Author Affiliations
1 Department of Physics, State Key Laboratory of Surface Physics and Key Laboratory of Micro- and Nano-Photonic Structure (MOE), Fudan University, Shanghai 200433, China.
2 Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA.
3 School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China.
The surface/interface species in perovskite oxides play essential roles in many novel emergent physical phenomena and chemical processes. With low eigen-energies in the terahertz region, such species at buried interfaces remain poorly understood due to the lack of feasible surface-specific spectroscopic probes to resolve the resonances. Here, we show that polarized phonons and two-dimensional electron gas at the interface can be characterized using surface-specific nonlinear optical spectroscopy in the terahertz range. This technique uses intra-pulse difference frequency mixing process, which is allowed only at the surface/interface of a centrosymmetric medium. Submonolayer sensitivity can be achieved using the state-of-the-art detection scheme for the terahertz emission from the surface/interface. Through symmetry analysis and proper polarization selection, background-free Drude-like nonlinear response from the two-dimensional electron gas emerging at the LaAlO3/SrTiO3 or Al2O3/SrTiO3 interface was successfully observed. The surface/interface potential, which is a key parameter for SrTiO3-based interface superconductivity and photocatalysis, can now be determined optically in a nonvacuum environment via quantitative analysis on the phonon spectrum that was polarized by the surface field in the interfacial region. The interfacial species with resonant frequencies in the THz region revealed by our method provide more insights into the understanding of physical properties of complex oxides.
Ultrafast Science
2023, 3(1): 0042
Lehong Huang 1,2,3,4Haochuan Li 1Zhiguo Li 1,3,4Wenbo Zhang 1,2,3[ ... ]Shiping Guo 2
Author Affiliations
1 Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi’an 710119, China
2 School of Physics, Xi’an Jiaotong University, Xi’an 710049, China
3 University of Chinese Academy of Sciences, Beijing 100049, China
4 Key Laboratory of Space Precision Measurement Technology, Chinese Academy of Sciences, Xi’an 710119, China
5 e-mail:
6 e-mail:
Although the effective “stealth” of space vehicles is important, current camouflage designs are inadequate in meeting all application requirements. Here, a multilayer wavelength-selective emitter is demonstrated. It can realize visible light and dual-band mid-infrared camouflage with thermal control management in two application scenarios, with better effect and stronger radiation cooling capability, which can significantly improve the stealth and survivability of space vehicles in different environments. The selective emitter demonstrated in this paper has the advantages of simple structure, scalability, and ease of large-area fabrication, and has made a major breakthrough in driving multiband stealth technology from simulation research to physical verification and even practical application.
Photonics Research
2023, 11(5): 839

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