Diffractive optical elements for transformation of modes in lasers

An apparatus, comprising:

• a HOM ribbon fiber amplifier configured to receive and amplify a higher order mode (HOM) input beam to produce an amplified HOM beam;
• a first diffractive optical element (DOE) configured to impart a predetermined phase onto said amplified HOM beam to produce an amplified fundamental mode beam;
• and
• a second DOE configured to transform the phase of said amplified fundamental mode beam into a single fundamental mode beam.

A method, comprising:

• providing an apparatus comprising:
• a first diffractive optical element (DOE) configured to transform the phase of an input beam so that a plurality of output beams having a predetermined intensity distribution is generated;
• and
• a second DOE configured to impart a predetermined phase onto said plurality of output beams to produce a higher order mode (HOM) output beam that comprises said predetermined intensity distributions and said predetermined phase;
• directing an input beam onto said first DOE to produce said plurality of output beams having said predetermined intensity distribution;
• and
• directing said plurality of output beams onto said second DOE to produce said higher order mode (HOM) output beam that comprises said predetermined intensity distributions and said predetermined phase.

A method, comprising:

• providing an apparatus comprising:
• a HOM ribbon fiber amplifier configured to receive and amplify a higher order mode (HOM) input beam to produce an amplified HOM beam;
• a first diffractive optical element (DOE) configured to impart a predetermined phase onto said amplified HOM beam to produce an amplified fundamental mode (TEM00) amplitude profile;
• and
• a second DOE configured to transform the phase of said amplified amplitude profile into a single fundamental mode (TEM00) beam;
• directing said higher order mode (HOM) input beam into said HOM ribbon fiber amplifier to produce said amplified HOM beam;
• directing said amplified HOM beam onto said first DOE to produce said amplified fundamental mode (TEM00) amplitude profile;
• and
• directing said amplified fundamental mode beam onto said second DOE to produce said single fundamental mode (TEM00) beam.