Fourier domain diffuse correlation spectroscopy with heterodyne holographic detection.
Fourier domain diffuse correlation spectroscopy with heterodyne holographic detection.
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DOI：
10.1364/boe.400525
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发表时间：
2020-11-01
影响因子：
3.4
通讯作者：
Powell S
中科院分区：
文献类型：
--
作者：
James E;Powell S
我们提出了一种新的漫相关光谱方法，克服了单模光子计数技术的有限光通量。我们的系统采用外差全息检测，允许使用传统的 sCMOS 相机在散粒噪声极限下并行测量数千种模式的波动电场的功率谱。与传统技术相比，这使得检测器成本降低了一个数量级，同时还提供了对环境光影响的稳健性以及体外实验期间改进的信噪比。我们展示了一个 GPU 加速的全息解调系统，能够实时处理输入数据（每秒 7940 万像素），以及一种新颖的漫相关光谱傅里叶域模型，可以从测量的数据中直接恢复流参数。我们的检测和建模策略通过调制光学组织模型的布朗分量得到严格验证，证明布朗扩散系数的绝对测量与传统方法非常一致。我们通过对人体前臂测量的脉动流速进行体内测量，进一步证明了我们系统的可行性。
We present a new approach to diffuse correlation spectroscopy which overcomes the limited light throughput of single-mode photon counting techniques. Our system employs heterodyne holographic detection to allow parallel measurement of the power spectrum of a fluctuating electric field across thousands of modes, at the shot noise limit, using a conventional sCMOS camera. This yields an order of magnitude reduction in detector cost compared to conventional techniques, whilst also providing robustness to the effects of ambient light and an improved signal-to-noise ratio during in vitro experiments. We demonstrate a GPU-accelerated holographic demodulation system capable of processing the incoming data (79.4 M pixels per second) in real-time, and a novel Fourier domain model of diffuse correlation spectroscopy which permits the direct recovery of flow parameters from the measured data. Our detection and modelling strategy are rigorously validated by modulating the Brownian component of an optical tissue phantom, demonstrating absolute measurements of the Brownian diffusion coefficient in excellent agreement with conventional methods. We further demonstrate the feasibility of our system through in vivo measurement of pulsatile flow rates measured in the human forearm.