Quantum Optics Lab @ Purdue
RESEARCH
We are an experimental quantum optics group at Purdue University working at the interface of atomic, molecular, and optical physics. Our research focuses on three areas: generating remote entanglement between individually trapped atoms, assembling ultracold LiCs molecules for quantum chemistry and quantum simulation, and engineering single-photon sources from organic molecules in photonic structures. Our lab takes three complementary approaches:
Photon Generation with Organic Molecules
Ultracold Quantum Chemistry with Li and Cs
Ultracold polar molecules offer a powerful platform for quantum simulation of strongly correlated many-body systems. The permanent electric dipole moment of polar molecules provides strong, long-range, and anisotropic interactions that can be precisely controlled with external electric and microwave fields. These dipolar interactions enable the study of exotic quantum phases — including topological states, unconventional superconductivity, and lattice gauge theories — that require long-range coupling difficult to achieve in other quantum platforms.
Our group pioneered the bottom-up assembly of single molecules from individually trapped ultracold atoms in optical tweezers. We trap individual atoms of lithium and cesium, cool them to their motional ground states, and coherently associate them into single LiCs molecules. This atom-by-atom approach provides complete quantum state control over both internal and external degrees of freedom. Our landmark work demonstrated the first assembly of a single molecule from two individually prepared atoms (Liu et al., Science 2018) and the first coherent optical creation of a single molecule in a tweezer (Yu et al., Phys. Rev. X 2021).
We are now scaling this platform toward arrays of molecular tweezers for programmable quantum simulation. Key recent advances include high-fidelity imaging of single atoms with over 2000 consecutive images without loss (Blodgett et al., Phys. Rev. Lett. 2023), narrow-line electric quadrupole cooling of single cesium atoms for enhanced motional ground-state preparation (Blodgett et al., Phys. Rev. A 2025), and a generalized theory for optical cooling of trapped atoms with spin (Phatak et al., Phys. Rev. A 2024). These techniques establish the experimental toolkit for creating and controlling arrays of ultracold LiCs molecules with single-site resolution for quantum simulation of condensed matter Hamiltonians.
Photon Generation with Organic Molecules
Organic molecules in the solid state are a remarkable platform for quantum photonics and many-body quantum optics. Certain polycyclic aromatic hydrocarbons (PAHs), such as dibenzoterrylene (DBT), exhibit lifetime-limited optical linewidths at cryogenic temperatures and emit predominantly into the zero-phonon line, making them nearly ideal single-photon sources. When embedded in a crystalline host matrix, these molecules can be spaced at nanometric separations while maintaining excellent quantum optical properties.
Our group investigates coherent dipole-dipole interactions between organic emitters for applications in quantum networking and fundamental many-body physics. We demonstrated the first observation of superradiant and subradiant states in lifetime-limited organic molecules, achieved through a novel laser-induced frequency tuning technique that brings pairs of emitters into resonance (Lange et al., Nature Physics 2024). This light-induced approach is uniquely scalable, enabling the prospect of controlling collective interactions among many emitters simultaneously.
Building on these results, we have developed a hybrid molecular-nanophotonic platform that integrates organic emitters with photonic integrated circuits for on-chip cavity quantum electrodynamics (QED) and collective interactions (Lange et al., ACS Nano 2026). We are also exploring vapor-phase assembly techniques for depositing high-quality molecular emitter crystals directly onto photonic structures, opening a route to wafer-scale quantum photonic devices (Keni et al., 2026). Our recent review article provides a comprehensive overview of many-body entanglement phenomena in solid-state molecular emitters and outlines the path toward scalable quantum networks and simulators (Daggett et al., Nature Reviews Materials 2026).
