  Long-lived (symmetry protected) hyperpolarized spin states offer important
new opportunities (for example, in clinical MR imaging), but existing methods
for producing these states are limited by either excess energy dissipation or
high sensitivity to inhomogeneities. We extend recent work on continuous-wave
irradiation of nearly-equivalent spins (spin-lock induced crossing) by
designing composite pulse and adiabatic shaped-pulse excitations which overcome
the limitations. These composite and adiabatic pulses differ drastically from
the traditional solutions in two-level systems. We also show this works in
chemically equivalent spin pairs, which has the advantage of allowing for
polarization transfer from and to remote spins. The approach is broadly
applicable to systems where varying excitation strength induces an avoided
crossing to a dark state, and thus to many other spectroscopic regimes.
