PHOTON TUNNELING: SHEDDING NEW LIGHT ON BIOMEDICINE

描述 摘要： 大多数幼儿对世界的了解有80%到90%来自于视觉。当我们试图了解我们自己身体的内部运作时，情况就不同了，因为光在“皮肤深处“由于多重散射而变得漫射。相反，研究人员已经求助于替代手段，如X射线，磁共振和超声波，以探测身体深处。到目前为止，光学成像的大多数进展都是面向散射组织中深度小于1 mm的高分辨率功能和分子成像。自生物医学光学诞生以来，对高空间分辨率的深层组织光学成像的追求一直受到固有光扩散的阻碍。我们必须迎接这一挑战，以充分发挥光的潜力，因为从物理和生物学的角度来看，光是一种强大的工具。在物理上，光覆盖的电磁频谱的一小部分是直接探测分子结构的唯一部分;在生物学上，分子感知、反应和发光的能力是在最基本的基础上编码的（即，基因）水平！此外，作为非电离辐射的光对生物有机体来说就像空气和水一样安全。因此，只要我们能克服光的扩散这一看似牢不可破的障碍，光就成为可视化生物结构和事件、询问和控制生物过程以及诊断和治疗疾病的最自然的选择。虽然光的多重散射在传统智慧中被视为一个问题，但我认为它应该是解决方案的一部分。我们最近关于时间反转超声编码（TRUE）光学聚焦的工作（Nature Photonics 2011）是该方向的首次突破。真正的聚焦可以无创地将光传递到散射介质深处的动态定义的焦点。这项发明为更大的范式转变打开了大门。

DESCRIPTION Abstract: Eighty to ninety percent of what most young children learn about the world comes through vision. The same cannot be said when we seek to learn about the inner workings of our own body, because light beyond ""skin deep"" becomes diffused due to multiple scattering. Instead, researchers have resorted to alternative means-such as X-ray, magnetic resonance, and ultrasound-to probe deep into the body. Until now, most advances in optical imaging have been geared towards high-resolution functional and molecular imaging at depths less than 1 mm in scattering tissue. The pursuit of deep-tissue optical imaging with high spatial resolution has been stymied by the inherent optical diffusion-the grand challenge since the inception of biomedical optics. We must meet this challenge to reach the full potential of light because it is such a powerful tool from both the physical and biological perspectives. Physically, the tiny fraction of the electromagnetic spectrum that light covers is the only part that probes molecular structures directly; biologically, the ability of molecules to sense, react to, and emit light is encoded on the most fundamental (i.e., genetic) level! In addition, light as nonionizing radiation is as safe to biological organisms as air and water. Therefore, light is the most natural choice fo visualizing biological structures and events, interrogating and controlling biological processes, as well as diagnosing and treating diseases, if only we could overcome the optical diffusion-a seemingly unbreakable barrier. While multiple scattering of light is treated as a problem in conventional wisdom, I believe that it should be part of the solution. Our recent work on time-reversed ultrasonically encoded (TRUE) optical focusing (Nature Photonics 2011) is a first breakthrough in this direction. TRUE focusing can noninvasively deliver light to a dynamically defined focus deep in a scattering medium. This invention opens the door to an even greater paradigm-shifti