The task is to create plasma of temperature -40C to +150C maximum, this plasma could be created from gas such as Argon...ionizing this gas to make plasma would be ideal, could high powered laser be used to ionize the gas?

An ionized gas has free electrons. They must be moving at a high speed relative to the ions or else they wouldn't be free. Such a mixture wouldn't be below 150C.

An ionized gas has free electrons. They must be moving at a high speed relative to the ions or else they wouldn't be free. Such a mixture wouldn't be below 150C.

yet cold plasma exists...

The lower the Z, the lower the binding energy of the electrons. Try H or He and see what temperature the binding energy would equate to.