The light needs to scatter off a surface or a gaseous mist so that the light appears to emanate from a particular location. Just as you can't see a laser beam propagate in free space unless there is a scattering medium or you are actually looking into the beam, which is not recommended for higher powers exceeding eye damage thresholds. A scattering medium is required in free space to enable visibility to an arbitrarily located observer. There will likely be variation in the brightness of the hologram depending on whether the light is more forward scattered or more highly backscattered.
@Eric_hubner sir, it thought this .. but i have to make those gas particles in the shape of the original hologram . Sir tell me two more things , if we intersect 2 laser beams will it make a glowing point at intersection ? And can we do it with intersecting laser beams and form a image due to interference?
Unless you are transmitting through a nonlinear medium, there won't be any interference between the two laser beams traveling through free space. The beams can pass through each other without scattering interaction. You may be able to play back an H2 hologram into a mist though via Conference Paper An updated diorama with a full-color H2 analog hologram