Recent experiments on spontaneous emission of atomic matter waves [Krinner et al., Nature (London) 559, 589 (2018); Stewart et al., Phys. Rev. Research 2, 043307 (2020)] open a window into the behavior of quantum emitters coupled to a waveguide. Here we develop an approach based on infinite products to study this system theoretically, without the need to approximate the band dispersion relation of the waveguide. We solve the system for a one-dimensional array of one, multiple, and an infinite number of quantum emitters and compare with the experiments. This leads to a detailed characterization of the decay spectrum, with a family of in-gap bound states, mechanisms for enhanced Markovian emission different from superradiance, and the emergence of matter-wave polaritons.Recent experiments on spontaneous emission of atomic matter waves [Krinner et al., Nature (London) 559, 589 (2018); Stewart et al., Phys. Rev. Research 2, 043307 (2020)] open a window into the behavior of quantum emitters coupled to a waveguide. Here we develop an approach based on infinite products to study this system theoretically, without the need to approximate the band dispersion relation of the waveguide. We solve the system for a one-dimensional array of one, multiple, and an infinite number of quantum emitters and compare with the experiments. This leads to a detailed characterization of the decay spectrum, with a family of in-gap bound states, mechanisms for enhanced Markovian emission different from superradiance, and the emergence of matter-wave polaritons.

arXiv:2108.11759Physical Review AFeb 3, 202212 citations

Controlling light–matter interaction at the nanoscale with cavities and nanoantennas

H. Benisty, Jean‐Jacques Greffet, Philippe Lalanne

Abstract We consider light-matter interaction processes such as emission, absorption, elastic or inelastic scattering and fluorescence by a quantum object such as an atom, a molecule or a quantum dot. The idea of controlling these processes with a resonator (a cavity or a resonant nanoantenna) is to use an intermediate structure which is coupled both to plane waves in vacuum and to the emitters. In this chapter we use a unified approach to discuss any type of resonator using the concept of Green tensor. We review different models to deal with spontaneous emission with the aim of clarifying the connection between classical and quantum points of view. After this analysis of spontaneous emission, we discuss different light-matter interaction processes such as Raman Scattering and Fluorescence both in the linear regime and in the saturation regime. Finally, we discuss how to optimize absorption and introduce the concept of impedance for an optical nanoantenna.Abstract We consider light-matter interaction processes such as emission, absorption, elastic or inelastic scattering and fluorescence by a quantum object such as an atom, a molecule or a quantum dot. The idea of controlling these processes with a resonator (a cavity or a resonant nanoantenna) is to use an intermediate structure which is coupled both to plane waves in vacuum and to the emitters. In this chapter we use a unified approach to discuss any type of resonator using the concept of Green tensor. We review different models to deal with spontaneous emission with the aim of clarifying the connection between classical and quantum points of view. After this analysis of spontaneous emission, we discuss different light-matter interaction processes such as Raman Scattering and Fluorescence both in the linear regime and in the saturation regime. Finally, we discuss how to optimize absorption and introduce the concept of impedance for an optical nanoantenna.

Apr 12, 20220 citations

Spontaneous Emission in Systems of Reduced Dimension

Tyler A. Hill

Matter coupled to light can emit photons. In the absence of an external field this process is known as spontaneous emission. The radiation properties depends in detail the nature of the emitter. In this thesis we consider a two level point-source emitter, and examine how the emission is affected by engineering the local environment. We begin by studying analytically how embedding an emitter in a multi-layer cylindrical structure with radius much smaller than the emission wavelength alters the intensity of the emitted light. We find that for carefully chosen metal-dielectric interfaces, the emission can be strongly enhanced by the plasmonic effect. With this intuition, we experimentally study an InGaN semiconductor quantum dot-in-wire structure as our two level emitter, and manipulate the local field environment by coupling to a lossy plasmonic cavity. We find that the strong enhancement of the field around the quantum dot due to the metal more than compensates for the non-radiative losses, leading to order-of-magnitude increases in the radiative spontaneous emission rate, as well as overall brightness. We then examine how the emission of light can be affected by other nearby emitters. The cooperative effects are strongly dependent on the dimension of the system which controls the electromagnetic mode overlap of the emitters. We present a unified formalism capturing how these cooperative effects change from one dimension to the next. Cooperative light scattering between emitters underpins collective effects such as super- and sub-radiance, and we numerically investigate how our previous results give rise to the key experimental signatures that can be used to identify those phenomena. Specifically, we study how the superadiant decay rate scales with the size of a $2$ -dimensional atomic cloud, and how cooperative effects between a small number of emitters alter the emission spectrum of strongly driven resonance fluorescence.Matter coupled to light can emit photons. In the absence of an external field this process is known as spontaneous emission. The radiation properties depends in detail the nature of the emitter. In this thesis we consider a two level point-source emitter, and examine how the emission is affected by engineering the local environment. We begin by studying analytically how embedding an emitter in a multi-layer cylindrical structure with radius much smaller than the emission wavelength alters the intensity of the emitted light. We find that for carefully chosen metal-dielectric interfaces, the emission can be strongly enhanced by the plasmonic effect. With this intuition, we experimentally study an InGaN semiconductor quantum dot-in-wire structure as our two level emitter, and manipulate the local field environment by coupling to a lossy plasmonic cavity. We find that the strong enhancement of the field around the quantum dot due to the metal more than compensates for the non-radiative losses, leading to order-of-magnitude increases in the radiative spontaneous emission rate, as well as overall brightness. We then examine how the emission of light can be affected by other nearby emitters. The cooperative effects are strongly dependent on the dimension of the system which controls the electromagnetic mode overlap of the emitters. We present a unified formalism capturing how these cooperative effects change from one dimension to the next. Cooperative light scattering between emitters underpins collective effects such as super- and sub-radiance, and we numerically investigate how our previous results give rise to the key experimental signatures that can be used to identify those phenomena. Specifically, we study how the superadiant decay rate scales with the size of a $2$-dimensional atomic cloud, and how cooperative effects between a small number of emitters alter the emission spectrum of strongly driven resonance fluorescence.

Jan 1, 20180 citations

Spontaneous emission from a system of nonidentical two-level atoms

Vladimír Bužek

Czechoslovak Journal of PhysicsOct 1, 19883 citations

2

-dimensional atomic cloud, and how cooperative effects between a small number of emitters alter the emission spectrum of strongly driven resonance fluorescence.