Photonic integrated circuits with bound states in the continuum

Abstract

Waves that are perfectly confined in the continuous spectrum of radiating waves without interaction with them are known as bound states in the continuum (BICs). Despite recent discoveries of BICs in nanophotonics, full routing and control of BICs are yet to be explored. Here, we experimentally demonstrate BICs in a fundamentally new photonic architecture by patterning a low-refractive-index material on a high-refractive-index substrate, where dissipation to the substrate continuum is eliminated by engineering the geometric parameters. Pivotal BIC-based photonic components are demonstrated, including waveguides, microcavities, directional couplers, and modulators. Therefore, this work presents the critical step of photonic integrated circuits in the continuum, and enables the exploration of new single-crystal materials on an integrated photonic platform without the fabrication challenges of patterning the single-crystal materials. The demonstrated lithium niobate platform will facilitate development of functional photonic integrated circuits for optical communications, nonlinear optics at the single photon level as well as scalable photonic quantum information processors.

Strong coupling of single quantum dots with low-refractive-index/high-refractive-index materials at room temperature

“…When k y d = 2m, an F-P resonance occurs for transverse magnetic (TM) modes, where k y is the wave vector of the y component of the TM modes, matching that of the TE modes; d is the thickness of the lowrefractive-index film; and m is an integer. According to (28,29), the loss  of the TM mode is inversely proportional to the attenuation length, which we can express as…”

“…Most of the realized photonic BICs occurred in the conventional architecture of a highrefractive-index material surrounded by a low-refractive environment. Recently, researchers theoretically (28) and experimentally (29) demonstrated that photonic BICs existed in low-refractive-index materials on high-refractive-index substrates. In these low-refractive-index/ high-refractive-index hybrid structures, optical dissipation is prohibited because of the destructive interference of various dissipative channels under certain geometric parameters.…”

Trends in Quantum Nanophotonics

“…[ 58 ] The Q ‐factor is found to be proportional to α −2 , where α is the asymmetry‐factor of the structure. More recently, BIC was also demonstrated in the hybrid plasmonic–photonic system, [ 59 ] integrated photonic circuit [ 60 ] and zero index material. [ 61 ]…”

High-dimensional communication on etchless lithium niobate platform with photonic bound states in the continuum

“…This concept was first proposed by von Neumann and Wigner in 1929 1 with a mathematically constructed three-dimensional potential that can support perfectly confined states in a continuous band. Recently, advancement in nanofabrication technologies has triggered fast development of BICs in photonics [10][11][12][13][14][15][16] , and the demonstrated physical phenomena are being applied to the areas of sensors 17,18 , lasers 11 , filters 19 , and integrated photonics 14,15,[20][21][22][23] . For integrated photonics, resonances can be found in a single rib waveguide without any cavity structure due to the BIC mechanism [21][22][23] .…”

“…For integrated photonics, resonances can be found in a single rib waveguide without any cavity structure due to the BIC mechanism [21][22][23] . In addition, BICs on an integrated photonic platform can be harnessed for realizing low-loss waveguiding by patterning a low-refractiveindex material on a high-refractive-index substrate 14,15,20 . Light guided by the low-refractive-index waveguide can be perfectly confined to the region of high-refractive-index substrate under the low-refractive-index waveguide.…”