Jamali S, Mkhitaryan V V, Malissa H, Nahlawi A, Popli H, Grünbaum T, Bange S, Milster S, Stoltzfus D M, Leung A E, Darwish T A, Burn P L, Lupton J M, Boehme C
Department of Physics and Astronomy, University of Utah, Salt Lake City, UT, 84112, USA.
Institut für Experimentelle und Angewandte Physik, Universität Regensburg, 93053, Regensburg, Germany.
Nat Commun. 2021 Jan 19;12(1):465. doi: 10.1038/s41467-020-20148-6.
Electron and hole spins in organic light-emitting diodes constitute prototypical two-level systems for the exploration of the ultrastrong-drive regime of light-matter interactions. Floquet solutions to the time-dependent Hamiltonian of pairs of electron and hole spins reveal that, under non-perturbative resonant drive, when spin-Rabi frequencies become comparable to the Larmor frequencies, hybrid light-matter states emerge that enable dipole-forbidden multi-quantum transitions at integer and fractional g-factors. To probe these phenomena experimentally, we develop an electrically detected magnetic-resonance experiment supporting oscillating driving fields comparable in amplitude to the static field defining the Zeeman splitting; and an organic semiconductor characterized by minimal local hyperfine fields allowing the non-perturbative light-matter interactions to be resolved. The experimental confirmation of the predicted Floquet states under strong-drive conditions demonstrates the presence of hybrid light-matter spin excitations at room temperature. These dressed states are insensitive to power broadening, display Bloch-Siegert-like shifts, and are suggestive of long spin coherence times, implying potential applicability for quantum sensing.
有机发光二极管中的电子和空穴自旋构成了用于探索光与物质相互作用超强驱动机制的典型两能级系统。电子和空穴自旋对的含时哈密顿量的弗洛凯解表明，在非微扰共振驱动下，当自旋拉比频率与拉莫尔频率可比时，会出现混合光与物质态，从而在整数和分数g因子下实现偶极禁戒的多量子跃迁。为了通过实验探测这些现象，我们开展了一项电探测磁共振实验，该实验支持振荡驱动场，其幅度与定义塞曼分裂的静态场相当；还采用了一种有机半导体，其特征在于具有最小的局部超精细场，从而能够分辨非微扰光与物质相互作用。在强驱动条件下对预测的弗洛凯态进行的实验证实表明，室温下存在混合光与物质自旋激发。这些缀饰态对功率展宽不敏感，表现出类似布洛赫 - 西格特的频移，并且暗示了长自旋相干时间，这意味着其在量子传感方面具有潜在的适用性。
