A system for forming a plurality of defects defining a contour in a workpiece, said workpiece comprising a glass substrate (1; 1400) comprising at least one layer and having a normalized pre-defect formation fracture toughness rating of 1.0, the system comprising: a laser assembly (3; 1505) configured to provide a plurality of laser pulse emissions, each laser pulse emission of the plurality of laser pulse emissions having predetermined characteristics selected from the group consisting of wavelength, power level, pulse duration, and a laser pulse emission rate; an optical assembly (6; 1505) coupled to the laser assembly (3; 1505), the optical assembly (6; 1505) being configured and moveable to focus each laser pulse emission to a different focal line at a different position within said workpiece, wherein: each said different focal line is separated from an adjacent different focal line by a predetermined distance, a corresponding defect with an average crack length is formed in said workpiece along each different focal line to form a plurality of defects defining a contour in said workpiece, and each of said defects being substantially generated by induced absorption; a workpiece holder configured to hold said workpiece at a position relative to the optical assembly (6; 1505), said workpiece holder or the optical assembly (6; 1505) being configured to provide a relative motion between said workpiece and the optical assembly (6; 1505); and a controller coupled to the laser assembly (3; 1505), the optical assembly (6; 1505) or said workpiece holder, the controller being configured to execute instructions representing a predetermined design, the controller being configured to select the predetermined characteristics, the different positions, the predetermined distances, the average crack lengths, or the relative motion such that a ratio of an average of the predetermined distances to an average of the averaged crack lengths results in said workpiece having a post-defect formation fracture toughness rating along the contour of less than the normalized pre-defect formation fracture toughness rating. a laser assembly (3; 1505) configured to provide a plurality of laser pulse emissions, each laser pulse emission of the plurality of laser pulse emissions having predetermined characteristics selected from the group consisting of wavelength, power level, pulse duration, and a laser pulse emission rate; an optical assembly (6; 1505) coupled to the laser assembly (3; 1505), the optical assembly (6; 1505) being configured and moveable to focus each laser pulse emission to a different focal line at a different position within said workpiece, wherein: each said different focal line is separated from an adjacent different focal line by a predetermined distance, a corresponding defect with an average crack length is formed in said workpiece along each different focal line to form a plurality of defects defining a contour in said workpiece, and each of said defects being substantially generated by induced absorption; each said different focal line is separated from an adjacent different focal line by a predetermined distance, a corresponding defect with an average crack length is formed in said workpiece along each different focal line to form a plurality of defects defining a contour in said workpiece, and each of said defects being substantially generated by induced absorption; a workpiece holder configured to hold said workpiece at a position relative to the optical assembly (6; 1505), said workpiece holder or the optical assembly (6; 1505) being configured to provide a relative motion between said workpiece and the optical assembly (6; 1505); and a controller coupled to the laser assembly (3; 1505), the optical assembly (6; 1505) or said workpiece holder, the controller being configured to execute instructions representing a predetermined design, the controller being configured to select the predetermined characteristics, the different positions, the predetermined distances, the average crack lengths, or the relative motion such that a ratio of an average of the predetermined distances to an average of the averaged crack lengths results in said workpiece having a post-defect formation fracture toughness rating along the contour of less than the normalized pre-defect formation fracture toughness rating.