Prof.  Yi  Jiang
School of Chemistry and Life Sciences, Nanjing University of Posts and Telecommunications, Nanjing,  China

Title: Giant nonlinear Raman responses from organic semiconductors

Abstract:

Organic semiconductors exhibit unique semiconducting behaviour due toπ-electron delocalization along their molecular chains, making them attractive for various optoelectronic applications. However, their low optical damage thresholds have limited their use in nonlinear optics, particularly in stimulated Raman scattering. Here we demonstrate a general method to significantly amplify molecular vibrations in organic semiconductors by utilizing spectrally tailored gain from stimulated emission, bypassing the necessity for traditional optical cavities. This method achievesRaman thresholds as low as ~10-50 μJ/cm2, outperforming current Raman lasers by four orders of magnitude.The resulting nonlinear Raman response leads to cascaded Raman emission characterized by pump-dependent emission efficiency, a nonlinearity factor of 3.8, a signal-to-noise ratio of 30.9 dB, and a bandwidth of 110 nm.Our study opens exciting prospects for the development of compact, efficient Raman amplifiers and lasers, leveraging the unique properties of organic semiconductors for advanced photonic applications, including high-sensitivity spectroscopy and versatile frequency conversion technologies.

The speaker will also introduce the recent researches on organic semiconductor lasers.

References:

1. Y. Jiang, W.-Y. Lai,* et al.,Nat. Mater., 2025,24, 1091.

2. Yi Jiang, W.-Y. Lai,* K. W. Cheah,* et al.,Angew. Chem. Int. Ed., 2021,60, 10007.

3. Yi Jiang, W.-Y. Lai,* et al.,Chem. Soc. Rev., 2020,49, 5885.

4. Yi Jiang, W.-Y. Lai,* et al.,Adv. Funct. Mater., 2019,29, 1806719.

5. Y. Huang,Yi Jiang,* K. W. Cheah,* et al.,Adv. Opt. Mater., 2025,13, 2402455.

6. Yi Jiang, K. W. Cheah,*Adv. Opt. Mater.,2022,10, 2102472.

Biography:

Dr. Yi Jiang is a Professor in State Key Laboratory of Flexible Electronics (LoFE), Nanjing University of Posts & Telecommunications. He got his PhD in Nanjing University of Posts & Telecommunications under the supervision of Prof. Wen-Yong Lai in 2018. During his PhD career, he separately joined in Prof. Donal D. C. Bradley’s group in Department of Physics at University of Oxford and Hong Kong Baptist University supervised by Prof. Kok Wai Cheah as visiting scientist. Since then, he went on to work in Hong Kong Baptist University as a postdoctoral fellow for nearly 5 years. After 2023, he backed to Nanjing University of Posts & Telecommunications to continue his research as professor. His current research mainly focuses on organic semiconductor lasers, organic Raman lasers, optoelectronic/laser devices, and non-linear optics. Currently, he has published over 20 papers in Nat. Mater., Angew, Chem. Soc. Rev., etc.