Center for Relativistic Laser Science

2019  124th KCS General Meeting 

 It is of great importance to develop techniques to measure optical activity when we investigate biomolecules. Since CD is a extremely weak value, time-resolved CD spectroscopy is experimentally challenging. Here, we demonstrated that it is possible to measure electronic optical activity free-induction-decay (OA-FID) field of tris-(enthylenediamine)3 chloride with dual frequency-comb(DFC). We utilized two phase-locked mode lock lasers whose center frequency is 3100 nm and repetition rate is detuned in slightly different frequency. By measuring parallel FID field in time domain and transforming the measured quantities in time domain into frequency domain via fast Fourier transform by DFC, the complex susceptibility can be obtained, whose imaginary parts and real parts are related to circular dichroism(CD) and optical rotation dispersion(ORD), respectively. By DFC, OA-FID can be measured with simple instrumentation and high data acquisition speed. We anticipate that time-resolved CD spectroscopy with DFC can bring tremendous advantages to the dynamic studies of optically active molecules.