Precision spectral sculpting for narrow-band amplification of broadband frequency-modulated pulses

摘要

Amplification of broadband frequency-modulated (FM) pulses in high-efficiency materials such as ytterbium-doped strontium fluorapatite results in significant gain narrowing, leading to reduced on-target bandwidths for beam smoothing and to conversion from frequency modulation to amplitude modulation (AM). To compensate for these effects, we have applied precision spectral sculpting, requiring both amplitude and phase shaping, to the amplification of broadband FM pulses in narrow-band gain media. We have demonstrated sculpting for centerline small-signal gains of 10~(4), producing amplified pulses that have both sufficient bandwidths for on-target beam smoothing and temporal profiles that have no potentially damaging AM.