Noiseless photonic non-reciprocity via optically-induced magnetization

Abstract

The realization of optical non-reciprocity is crucial for many applications, and also of fundamental importance for manipulating and protecting the photons with desired time-reversal symmetry. Recently, various new mechanisms of magnetic-free non-reciprocity have been proposed and implemented, avoiding the limitation of the strong magnetic field imposed by the Faraday effect. However, due to the difficulties in separating the signal photons from the drive laser and the noise photons induced by the drive laser, these devices exhibit limited isolation performances and their quantum noise properties are rarely studied. Here, we demonstrate an approach of magnetic-free non-reciprocity by optically-induced magnetization in an atom ensemble. Excellent isolation (highest isolation ratio is $$51.{5}_{-2.5}^{+6.5}\ {\rm{dB}}$$ 51 . 5 − 2.5 + 6.5 dB ) is observed over a power dynamic range of 7 orders of magnitude, with the noiseless property verified by quantum statistics measurements. The approach is applicable to other atoms and atom-like emitters, paving the way for future studies of integrated photonic non-reciprocal devices.

Noiseless single-photon isolator at room temperature

“…To bypass this limitation, considerable theoretical and experimental efforts have been made to explore the magnetic-free ONRs by using various physical mechanisms, including nonlinear effects [5][6][7][8] , spatiotemporal modulation of permittivity [9][10][11][12][13][14] , optomechanical interactions [15][16][17][18] , moving Bragg lattices in atoms [19][20][21] , chiral quantum systems [22][23][24] , and random thermal-motion of atoms [25][26][27][28][29][30][31] . As we know, most of the reported schemes work in the classical region with weak coherent light.…”

“…For single-photon isolators, it is not only required to have unidirectional transmittance but also more importantly, to maintain the quantum characteristics of input single photons from the selected direction. That is, the system should not introduce much additional noise, including the classical background noise 31 and quantum noise 32 .…”

Complex skin modes in non-Hermitian coupled laser arrays

“…In optics, such lattices have been only implemented in synthetic dimensions, leading to the observation of light funneling with interface localization 12 , non-Hermitian bands with arbitrary winding numbers 13 , and complex-energy braiding 14 . However, the realization of such non-reciprocal coupling processes in real space have so far remained difficult if not elusive [34][35][36] .…”

Optical Isolation with Optical Parametric Amplification in an Atomic System

“…In particular, considering the advancement in realizing the miniaturization and integration of atomic samples, [ 27,28 ] multilevel atomic systems with readily manipulated light‐induced atomic coherence have spawned flourishing achievements in optical nonreciprocity by taking advantages of inherent atomic properties such as the thermal‐motion induced Doppler shift [ 18–20 ] and the transition rules between energy levels. [ 29 ] Strikingly, the recently reported collision‐induced optical nonreciprocity in an atomic configuration driven by three laser fields has reached the maximum isolation ratio of ≈40 dB with the insertion loss ≤1 dB and a bandwidth of ≈200 MHz for isolation ratio ≥30 dB. [ 21 ] Also, a high‐performance optical isolation in single‐photon level was realized via electromagnetically induced transparency in an atomic vapor cell.…”