Cognitive response to energy variations in Non-Contact tactile sensations interface using Laser-Induced plasma

Laser-induced plasma technology provides a novel method for generating tactile sensations without physical contact, offering precise and controlled stimulation. However, the impact of varying energy levels on human cognitive and perceptual responses is not yet fully understood. This study aimed to present tactile sensations using laser-induced plasma in a non-contact manner and investigate the cognitive characteristics linked to changes in the plasma's energy parameters, specifically Pulse Width (PW) and Set Current (SC). The experiment was conducted with 35 right-handed male and female adults in their 20 s. Tactile stimuli were presented under two conditions: Condition 1 fixed SC and varied PW, while Condition 2 fixed PW and varied SC, with each condition adjusted to produce three energy levels. Subjective evaluations included assessments of tactile intensity and vocabulary using a 5-point scale. Sixteen terms related to tactile sensations were evaluated. A two-way repeated measures analysis of variance was used to compare scores across both factors (Condition and Energy). The results showed that as the energy level increased, the perceived intensity also rose. In the vocabulary evaluation, sensations such as "Tapping" and "Rapping" were predominant, with higher scores at increased energy levels. No significant differences were observed between the two conditions for either tactile intensity or vocabulary evaluations. In conclusion, varying the energy magnitude of laser-induced plasma can produce tactile sensations of different intensities, and the parameters used in this study successfully evoked specific sensations like slow vibration.