Coherent magnon-phonon interaction is demonstrated in a ferrimagnetic sphere.

Non-reciprocal devices, such as circulators and isolators, are indispensable components in classical and quantum information processing in an integrated photonic circuit. Aside from those applications, the non-reciprocal phase shift is of fundamental interest for exploring exotic topological photonics, such as the realization of chiral edge states and topological protection. However, incorporating low optical-loss magnetic materials into a photonic chip is technically challenging. In this study, we experimentally demonstrate non-magnetic non-reciprocity using optomechanical interactions in a whispering-gallery microresonator, as proposed by Hafezi and Rabl. Optomechanically induced non-reciprocal transparency and amplification are observed, and a non-reciprocal phase shift of up to 40 degrees is demonstrated in this study. The results of this study represent an important step towards integrated all-optical controllable isolators and circulators, as well as non-reciprocal phase shifters.Comment: 5 pages, 4 Figure

Magnons in ferrimagnetic insulators such as yttrium iron garnet (YIG) have recently emerged as promising candidates for coherent information processing in microwave circuits. Here we demonstrate optical whispering gallery modes of a YIG sphere interrogated by a silicon nitride photonic waveguide, with quality factors approaching 10 6 in the telecom c-band after surface treatments. Moreover, in contrast to conventional Faraday setup, this implementation allows input photon polarized colinearly to the magnetization to be scattered to a sideband mode of orthogonal polarization. This Brillouin scattering process is enhanced through triply resonant magnon, pump and signal photon modes -all of whispering gallery nature -within an "optomagnonic cavity". Our results show the potential use of magnons for mediating microwave-to-optical carrier conversion.Hybrid magnonic systems have been emerging recently as an important approach towards coherent information processing 1-9 . The building block of such systems, magnon, is the quantized magnetization excitation in magnetic materials 10,11 . Its great tunability and long lifetime make magnon an ideal information carrier. Particularly, in magnetic insulator yttrium iron garnet (YIG), magnons interact with microwave photons through magnetic dipole interaction, which can reach the strong and even ultrastrong coupling regime thanks to the large spin density in YIG 4-6 . Besides, the magnon can also couple with the elastic wave 12,13 and optical light 14,15 , it is of great potential as an information transducer that mediates inter-conversion among microwave photon, optical photon and acoustic phonon. Long desired functions, such as microwave-to-optical conversion, can be realized on such a versatile platform.Magneto-optical (MO) effects such as Faraday effect have been long discovered and utilized in discrete optical device applications [16][17][18] . Based on such effects, magnons can coherently interact with optical photons. On the one hand, magnon can be generated by optical pumps [19][20][21][22] . On the other hand, optical photons can be used to probe magnon through Brillouin light scattering (BLS) 15,23 . However, in previous studies the typical geometries are all thin film or bulk samples inside which the optical photon interacts with magnon very weakly, usually only through a single pass. For high efficient magnon-photon interaction, it is desirable to obtain triple resonance condition of high quality (Q) factor modes, i.e., the magnon, the input and the output optical photons are simultaneously on resonance.In this Letter, we demonstrate the magnon-photon interaction in a high Q optomagnonic cavity which simultaneously supports whispering gallery modes (WGMs) of optical and magnon resonances. With high-precision fabrication and careful surface treatment, the widely used YIG sphere structure, which is inherently an excellent magnonic resonator, exhibits high optical Q factors in our measurements. YIG has a high refractive index (2.2 in the telecom c-band), which poses...

No abstract

Quantum-photonic chips, which integrate quantum light sources alongside active and passive optical elements, as well as single-photon detectors, show great potential for photonic quantum information processing and quantum technology. Mature semiconductor nanofabrication processes allow for scaling such photonic integrated circuits to on-chip networks of increasing complexity. Second-order nonlinear materials are the method of choice for generating photonic quantum states in the overwhelming majority of linear optic experiments using bulk components, but integration with waveguide circuitry on a nanophotonic chip proved to be challenging. Here, we demonstrate such an on-chip parametric down-conversion source of photon pairs based on second-order nonlinearity in an aluminum-nitride microring resonator. We show the potential of our source for quantum information processing by measuring the high visibility anti-bunching of heralded single photons with nearly ideal state purity. Our down-conversion source yields measured coincidence rates of 80 Hz, which implies MHz generation rates of correlated photon pairs. Low noise performance is demonstrated by measuring high coincidence-to-accidental ratios. The generated photon pairs are spectrally far separated from the pump field, providing great potential for realizing sufficient on-chip filtering and monolithic integration of quantum light sources, waveguide circuits and single-photon detectors.

Developments in photonic chips have spurred photon based classical and quantum information processing, attributing to the high stability and scalability of integrated photonic devices [1,2]. Optical nonlinearity [3] is indispensable in these complex photonic circuits, because it allows for classical and quantum light sources, all-optical switch, modulation, and non-reciprocity in ambient environments. It is commonly known that nonlinear interactions are often greatly enhanced in the microcavities [4]. However, the manifestations of coherent photon-photon interaction in a cavity, analogous to the electromagnetically induced transparency [5], have never been reported on an integrated platform. Here, we present an experimental demonstration of the coherent photon-photon interaction induced by second order optical nonlinearity (χ (2) ) on an aluminum nitride photonic chip. The non-reciprocal nonlinear optic induced transparency is demonstrated as a result of the coherent interference between photons with different colors: ones in the visible wavelength band and ones in the telecom wavelength band. Furthermore, a wide-band frequency conversion with an almost unit internal (0.14 external) efficiency and a bandwidth up to 0.76 GHz is demonstrated.The importance of integrating nonlinear devices on a photonic chip has become more prominent due to the devices' small foot-prints and large scalability [6,7]. Second order optical nonlinearity (χ (2) ) is one of the most widely explored properties in photonics, utilizing various nonlinear materials [8][9][10][11][12][13]. χ (2) nonlinearity enables the coupling between photons with very different colors, acting as the basis for many important applications such as second harmonic generation, spontaneous parametric down conversion, optical parametric amplification and oscillation. Due to the high quality factor to mode volume ratio, the nonlinear interaction strength is expected to be boosted in optical cavities. Preliminary results in millimeter sized optical resonators have already shown such trend, where efficient second harmonic generation [14,15] and sum frequency generation [16] are demonstrated. However, the realized nonlinear interaction strength on an integrated platform is normally weak, hindered by the challenges of fabricating small size, low loss optical circuits with materials featuring high χ (2) nonlinearity.In this Letter, we demonstrate coherent interaction between photons of different colors on a scalable aluminum nitride-on-insulator [12] chip based on χ (2) optical nonlinearity. The nonlinear optic induced transparency (NOIT), as an analogue to electromagnetically induced transparency resulting from coherent photon-atom [5] or photon-phonon interactions [17][18][19][20], is reported. Due to the inherent phase matching condition, the χ (2) nonlinearity based coherent interaction and the accompanying NOIT phenomenon are non-reciprocal [19,20], which permits future applications such as non-magnetic, ultrafast optical isolators [21][22][23]. We further realize ...

Flexible organic photonic devices for high-performance optical information processing can be produced via ink-jet printing.

No abstract