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Christian C. Ruiz Madera

Publications and source records attributed to Christian C. Ruiz Madera.

2 recordsLinked to original sources

Toward triggered generation of indistinguishable single-photons from MoTe$_2$ quantum emitters

Single-photon sources operating at telecom wavelengths are fundamental components for long-distance optical quantum communication and information processing. Two-dimensional (2D) transition metal dichalcogenides (TMDs) offer a promising platform for such sources, but their development has been hindered by limited spectral range and poor single-photon indistinguishability. Here, we demonstrate a reproducible and systematic approach for generating near-infrared (1090-1200 nm) quantum emitters in bilayer MoTe$_2$ using deterministic strain and defect engineering. These emitters exhibit strong linear polarization (DOLP $>70%$), sub-nanosecond lifetimes ($τ\sim$ 130-450 ps), high single-photon purity with triggered $g^{(2)}(0)$ values as low as $\sim$0.01 ($\sim$0.16) under p-shell (quasi-resonant) excitation, and resolution-limited emission ($\sim$150 $μ$eV). Electrostatic biasing enables tuning over a $\sim$3 meV range, suppresses photon bunching, and significantly shortens radiative lifetimes, yielding narrow emission with ratios of experimental to transform-limited linewidths as low as $R\sim55$. Most notably, two-photon interference measurements reveal a Hong-Ou-Mandel visibility of $V_{HOM}\sim$ 7.1$%$ (3.6$%$), and up to $V_{HOM}\sim$ 60$%$ ($\sim$40$%$) with post-selection by temporal filtering under p-shell (quasi-resonant) excitation. To our knowledge, this presents the highest reported indistinguishability for TMD quantum emitters and the first such demonstration for MoTe$_2$ platform. These results establish MoTe$_2$ as a viable platform for tunable, low-noise, high-purity single-photon sources with state-of-the-art indistinguishability for TMD quantum emitters, paving the way for their integration into telecom-compatible quantum photonic technologies.

physics.optics↗

Telecom-band site-controlled quantum dots with engineered low fine-structure splitting

Deterministic quantum light sources emitting at telecom wavelengths with vanishing fine-structure splitting (FSS) are essential components for scalable quantum communication. While self-assembled Stranski-Krastanov (SK) quantum dots (QDs) are high-quality emitters, their random positioning and shape-induced anisotropy typically limit their use in entangled-photon applications. In this work, we demonstrate site-controlled SK growth where InAs/InP QDs nucleate at the symmetric apexes of truncated InP nanopyramids. Confining adatom diffusion to a small, symmetric nucleation area suppresses anisotropic growth, promoting the nucleation of highly symmetric QDs with FSS reduced to values below our statistically validated resolution limit of $9.2~μ$eV. At the same time, lithographically defined nucleation sites enable deterministic control of the QD position, overcoming the limitations of conventional SK growth. The high structural quality of single symmetric QDs is evidenced by the single-photon character of the emission ($g^{(2)}(0)=0.07^{+0.27}_{-0.07}$) spanning the S, C, and L telecom bands, with no evidence of lithography-induced defects affecting emission dynamics. These results demonstrate that tailoring QD symmetry through nanopyramid growth engineering provides a route toward site-controlled emitters suitable for entangled photon generation and integrated quantum photonics devices.

cond-mat.mes-hall↗