Inverse Laplace transform of the function: $F(s)=e^{-a\sqrt{s(s+b)}}$

I would like to find inverse Laplace transform of the function: $$F(s)=e^{-a\sqrt{s(s+b)}}$$ which $a$ and $b$ are positive real numbers and $s$ is a complex variable. It would be appreciated if someone can help me.

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