Wavelength... Does It Matter If Power Is Equal For Scifi Directed Energy Weapons?

[Spacescifi]

Scenario: A scifi directed energy cannon is made for use on the battlefield.  Just small enough to fit inside the bed of a truck. Powerful enough to cut through an inch of steel every half second of sustained beaming.

Main Question: Choose your wavelength for maximum effectiveness on the battlefield.

You may choose radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, or gamma rays.
 

My pick: Microwaves. Good penetration and heating.

Versus Scenario: Assuming I had an armed ground force with twenty microwave cannons each as powerful as the OP (burns through an inch of steel every half second), would they have any advantage or disadvantage against an enemy force armed with directed energy cannons of the same power but using a wavelength other than microwaves?

 

Edited 5 hours ago by Spacescifi

[RCgothic]

Those powers are not equal because equal power will not produce equal cutting of steel at different wavelengths.

Gamma would probably pass through the 0.5in steel without significant heating. Radio would probably reflect harmlessly.

 

[magnemoe]

I say visible to UV laser works best, easy to produce and you can run it trough mirrors who don't work for x-rays and above so you can have one laser supporting multiple turrets, not relevant here but very nice on an plane. 
Still you are just moving an telescope not an gun turret you could even have extended masts 
As in atmosphere range is not very relevant and assume multiple MW so you cut an hole in the air and you don't want to go to low but if you could make an very efficient IR laser it would make sense.