论文标题
使用片上微腔内的高灵敏度空气耦合MHz频率超声检测
High sensitivity air-coupled MHz frequency ultrasound detection using on-chip microcavities
论文作者
论文摘要
由于它们的双呼声增强了灵敏度，腔体光学系统为超声传感提供了理想的平台。在这项工作中，我们根据窃窃图库模式的微腔，从Kilohertz（KHz）到Megahertz（MHz）频率范围高灵敏度超声传感。使用具有高光学Q因子（〜10^7）和机械Q因子（〜700）的57 UM直径的微型型，我们在0.25-3.2 MHz的频率范围内实现了46个UPA HZ^{ - 1/2} -1/2} -10 MPA Hz^{ - 1/2}的灵敏度。在2.56 MHz的机械共振周围实现了热噪声限制的灵敏度，频率范围为0.6 MHz。我们还观察到二阶和三阶机械边带，并定量研究每个机械边带的强度作为机械位移的函数。测量所有边带的信号与噪声比的组合具有扩展超声传感的动态范围的潜力。此外，为了提高KHz频率范围内的超声灵敏度，我们使用直径为200 um的微型风险，并在30 kHz-1.65 mHz范围内实现1.83 UPA HZ^{ - 1/2} -1/2} -1/2} -1/2} -1/2} -1/2} -1/2} -1/2}的敏感性。
Owing to their dual-resonance enhanced sensitivity, cavity optomechanical systems provide an ideal platform for ultrasound sensing. In this work, we realize high sensitivity air-coupled ultrasound sensing from kilohertz (kHz) to megahertz (MHz) frequency range based on whispering gallery mode microcavities. Using a 57 um-diameter microtoroid with high optical Q factor (~10^7) and mechanical Q factor (~700), we achieve sensitivities of 46 uPa Hz^{-1/2}-10 mPa Hz^{-1/2} in a frequency range of 0.25-3.2 MHz. Thermal-noise-limited sensitivity is realized around the mechanical resonance at 2.56 MHz, in a frequency range of 0.6 MHz. We also observe the second- and third-order mechanical sidebands, and quantitatively study the intensities of each mechanical sideband as a function of the mechanical displacement. Measuring the combination of signal to noise ratios at all sidebands has the potential to extend the dynamic range of ultrasound sensing. In addition, to improve the ultrasound sensitivity in the kHz frequency range, we use a microdisk with a diameter of 200 um, and achieve sensitivities of 1.83 uPa Hz^{-1/2}-10.4 mPa Hz^{-1/2} in 30 kHz-1.65 MHz range.
