基于量子弱测量的高精度手征光信号探测研究

Biochemical processes usually accompany the change of molecular configuration, which is relative to the change of the weak optical chiral signal. It is vital to develop an accurate detection technology of the optical chiral signal for deeply understanding biomolecular interaction and pharmacology, pathological processes. However, the optical chiral signal is an extremely weak effect, the current detection technology based on a strong measurement is an optical energy detection, which is limited by the standard quantum limit. The project raises an new principle based on weak quantum measurements to precisely detect the optical chiral signal. By using weak quantum measurements, we put the optical chiral signal into the displacement of photonic spin Hall effect, which is beyond the measurement limit of the current optical chiral signal. We will systematically research the inner relationship between the optical chiral signal and weak quantum measurements. In addition, in order to realize high-precision and sensitive detection of the weak optical chiral signal under solution conditions, we establish an high-precision optical chiral signal experiment platform based on the weak quantum measurements. The detection of optical chiral signal based on the weak quantum measurements is a direct measurement of quantum states, which is insensitive to the external disturbance and has great potential in chiral drug detection at single-molecule level. Moreover, the measurement theory and technology can also be applied in the biomedical engineering, bioscience, and analytical chemistry et.al. This study offers a new idea and important theoretical support to the research of the high-precision biomedical sensor and the medicinal chemistry analysis, and is of great significance to the relevant interdiscipline.

物质的生化过程伴随着分子构型的变化，并关联着弱手征光信号改变。发展高精度的手征光信号检测技术对深入理解生物分子相互作用以及药理、病理过程至关重要。然而，手征光信号是一种极弱的光学效应，现有的探测技术都是基于常规强测量理论的一种光能量探测，受到标准量子极限的限制。本项目提出一种基于量子弱测量的高精度手征光信号探测新原理和新方法，将手征光信号转化为与光子自旋关联的位移分裂，突破现有手征光信号测量极限。我们将系统地研究手征光信号与量子弱测量之间的内在联系，建立基于量子弱测量的手征光信号实验平台，实现溶液环境下弱手征信号的高精度测量。基于量子弱测量的手征光学信号探测是一种无损的直接量子态测量，对外界干扰不敏感，有望实现单分子层面的手性药物分析。所发展的测量理论和技术容易拓展到生物医学工程、生命科学、分析化学等多个学科，为研发高端精密的生物医学传感技术、药化分析技术及装备提供全新的思路和理论支持。

手征光信号（包括圆二色谱，即CD信号；和旋光谱，即ORD信号）关联着生物、化学等过程中的分子构型变化，对深入理解生物分子相互作用以及药理、病理过程至关重要。然而，手征光信号是一种非常弱的光学效应，弱手征光信号的高精度探测面临很多困难和挑战。本项目将量子测量前沿理论创新的应用于手征光信号探测领域，发展出基于量子弱测量的高精度手征光信号探测的理论和技术：（1）提出了振幅和相位分离、同时高精度探测的弱测量理论和方案，并将CD信号对应于弱值的实部，ORD信号对应于弱值的虚部，通过构造恰当的弱测量方案，实现对手征光信号的高精度测量。在通常实验室条件下，获得10-6rad的旋光度测量和手性分子含量的精确测定；（2）提出以强度对比度为指针的弱测量理论，发展出基于对比度指针的弱测量技术。利用对比度指针，可以把弱测量在前端物理层面的弱信号放大及噪声压缩机制，与后端锁相放大经典弱信号检测技术有机的统一起来，实现从前端物理原理到后端技术的全面噪声压缩和弱信号放大，从而极大地提高了参数测量的精度和传感的灵敏度；（3）发展出基于弱值放大的高灵敏度手性介质折射率传感新技术，在实验上实现了10-9RIU的超高折射率传感分辨率，同时降低了实验条件和技术难度，为在线精确手性测定对映体分子含量提供了一种新技术；（4）提出并建立了双指针弱测量理论，使两个指针分别适用于不同的工作范围，恰好相互填补了在动态范围和灵敏度上的缺陷，可解决高灵敏度与大动态范围之间的矛盾，实现大动态范围的物理参数精密测量，对拓展量子弱测量理论及其实际应用具有重要意义。本项目所建立的弱测量理论和方法，可与现有的传统高精度测量技术相融合，且不增加其技术难度和成本，对开发新型高端化学分析、生物医学传感技术、药物检测等仪器装备，以及促进化学、生物医学、生命科学等领域的交叉发展具有重要意义。