image: a, Schematic experimental setup for the CECEM spectroscopy. A linearly polarized light is input into a four-mirror bowtie cavity embedded with a chiral material (CM). The transmitted spectra of left and right circularly polarized (LCP and RCP) eigenmodes are measured separately. b, An example of the LCP and RCP transmitted spectra of 30% sucrose solution around the frequency v4 = 379.48281 THz. c, Representative examples of optical activity measurement of varying designs and their measured performances. The experimental results of this work are represented by the red circle.
Credit: by Wenpeng Zhou, Ya-Ping Ruan, Haodong Wu, Han Zhang, Jiang-Shan Tang, Zhenda Xie, Lei Tang, Yu Wang, Yue-E Ji1, Kunpeng Jia, Cheng-Wei Qiu, Yan-Qing Lu, Keyu Xia
Researchers have developed a new method for precisely analyzing molecules' chirality. This method, known as cavity-enhanced chiral eigenmode (CECEM) spectroscopy, offers several advantages over existing techniques, including the ability to simultaneously measure two key properties of chiral molecules and achieve exceptionally high spectral resolution.
Chirality refers to the "handedness" of a molecule, like a left and right hand. Many biological molecules are chiral, and their handedness can be crucial in their function. Understanding chirality is essential in various fields, including drug development and material science.
CECEM spectroscopy utilizes a special cavity design to analyze chiral materials. The technique can measure two properties simultaneously. The first one is optical rotatory dispersion (ORD), which indicates how much a chiral material rotates the plane of polarized light. The second is circular dichroism (CD), which reflects a chiral material's differential absorption of left and right circularly polarized light.
Existing methods for measuring ORD and CD often require separate measurements and complex setups. CECEM spectroscopy, however, can determine both properties simultaneously using a single, simplified setup. This not only saves time but also reduces the risk of errors.
Another significant advantage of CECEM spectroscopy is its high spectral resolution. This means it can distinguish between closely spaced features in the chiroptical spectrum, providing a more detailed analysis of the chiral molecule. This high resolution is precious for studying complex molecules with intricate chiroptical properties.
The researchers successfully demonstrated CECEM spectroscopy on various chiral materials, including quartz crystals, sugar solutions, and protein solutions. The technique achieved excellent sensitivity, allowing for the detection of weak chiroptical signals.
This new method has the potential to revolutionize chiroptical analysis. Its ability to provide fast, accurate, and high-resolution measurements of chirality will be valuable for researchers in various disciplines studying the properties of chiral molecules.
Journal
eLight
Article Title
Magnetic-free chiral eigenmode spectroscopy for simultaneous sensitive measurement of optical rotary dispersion and circular dichroism