Continuous Wave Sum Frequency Generation and Imaging of Monolayer and Heterobilayer Two-Dimensional Semiconductors
- Columbia Univ., New York, NY (United States); Univ. of California, Berkeley, CA (United States); OSTI
- Columbia Univ., New York, NY (United States)
- Naval Research Lab. (NRL), Washington, DC (United States)
- Columbia Univ., New York, NY (United States); Univ. of California, Berkeley, CA (United States)
- Naval Research Lab. (NRL), Washington, DC (United States); Univ. of Maryland, College Park, MD (United States)
- National Inst. for Materials Science (NIMS), Tsukuba (Japan)
Here, we report continuous-wave second harmonic and sum frequency generation from two-dimensional transition metal dichalcogenide monolayers and their heterostructures with pump irradiances several orders of magnitude lower than those of conventional pulsed experiments. The high nonlinear efficiency originates from above-gap excitons in the band nesting regions, as revealed by wavelength-dependent second order optical susceptibilities quantified in four common monolayer transition metal dichalcogenides. Using sum frequency excitation spectroscopy and imaging, we identify and distinguish one- and two-photon resonances in both monolayers and heterobilayers. Data for heterostructures reveal responses from constituent layers accompanied by nonlinear signal correlated with interlayer transitions. We demonstrate spatial mapping of heterogeneous interlayer coupling by sum frequency and second harmonic confocal microscopy on heterobilayer MoSe2/WSe2.
- Research Organization:
- Columbia Univ., New York, NY (United States); Energy Frontier Research Centers (EFRC) (United States). Programmable Quantum Materials (Pro-QM)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- SC0019443
- OSTI ID:
- 1767655
- Journal Information:
- ACS Nano, Journal Name: ACS Nano Journal Issue: 1 Vol. 14; ISSN 1936-0851
- Publisher:
- American Chemical Society (ACS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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charge transport
confocal microscopy
defects
exciton
magnetism and spin physics
materials and chemistry by design
mesoscale science
mesostructured materials
nonlinear optics
optics
sum frequency generation
superconductivity
synthesis (novel materials)
synthesis (self-assembly)
two-dimensional semiconductors
valleytronics
van der Waals heterostructures