[FLASH-USERS] Laser Energy Depositing

[Hansen, Eddie]

This just sounds like the dependence of intensity on incident angle which should be proportional to cos^2(theta) (or sin^2(theta) depending on how you’re defining theta). So I can see a situation where the laser goes through the foils when it is exactly perpendicular to the foils if the laser power is very high. Then as you aim the laser to smaller angles (wrt the horizontal), the intensity goes down allowing the foils to absorb more. At some point (I guess 30-40 degrees as you observed), more of the laser is reflected than absorbed.

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Eddie Hansen
Research Scientist
Flash Center for Computational Science


From: flash-users <flash-users-bounces at flash.rochester.edu> on behalf of Kaldawi, Thomas <Tkal at lle.rochester.edu>
Date: Wednesday, July 12, 2023 at 2:55 PM
To: flash-users at flash.rochester.edu <flash-users at flash.rochester.edu>
Subject: [FLASH-USERS] Laser Energy Depositing
Hello,

I have two foils in the Laser Slab simulation (one at 30nm and the other at 0.5 microns), and the laser tends to go through the foils instead of reflecting/ablating them. I noticed that if I aim the laser at a small enough angle from the horizontal axis, the lasers will reflect off the foils as expected; however, at this current angle they just get absorbed into the foil which should not be happening. I do not know at what angle the lasers convert from relfecting to absorbing, but I would say it is around 30-40 degrees from the horizontal.

Does anyone have a solution to this? Maybe there is a setting in the laser energy that changes this?

Thank you,

Thomas Kaldawi
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