Maybe this can help to understand the principles: 

for ablation and penetration depth:

http://www.faculty.virginia.edu/CompMat/Ablation.html

or

JOURNAL OF LASER APPLICATIONS VOLUME 19, NUMBER 3 AUGUST 2007

"Estimating spot size and relating hole diameters with fluence and number

of shots for nanosecond and femtosecond laser ablation of

polyethylene terephthalate"

for beam determination:

http://www.newport.com/Gaussian-Beam-Optics/144899/1033/content.aspx

https://en.wikipedia.org/wiki/Radiant_exposure

hope it helps :)

Thank you very much! thank you!

Fluence can be calculated by measuring energy of the source by energy meter and dividing it by spot size (which you can easily measured by Knife edge experiment).

Here penetration depth seems to be Rayleigh range, which can be calculated by simple nonlinear optics technique (refer Sheikh bhae et. al)