Zecotek Laser Systems Inc. | Date: 2010-09-13
Output beam from laser diode bar (1) has divergence around 40 degrees along the fast axis and around 12 degrees along the slow one. The quality of such a beam along the fast axis is good and fast axis collimating lens (FAC) (2) can compensate its high divergence down to 0.5-1 degrees. In the direction of the slow axis the beam from the laser diode bar is focused by cylindrical lens (3) onto the pumping face of laser active medium (5). The pumping face is wider than the pumping spot on it to ensure efficient collection of pumping light. Laser active medium has two parallel faces which form a waveguide for the pumping light. As a result, the pumping light is confined within the waveguide along the slow-axis direction and collimated (near parallel) in the fast-axis direction. Therefore, length of the pump volume (6) can be as long as the laser element itself.