> A problem with mid-air ultrasound haptics is the weak displayed stimulation. As a solution to this, stimulation techniques as lateral modulation [21] and spatiotemporal modulation [22] have been proposed that increase the perceived intensity. Furthermore, recent studies have shown that not only vibratory sensations but also thermal sensations could be displayed. For example, in [23], a cold feeling is given remotely through the transport of cold air by the acoustic flow associated with a Bessel beam. In [24], a method for providing heat using the thermoacoustic phenomenon of ultrasonic waves passing through a narrow slit was demonstrated.

A contactless box that can faithfully simulate a wide array of tactile sensations sounds amazing.

[0] https://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=9392322