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Diamond Radiator Thinning Using an Excimer Laser (view source)
Revision as of 16:36, 11 May 2010
, 16:36, 11 May 2010→Updates for April 2010
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*Knowing <math>\mathrm\omega_{0}</math> also allows us to calculate the theoretical fluence of the beam. Assuming maximum power of 220mJ over a 1.49mm x 0.552mm area yields <math>26J/cm^2.</math> Which is above the <math>14J/cm^2</math> threshold value cited by Brookhaven National Laboratories who were conducting diamond ablation experiments with a 213nm Nd:YAG laser (213nm with the use of a 4 + 1 frequency mixing crystal). Our ArF excimer laser produces 193nm light that will be more readily absorbed by the surface of the diamond as diamond is opaque to wavelengths above the band gap. These calculations provide a level of confidence that we theoretically will be able to ablate diamond.
*Knowing <math>\mathrm\omega_{0}</math> also allows us to calculate the theoretical fluence of the beam. Assuming maximum power of 220mJ over a 1.49mm x 0.552mm area yields <math>26J/cm^2.</math> Which is above the <math>14J/cm^2</math> threshold value cited by Brookhaven National Laboratories who were conducting diamond ablation experiments with a 213nm Nd:YAG laser (213nm with the use of a 4 + 1 frequency mixing crystal). Our ArF excimer laser produces 193nm light that will be more readily absorbed by the surface of the diamond as diamond is opaque to wavelengths above the band gap. These calculations provide a level of confidence that we theoretically will be able to ablate diamond.
==Updates for May 2010==
*An optics design has been made for focusing the 200mJ pulses from the excimer laser onto the diamond target. We are using a fused silica lens and a CaF2 entrance window. The entrance window will be adjusted at an angle to reduce the build-up of ablated material within the chamber as well as redirecting a small percentage of the beam for real-time power measurements. The photos below show the rail and the subsequent components.
{| cellpadding="3" style="text-align:center; margin: 1em auto 1em auto"
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| [[File:long_view_rail.jpg|right|thumb]] || || [[File:Brendan-optics.jpg|left|thumb]]|| ||[[File:Stage_lens_sensor.jpg|right|thumb]]
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{| cellpadding="3" style="text-align:center; margin: 1em auto 1em auto"
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| [[File:optics-laser.jpg|left|thumb]] || || [[File:optics_laser_scope.jpg|left|thumb]] || || [[File:Longview_oscilloscope.jpg|left|thumb]]
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*These photos are taken from a TurboCAD rendering of the optics rail that I completed this week. I have also added the 0.5cm x 0.5cm x 100 micron thick diamond at the optimum focal length ([http://zeus.phys.uconn.edu/wiki/index.php/Diamond_Radiator_Thinning_Using_an_Excimer_Laser#Updates_for_April_2010 17cm]) and tilted at a 45 degree angle from the beam axis. The blue cone represents the ablation plume and its dimensions are taken from plume characteristics observed in local thin film ablation laboratories.
{| cellpadding="3" style="text-align:center; margin: 1em auto 1em auto"
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| [[File:opticsE.jpg|right|thumb]] || || [[File:opticsC.jpg|left|thumb]]|| ||[[File:opticsD.jpg|right|thumb]]
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{| cellpadding="3" style="text-align:center; margin: 1em auto 1em auto"
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| [[File:optics.BlastTCW.jpg|left|thumb]] || || [[File:rail.jpg|left|thumb]] || || [[File:blastII.jpg|left|thumb]] || || [[File:diamond_blast.jpg|left|thumb]]
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