As shown in the figure above the ablation chamber is mounted on two orthogonal translation stages, both with bidirectional repeatability of <1.5 µm and minimum achievable incremental movement of 0.05 µm/. The x-stage moves the diamond in the horizontal plane with respect to the lab floor. The y-stage increments at a 45◦ angle to the lab floor which is in the same plane as the diamond. Digital dial indicators with sub-micron resolution were installed to measure the positions of the x and y translation stage and were used in a study to measure the non-linearity of the y-translation stage motor. Non-linearity (movement in the lead-screw of the translation stage which does not place the stage at the requested position) of the y-stage is critical due to the row-by-row rastering sequence used to deferentially ablate the diamond sample. Each row has a unique sequence of laser pulses that correspond to an exact position on the diamond and the control of the ablation rate relies on the overlap between these rows. The dial indicator shown in Figure 16 is placed at a 45◦ angle and makes contact with an aluminum extension mounted to the y-stage. The dial indicator has a rolling bearing attached to its end so that it rides along the extension as the x-translation stage moves back and forth. The ablation chamber was moved to a series of y coordinates and the difference between the desired displacement and the displacement measured by the dial indicator was taken and is shown in Figure 17a. | As shown in the figure above the ablation chamber is mounted on two orthogonal translation stages, both with bidirectional repeatability of <1.5 µm and minimum achievable incremental movement of 0.05 µm/. The x-stage moves the diamond in the horizontal plane with respect to the lab floor. The y-stage increments at a 45◦ angle to the lab floor which is in the same plane as the diamond. Digital dial indicators with sub-micron resolution were installed to measure the positions of the x and y translation stage and were used in a study to measure the non-linearity of the y-translation stage motor. Non-linearity (movement in the lead-screw of the translation stage which does not place the stage at the requested position) of the y-stage is critical due to the row-by-row rastering sequence used to deferentially ablate the diamond sample. Each row has a unique sequence of laser pulses that correspond to an exact position on the diamond and the control of the ablation rate relies on the overlap between these rows. The dial indicator shown in Figure 16 is placed at a 45◦ angle and makes contact with an aluminum extension mounted to the y-stage. The dial indicator has a rolling bearing attached to its end so that it rides along the extension as the x-translation stage moves back and forth. The ablation chamber was moved to a series of y coordinates and the difference between the desired displacement and the displacement measured by the dial indicator was taken and is shown in Figure 17a. |