCT setup and various measurements with the focus on the charge collection and the gain suppression in LGAD sensors will be presented.