Every laser has what is termed a coherence length.
It is related to the length of the laser tube and the purity of the phase of light emitted and the wavelength itself. The more pure the light the greater the coherence length. That is, not just any kind of laser can be used in making a hologram. This means that the laser is operating in the lowest transverse mode, which is the most uniform across the beam and is preferred for holography. A laser inteded for making holograms must ideally be lasing in just one longitudinal mode.