System and method for pumping laser sustained plasma with an illumination source having modified pupil power distribution

A system for generating broadband illumination, comprising:

• a plasma forming material;
• one or more pump modules, each pump module including:
• an illumination source configured to output illumination having a first beam profile with a central peak and decreasing intensity along a transverse direction perpendicular to a propagation direction;
• a focusing lens;
• and
• a beam shaper configured to receive the illumination having the first beam profile from the illumination source and configured to output pump illumination having a second beam profile that is different from the first beam profile, wherein the second beam profile is selected to provide a distribution of the output pump illumination through a focal region around a focal plane when focused with the focusing lens, wherein the distribution of the output pump illumination maintains a plasma in at least a portion of the focal region around the focal plane when focused with the focusing lens, wherein the plasma emits broadband light, wherein the second beam profile and a power of the output pump illumination are selected to increase at least one of a radiance or a temperature of the plasma relative to a plasma generated with the first beam profile by decreasing a peak intensity of the output pump illumination in locations prior to the focal plane to decrease a length of the plasma along the propagation direction in the locations prior to the focal plane, decrease associated absorption of the output pump illumination by the plasma in the locations prior to the focal plane, and increase absorption of the output pump illumination by the plasma in locations proximate to the focal plane relative to the plasma generated with the first beam profile.

A method of generating broadband illumination, comprising:

• generating illumination having a first beam profile with an illumination source, wherein the first beam profile includes a central peak and decreasing intensity along a transverse direction perpendicular to a propagation direction;
• reshaping the illumination having the first beam profile into pump illumination having a second beam profile that is different from the first beam profile;
• and
• directing the pump illumination to a plasma forming material, wherein the second beam profile is selected to provide a distribution of the output pump illumination through a focal region around a focal plane when focused with a focusing lens, wherein the distribution maintains a plasma in at least a portion of the focal region around the focal plane when focused with the focusing lens, wherein the plasma emits broadband light, wherein the second beam profile and a power of the output pump illumination are selected to increase at least one of a radiance or a temperature of the plasma relative to a plasma generated with the first beam profile by decreasing a peak intensity of the output pump illumination in the locations prior to focal plane to decrease a length of the plasma along the propagation direction in the locations prior to the focal plane, decrease associated absorption of the output pump illumination by the plasma in the locations prior to the focal plane, and increase absorption of the output pump illumination by the plasma in locations proximate to the focal plane relative to the plasma generated with the first beam profile.

A system for generating pump illumination for a laser sustained plasma, comprising:

• an illumination source configured to output illumination having a first beam profile with a central peak and decreasing intensity along a transverse direction perpendicular to a propagation direction;
• a focusing lens;
• and
• a beam shaper configured to receive the illumination having the first beam profile from the illumination source and configured to output pump illumination having a second beam profile that is different from the first beam profile, wherein the second beam profile is an inverted profile having a center-to-edge ratio of less than one, is selected to provide a distribution of the output pump illumination through a focal region around the focal plane when focused with the focusing lens, wherein the through-focus distribution maintains a plasma in at least a portion of the focal region around the focal plane when focused with the focusing lens, wherein the plasma emits broadband light, wherein the second beam profile and a power of the output pump illumination are selected to increase at least one of a radiance or a temperature of the plasma relative to a plasma generated with the first beam profile by decreasing a peak intensity of the output pump illumination in locations prior to the focal plane in order to decrease a length of the plasma along the propagation direction in the locations prior to the focal plane, decrease associated absorption of the output pump illumination by the plasma in the locations prior to the focal plane, and increase absorption of the output pump illumination by the plasma in locations proximate to the focal plane relative to the plasma generated with the first beam profile.