It's not a hologram, of course. It's a stack of flat displays.
That's been tried before, in many ways. The first try was a vibrating mirror.[1] There's a flat rotating mirror system from FakeSpace.[2] It's not bad; you can walk around it. Move vertically, though, and the illusion breaks down. There's a scheme with gas ionized by intersecting laser beams. That's very low-rez, but truly volumetric.
Eventually, someone may come up with a real hologram system with decent resolution. A research group at MIT built one, but it was very low resolution and single-color. It's not impossible. But this isn't it.