We describe a means of communication in which a user with no external receiver hears an audible audio message directed only at him/her. A laser transmits the message, which is encoded upon a modulated laser beam and sent directly to the receiver’s ear via the photoacoustic effect. A 1.9 μm thulium laser matched to an atmospheric water vapor absorption line is chosen to maximize sound pressure while maintaining eye-safe power densities. We examine the photoacoustic transfer function describing this generation of audible sound and the important operational parameters, such as laser spot size, and their impact on a working system.

中文翻译：

---

光声通信：通过大气H ₂ O吸收光来传递可听信号

我们描述了一种通信方式，其中没有外部接收器的用户听到仅针对他/她的可听音频消息。激光发射该消息，该消息在调制的激光束上编码，并通过光声效应直接发送到接收者的耳朵。选择了与大气中的水蒸气吸收线匹配的1.9μmlaser激光器，以在保持人眼安全的功率密度的同时最大化声压。我们检查了光声传递函数，该函数描述了这种可听见的声音的产生以及重要的操作参数，例如激光光斑的大小及其对工作系统的影响。