I've thought the better idea would be to tune the laser beam to resonantly scatter off certain ions that are kept trapped in a magnetic field.
Singly ionized alkaline earth elements (magnesium, calcium) should have very strong resonant absorption, just like neutral sodium, due to the single outer shell electron. If the laser is tuned properly it could even cool the ions, preferentially scattering off ions moving toward the laser beam, reducing their kinetic energy in the rest frame of the vehicle.
The idea of laser cooling might also apply to a solid laser sail.
Singly ionized alkaline earth elements (magnesium, calcium) should have very strong resonant absorption, just like neutral sodium, due to the single outer shell electron. If the laser is tuned properly it could even cool the ions, preferentially scattering off ions moving toward the laser beam, reducing their kinetic energy in the rest frame of the vehicle.
The idea of laser cooling might also apply to a solid laser sail.