Opt Lett. 2023 May 1;48(9):2313-2316. doi: 10.1364/OL.491457.
Feedback-based wavefront shaping is a promising and versatile technique for enhancing the contrast of a target signal for both coherent and incoherent light through a highly scattering medium. However, this technique can fail for a dynamic sample with a short correlation time. So far, most proposed methods for high-speed wavefront shaping can only directly enhance the intensity of coherent light but not incoherent light. Here we try to fill this gap to directly enhance incoherent light with high speed, such as fluorescence, which is essential in extending wavefront shaping to biomedical applications. For this purpose, we develop a technique based on a single acousto-optic deflector (AOD) with field-programmable gate array (FPGA) acceleration for spatiotemporal focusing within milliseconds. With the digital time gating of the feedback signal, spatiotemporal focusing of laser light with high contrast can be formed behind dynamic scattering media in milliseconds resulting in fluorescence enhancement. Furthermore, FPGA-based wavefront shaping is shown to effectively enhance fluorescence directly behind dynamic samples with short correlation times.
基于反馈的波前整形是一种很有前途和多功能的技术，可以通过高度散射的介质增强相干和非相干光的目标信号对比度。然而，对于相关时间短的动态样本，这种技术可能会失败。到目前为止，大多数用于高速波前整形的方法只能直接增强相干光的强度，而不能增强非相干光的强度。在这里，我们试图填补这一空白，以高速直接增强非相干光，如荧光，这对于将波前整形扩展到生物医学应用至关重要。为此，我们开发了一种基于单个声光偏转器（AOD）和现场可编程门阵列（FPGA）加速的技术，用于在毫秒内实现时空聚焦。通过反馈信号的数字时间选通，可以在动态散射介质后毫秒级形成对比度高的激光时空聚焦，从而实现荧光增强。此外，基于 FPGA 的波前整形被证明可以有效地增强短相关时间动态样本后的荧光。
