Exploring the limits of broadband excitation and inversion: II. Rf-power optimized pulses

In [K. Kobzar, T.E. Skinner, N. Khaneja, S.J. Glaser, B. Luy, Exploring the limits of broadband excitation and inversion, J. Magn. Reson. 170 (2004) 236-243], optimal control theory was employed in a systematic Study to establish physical limits for the minimum rf-amplitudes required in broadband excitation and inversion Pulses. In a number of cases, however, experimental schemes are not limited by rf-amplitudes, but by the overall rf-power applied to a sample. We therefore conducted a second systematic study of excitation and inversion Pulses of varying Pulse durations with respect to bandwidth and rf-tolerances, but this time using modified algorithm involving restricted rf-power. The resulting pulses display a variety Of Pulse shapes with highly modulated rf-amplitudes and generally show better performance than corresponding Pulses With identical Pulse length and rf-power, but limited rf-amplitude. A detailed description of pulse shapes and their performance is given for the so-called power-BEBOP and power-BIBOP Pulses. (C) 2008 Elsevier Inc. All rights reserved.