Non-hydrogenic Rydberg series associated with excitons have been identified in ultraclean monolayer TMDCs. Here, we investigated the radiative properties of the excitonic Rydberg series in monolayer MoTe2 based devices and the influence of Fermi level position on the same. Using low temperature (4K) photoluminescence measurements, we observed bright emission from the first three states of the excitonic Rydberg series, namely A1s, 2s and 3s. Upon doping on either electron or hole side, oscillator strengths are rapidly transferred to the corresponding trion (charged exciton/attractive polaron) states associated with the aforementioned neutral excitonic resonances. Energy shifts between different states are observed as a function of gate voltage, indicating strong band-structure renormalization. Our work identifies MoTe2 as a novel platform to realize highly tunable bright light sources or electro-optic modulators in the NIR.
One of the central challenges for practical applications of single-photon sources is the ability to efficiently extract light from a single quantum emitter. A useful single-photon source must emit into a well-defined direction because in practice one can collect light only in a finite solid angle. Here, we propose to harness the exceptional light molding capabilities of photonic metasurfaces to engineer the emission from quantum emitters and achieve highly directional emission.
We have designed a phase gradient reflectarray metasurface, which efficiently collects spontaneous emission from a quantum emitter, located in the far-field (d~5 wavelengths), and redirects it back to the source. By controlling the phase imprinted by the metasurface on the incident light, we control the emission properties of the emitters. We apply this concept to design a metasurface for use with hexagonal boron nitride (hBN) single photon emitters operating at 620 nm. We have observed experimentally bright single photon emission at 620 nm with a remarkably narrow spectral width of zero-phonon line emission from multilayer hBN films synthesized by chemical vapor deposition. Simulations show that at a wavelength of 620 nm, the reflection efficiency of our metasurface is greater than 85%, and that the emission from these emitters are highly directional with deviation from emission in the surface-normal direction of 2∆θ ~ 20°. We will report on experimental measurements of hBN quantum emitters coupled to metasurfaces and describe metasurface designs for coupling of multiple quantum emitters.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.