Changes

[[Image:GP2000b.png|left|thumb|250px| Figure: Average laser output as a function of total shots fired.]]  

[[Image:GP2000b.png|left|thumb|250px| Figure: Average laser output as a function of total shots fired.]]  

An average cut depth of 38µm per complete pass would estimate a total of over 2.6 million pulses to reach the final depth of 20 µm or roughly 7 complete laser medium fills. The ablation setup has methods to compensate for fluctuations in average laser energy so that the diamond surface remains smooth to within ± 0.5µm (these methods will be discussed in detail in a later section). However, even with these corrections, allowing the average laser energy to vary by 50% over the course of a single pass results in non-uniform ablation across the diamond which is too exaggerated to compensate for. It is then desirable to extend the lifetime of the laser gas medium so that average power remains constant over a single pass. Ideally, the laser would have a gas life time which exceeds the total number of pulses required to bring the diamond sample to 20µm. An Oxford GP-2000 cryogenic gas purification system and Millipore particulate filter were installed in a closed loop with the laser cavity as shown in Figure 1. The system pumps the laser gas medium through a liquid nitrogen cold trap removing contaminants generated during the lasing process, extending the laser gas life time by over an order of magnitude. The plot below shows the average pulse energy as a function of pulses completed. Figure 3 shows the comparison between running the laser with (blue) and without (red) the gas purification system. Using the gas purifier in line with the laser cavity resulted in an order of magnitude increase in number of total pulses fired. Also, the average output energy of the laser increased significantly due to filtration of halogen spoiling contaminants inside the laser cavity. In some cases only a single fill was required to ablate a diamond from start to finish-greatly reducing the surface variation on the diamond radiator and the cost of running the machine. It is conclusive to say that without the use of the gas purification system this laser would not be viable for use as a light source for diamond ablation purposes.

An average cut depth of 38µm per complete pass would estimate a total of over 2.6 million pulses to reach the final depth of 20 µm or roughly 7 complete laser medium fills. The ablation setup has methods to compensate for fluctuations in average laser energy so that the diamond surface remains smooth to within ± 0.5µm (these methods will be discussed in detail in a later section). However, even with these corrections, allowing the average laser energy to vary by 50% over the course of a single pass results in non-uniform ablation across the diamond which is too exaggerated to compensate for. It is then desirable to extend the lifetime of the laser gas medium so that average power remains constant over a single pass. Ideally, the laser would have a gas life time which exceeds the total number of pulses required to bring the diamond sample to 20µm. An Oxford GP-2000 cryogenic gas purification system and Millipore particulate filter were installed in a closed loop with the laser cavity as shown in Figure 1. The system pumps the laser gas medium through a liquid nitrogen cold trap removing contaminants generated during the lasing process, extending the laser gas life time by over an order of magnitude. The plot below shows the average pulse energy as a function of pulses completed. Figure 3 shows the comparison between running the laser with (blue) and without (red) the gas purification system. Using the gas purifier in line with the laser cavity resulted in an order of magnitude increase in number of total pulses fired. Also, the average output energy of the laser increased significantly due to filtration of halogen spoiling contaminants inside the laser cavity. In some cases only a single fill was required to ablate a diamond from start to finish-greatly reducing the surface variation on the diamond radiator and the cost of running the machine. It is conclusive to say that without the use of the gas purification system this laser would not be viable for use as a light source for diamond ablation purposes.

==Laser Beamline==

==Laser Beamline==