Cited on HN 5 times, 2015–2024, never outright recommendedscore 0
Years with an HN recommendation, 2007–2026
Linked as the demo behind femtosecond plasma displays, often noting the touch burns skin and the system is loud.
A SIGGRAPH demo from Yoichi Ochiai's group of aerial and volumetric graphics drawn by focused femtosecond lasers with computational holography. The plasma points can be touched.
“Here's the YouTube link with the demo” (HN, 2015)
An example of "tangible interaction" is pressing this checkbox in this video: [this video] In terms of what the projection feels like, this article explains that to some people the laser feels like sandpaper, and to some people it feels like a static shock: [link]
Using the term thin air is misleading IMO. I saw a slightly different version of this a few years ago [1]. It basically used pulsed laser to create plasma at certain x,y,z without any additional reflective medium added to the environment. However it's crazy loud [2]. From the Nature paper [3] it seems to work on similar principles with the drawback that you need "light scattering (or absorbing and generating) surfaces" instead of free air. In other words you still need some medium for projection/reflection, like a smoke cloud for example: "it is unlikely that the display would function outdoors without an enclosure unless particles were much more strongly confined or steps were taken to refresh trapped particles regularly" [1] [this video] [2] [link] [3] [link]
Similar laser plasma display needing no medium but very loud
This page has been around for a while. If you watch the YouTube video, you can see the skin on the person’s finger get burnt as they touch the little tiny plasma balls. [this video]
Demo showing skin burning on touching plasma points
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