Controlling single-photon transport in waveguides with finite cross section

2016

Opt. Lett.

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confidence: 99%

Quantum scattering theory of a single-photon Fock state in three-dimensional spaces

Liu

2016

Opt. Lett.

“…Obviously, the total reflection occurs in the resonance condition in previous studies [5,8,9,13,21], the Lamb shift ∆(ω a ), which arises from the renormalization of the TLS's energy level, has been ignored due to the use of the quadratic or linear dispersion approximation.…”

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confidence: 99%

“…However, the position of the total reflection experiences a blue shift to ω a due to the renormalization, which becomes larger as the coupling strength increases. We note that total reflection also occurs when E → Ω 1 + 0 + , which is referred to as the cut-off frequency resonance [21]. When the incident energy E is above Ω 2 , higher-order modes and the induced multi-channel interference effects must be taken into account.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Waveguide quantum electrodynamics: Controllable channel from quantum interference

Sun

2014

Phys. Rev. A

Self Cite

We study a waveguide QED system with a rectangular waveguide and a two-level system (TLS) inside, where the transverse modes TMmn define the quantum channels of guided photons. It is discovered that the loss of photons in the TM11 channel into the others can be overcome by replacing it with a certain coherent superposition of TMmn channels, which is named as the controllable channel (CC) as the photons in CC can be perfectly reflected or transmitted by the TLS, and never lost into the other channels. The dark state emerges when the photon is incident from one of the scattering-free channels (SFCs) orthogonal to CC. The underlying physics mechanism is the multi-channel interference associated with Fano resonance.PACS numbers: 42.50. Gy, 42.50.Ct, 03.65.Nk In a fully-quantum network based on single photon carriers to process quantum information, the essential task is to coherently control photon propagation by a local quantum node [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. To this end, a hybrid system consisting of a one-dimensional (1D) waveguide coupled to a two-level system (TLS) is extensively studied for physical implementation of the quantum node acting as a quantum switch [4][5][6][7][8][9][10][11][12] or a single photon transistor [13,14]. With the single mode approximation for a waveguide with infinitesimal cross section, the total reflection of single photons by the TLS was found to be responsible for the dominant functions of quantum devices.However, a realistic waveguide with a finite cross section necessarily possesses transverse modes. Thus, photons guided in the realistic waveguide may be in different quantum channels defined by transverse modes. Each transverse mode has a cut-off frequency for the corresponding guiding mode. To demonstrate multi-channel effects on single-photon scattering, Ref.[21] made an approximation using two modes and a quadratic dispersion relation, and showed that the guided photon cannot be totally reflected due to the loss from one mode to the other. In other words, the quantum device oriented functions we desire can not be well achieved . In order to overcome such multi-channel loss, we will revisit the waveguide QED by considering a realistic hybrid system without any over-approximation.In this letter, we study single-photon scattering by a TLS locally embedded in a waveguide of finite rectangular cross section. In our approach, both the real dispersion relation and multi-channel effects are exactly taken into account. As for the multi-channel induced loss, we find that there exists a unique controllable channel (CC) defined by a particular superposition of the transverse magnetic modes TM mn , in which the guided photons can * Electronic address: cpsun@csrc.ac.cn; URL: http://www.csrc.ac.cn/suncp/ be well controlled by the TLS since the guided photons in the complementary channels orthogonal to CC are completely decoupled from the TLS. Such a scattering free channel (SFC) behaves as the dark state to support the electromagnetically induc...

“…A photon coming toward the atom will first disappear, and appear later, i.e., the propagating photon is scattered by the atom. Taking the state |k, φ n ≡ a † k |0 ⊗ |φ n (|0 represents the photonic vacuum state in the waveguide and n = ±) as the input state, which represents the atom in the internal state |φ n and the photon in the kth mode, the stationary state |ψ kn can be given by the Lippman-Schwinger equation [21,25,26] |ψ kn = |k, n + 1…”

Section: Formalism Of the Frequency Convertermentioning

confidence: 99%

Controllable single-photon frequency converter via a one-dimensional waveguide

Wang

et al. 2014

Phys. Rev. A

Self Cite

We propose a single-photon frequency converter via a one-dimensional waveguide coupled to a V -type atom. The on-demand classical field allows the atom to absorb a photon with a given frequency, then emit a photon with a carried frequency different from the absorbed one. The absorption and re-emission process is formulated as a two-channel scattering process. We study the single-photon frequency conversion mechanism in two kinds of realistic physical system: coupled resonator waveguide with cosine dispersion relation and an optical waveguide with linear dispersion relation respectively. We find that the driving field prefers weak in coupled resonator waveguide but arbitrarily strong in optical waveguide to achieve an optical transfer efficiency.