Fully Tunable Wavelengths: The Final Frontier?

If a single wavelength, tunable source of laser light with sufficient power could be used for materials processing, it would allow the user to dial in to an exact wavelength of light. This would excite only the preferred motions, which might be optimized for the process at hand whether it be welding, drilling, etc. Not only would you be able to excite a single motion to the exclusion of others, but you would also have higher efficiency because the wavelength chosen would have a higher percentage absorption.