Brosseau Patrick, Palato Samuel, Seiler Hélène, Baker Harry, Kambhampati Patanjali
Department of Chemistry, McGill University, Montreal, Quebec H3A 0B8, Canada.
J Chem Phys. 2020 Dec 21;153(23):234703. doi: 10.1063/5.0021381.
Two-quantum variants of two-dimensional electronic spectroscopy (2DES) have previously been used to characterize multi-exciton interactions in molecules and semiconductor nanostructures though many implementations are limited by phasing procedures or non-resonant signals. We implement 2DES using phase-cycling to simultaneously measure one-quantum and two-quantum spectra in colloidal CdSe quantum dots. In the pump-probe geometry, fully absorptive spectra are automatically acquired by measuring the sum of the rephasing and nonrephasing signals. Fifth-order two-quantum spectroscopy allows for direct access to multi-exciton states that may be obscured in excited state absorption signals due to population relaxation or third-order two-quantum spectra due to the non-resonant response.
二维电子光谱（2DES）的双量子变体此前已被用于表征分子和半导体纳米结构中的多激子相互作用，不过许多实现方式受到相位程序或非共振信号的限制。我们利用相位循环实现2DES，以同时测量胶体CdSe量子点中的单量子和双量子光谱。在泵浦-探测几何结构中，通过测量重相位和非重相位信号的总和自动获取全吸收光谱。五阶双量子光谱能够直接探测到由于布居弛豫可能在激发态吸收信号中被掩盖的多激子态，或者由于非共振响应在三阶双量子光谱中被掩盖的多激子态。
