A method for laser processing a transparent workpiece includes forming a contour line in the transparent workpiece and directing an infrared laser beam output by an infrared beam source through an a focal beam adjustment assembly and onto the transparent workpiece along the contour line to separate the transparent workpiece along the contour line. The infrared laser beam forms an annular infrared beam spot on a surface of the transparent workpiece. The infrared laser beam includes an entrance beam diameter upstream the afocal beam adjustment assembly and an exit beam diameter downstream the afocal beam adjustment assembly. The annular infrared beam spot includes an inner diameter, an outer diameter, and an annular thickness. Further, the focal beam adjustment assembly includes one or more adjustable optical elements. Moreover, adjusting the one or more adjustable optical elements alters the exit beam diameter, thereby altering the annular thickness of the annular infrared beam spot.