A Z-axis focusing mechanism having a scanner and a prism whose front and rear faces are not normal to the direction of travel of a light beam prior to the light beam impinging upon the front face of the scanner. The scanner and the prism are oriented with respect to one another such that when a light beam is scanned onto the front face of the prism, a scanned beam having varying Z-axis focus points at distinct lateral locations exits the rear face of the scanner. Alternatively, the rear face of the prism may be normal to the light beam as it passes through the prism, which generates a retro-reflected, scanned light beam that exits the front of the prism.