[Paper Review] Chiral quantum optics: recent developments, and future directions

D. G. Suárez-Forero, Mahmoud Jalali Mehrabad+3 more|arXiv (Cornell University)|Nov 10, 2024

Molecular spectroscopy and chiralityChemistry3 citations

TL;DR

This paper reviews recent advances in chiral quantum optics, focusing on solid-state platforms like quantum dots, 2D materials, and microcavity polaritons integrated into photonic structures. It highlights spin-momentum locking and time-reversal symmetry breaking as key mechanisms enabling non-reciprocal light-matter interactions, and explores their potential for realizing exotic many-body quantum phases such as chiral superradiance and fractional quantum Hall physics beyond the dipole approximation.

ABSTRACT

Chiral quantum optics is a growing field of research where light-matter interactions become asymmetrically dependent on momentum and spin, offering novel control over photonic and electronic degrees of freedom. Recently, the platforms for investigating chiral light-matter interactions have expanded from laser-cooled atoms and quantum dots to various solid-state systems, such as microcavity polaritons and two-dimensional layered materials, integrated into photonic structures like waveguides, cavities, and ring resonators. In this perspective, we begin by establishing the foundation for understanding and engineering these chiral light-matter regimes. We review the cutting-edge platforms that have enabled their successful realization in recent years, focusing on solid-state platforms, and discuss the most relevant experimental challenges to fully harness their potential. Finally, we explore the vast opportunities these chiral light-matter interfaces present, particularly their ability to reveal exotic quantum many-body phenomena, such as chiral many-body superradiance and fractional quantum Hall physics.

Motivation & Objective

• To establish a foundational understanding of chiral quantum optics through key concepts like spin-momentum locking and time-reversal symmetry breaking.
• To review cutting-edge experimental platforms—particularly solid-state systems—enabling chiral light-matter interactions beyond traditional atomic and quantum dot setups.
• To identify and address major experimental challenges in achieving full control over chiral photonic and electronic degrees of freedom.
• To explore the potential of chiral quantum optics for observing novel many-body quantum phenomena, including chiral superradiance and fractional quantum Hall effects.
• To outline future research directions, including non-Markovian dynamics, higher-dimensional photonic systems, and non-linear chiral many-body regimes.

Proposed method

• Theoretical analysis of photonic spin-momentum locking using Maxwell’s equations, showing how transverse polarization and propagation direction become locked due to divergence-free electric fields.
• Derivation and application of a non-reciprocal master equation to describe chiral light-matter interactions under time-reversal symmetry breaking.
• Systematic review of photonic platforms: 2D cavities, ring resonators, waveguides, and open cavities, emphasizing their role in enabling chiral coupling.
• Investigation of active materials including quantum dots, transition metal dichalcogenides (TMDs), and microcavity polaritons as tunable chiral emitters.
• Extension of the dipole approximation to include orbital angular momentum (OAM) of light, enabling chiral coupling to electrons in quantum Hall systems.
• Theoretical modeling of chiral many-body dynamics, including superradiance and dissipative phases, using non-Markovian and topological approaches.

Experimental results

Research questions

• RQ1 How can spin-momentum locking in photonic waveguides be engineered to enable directional emission and chiral light-matter coupling?
• RQ2 What are the key experimental challenges in realizing robust chiral interactions in solid-state platforms like TMDs and polaritonic systems?
• RQ3 To what extent can chiral quantum optics enable the observation of exotic many-body phases such as chiral superradiance and fractional quantum Hall physics?
• RQ4 How do non-dipolar light-matter interactions, particularly involving orbital angular momentum (OAM), influence electron dynamics in 2D and topological systems?
• RQ5 What theoretical frameworks are needed to describe non-Markovian and topologically non-trivial chiral open quantum systems beyond quadratic approximations?

Key findings

• Spin-momentum locking in dielectric waveguides leads to position-dependent circular polarization and directional emission, enabling chiral coupling between emitters and photonic modes.
• Non-reciprocal master equations successfully describe chiral light-matter interactions under time-reversal symmetry breaking, with experimental validation in systems like atoms in optical fibers.
• Recent experiments have demonstrated chiral superradiant bursts in atomic arrays, confirming theoretical predictions of collective chiral emission beyond the standard Dicke model.
• Orbital angular momentum (OAM) of light can be transferred to electrons in the quantum Hall regime, enabling OAM-selective optical transitions and photocurrent generation in graphene and other 2D materials.
• Chiral coupling beyond the dipole approximation reveals new pathways for controlling electron chirality and generating chiral photons, particularly in materials like GaAs and HgCdTe.
• Theoretical frameworks for non-Markovian and topological chiral dynamics are emerging, suggesting new avenues for realizing non-equilibrium quantum phases in higher-dimensional photonic systems.