Question on a thermal lens

I have encountered a problem.
I put a silicon glass slab exposed under a Gauss beam. Air cooling is added.

For the first step I used RF to see how the light transmitting through the slab, which is working quite well.

For the second step I figured out how the air flows works, which I can still see a good result.

For the third step I want to find how much is the temperature under such a cooling air and such power of optical field. But no matter how large the Gauss beam power is, or no matter how large the imaginary part of the glass refractive index is, the glass slab seems to have no tempareture rising. I don't know where I made the mistake or what physical conditions should be added on. Please some one see this program for me?

Thanks ahead.

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Just a beginner.