Finger distance perception plays a crucial role in enabling humanoid intelligent robotic systems to achieve smooth interaction with humans. Here, a rapidly response optical humidity sensor enabled with graphene quantum dots (GQD) for non-contact finger distance detection was proposed. The GQD was prepared through the functionalization of graphene oxide (GO) with hydrophilic groups. This modification enhances the responsiveness of GO to atmospheric humidity and promotes the deposition of conformal films of functional materials on the surfaces of optical fiber. Utilizing a light-driven coating method, the GQD was deposited onto a tilted fiber Bragg grating (TFBG) to fabricate humidity sensor. When water molecules were absorbed by GQD, the dielectric constant of GQD film was changed, causing an alteration in the intensities of the TFBG’s cladding modes. The proposed sensor shows a sensitivity of 0.032 dB/%RH with the equilibrium response and recovery time of 3.66 s and 0.92 s, respectively. The equilibrium recovery time is the fastest as far as we know. Furthermore, the sensor is capable of precisely identifying the action of a finger, such as approaching, remaining, and departing with a detection range of 0–10 mm.

中文翻译：

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通过 GQD 实现高恢复速度光学湿度传感，可实现非接触式手指距离检测


手指距离感知对于仿人智能机器人系统实现与人类的顺畅交互起着至关重要的作用。这里，提出了一种采用石墨烯量子点（GQD）的快速响应光学湿度传感器，用于非接触式手指距离检测。 GQD是通过用亲水基团对氧化石墨烯（GO）进行官能化而制备的。这种修饰增强了GO对大气湿度的响应能力，并促进了功能材料保形薄膜在光纤表面的沉积。利用光驱动涂层方法，将 GQD 沉积到倾斜光纤布拉格光栅 (TFBG) 上以制造湿度传感器。当水分子被 GQD 吸收时，GQD 薄膜的介电常数发生变化，导致 TFBG 包层模式的强度发生变化。所提出的传感器的灵敏度为 0.032 dB/%RH，平衡响应和恢复时间分别为 3.66 s 和 0.92 s。据我们所知，平衡恢复时间是最快的。此外，传感器能够精确识别手指的接近、停留、离开等动作，检测范围为0-10毫米。