Amplitude and frequency/phase modulated pulses to achieve plane rotations of nuclear spin magnetization vectors with inhomogeneous B1 fields

摘要

Two amplitude/frequency/phase modulated pulses that can achieve 90 DEG plane rotations over large B1 field inhomogeneities are described. The pulses achieve this by use of a "flip" in the direction of the effective B1 field half-way through the pulse, and by use of a discontinuous phase jump in addition to continuous frequency of phase modulation. These pulse can be used for rotation of magnetization vectors between any plane that is perpendicular to the transverse plane and the transverse plane of the rotating reference frame. Consequently, then can be used for interchanging amplitude and phase information and converting amplitude modulated rotating frame experiments into phase modulated experiments.