Realization of an Electrically Tunable Narrow-Bandwidth Atomically Thin Mirror Using MonolayerMoSe2

Abstract

Advent of new materials such as van der Waals heterostructures, propels new research directions in condensed matter physics and enables development of novel devices with unique functionalities. Here, we show experimentally that a monolayer of MoSe 2 embedded in a charge controlled heterostructure can be used to realize an electrically tunable atomically-thin mirror, that effects 90% extinction of an incident field that is resonant with its exciton transition. The corresponding maximum reflection coefficient of 45% is only limited by the ratio of the radiative decay rate to the linewidth of exciton transition and is independent of incident light intensity up to 400 Watts/cm 2 . We demonstrate that the reflectivity of the mirror can be drastically modified by applying a gate voltage that modifies the monolayer charge density. Our findings could find applications ranging from fast programmable spatial light modulators to suspended ultra-light mirrors for optomechanical devices.A plethora of ground-breaking experiments have established monolayers of transition metal dichalcogenides (TMD) such as MoSe 2 or WSe 2 as a new class of two dimensional (2D) direct 1

Near-Unity Light Absorption in a Monolayer WS2 Van der Waals Heterostructure Cavity

“…For very small γ T , γ r,0 dominates the linewidth and the absorption decreases as the TMD becomes highly reflective (corresponding to negative absorption, as seen in (Fig. 2b)) [43][44][45] . For very large γ T , γ nr and γ d dominates the linewidth and the absorption is decreased as the TMD becomes transparent.…”

Cavity Quantum Electrodynamics with Frequency-Dependent Reflectors

“…Photonic crystal membranes received attention lately as a possible platform for quantum OM [29][30][31][32][33][34][35][36]; we show how the effects that may arise owing to their frequency-dependent reflectivity can be rigorously described quantum mechanically. Our results can furthermore be applied to other platforms as well, such as arrays of trapped atoms [12,13,37,38] or semiconductor membranes [10,11,39].…”

“…1). In two-dimensional systems, these effects can be achieved by patterning a subwavelength grating or a photonic-crystal structure onto a dielectric membrane [5][6][7][8]; other systems can be formed by semiconducting monolayers [9][10][11] or two-dimensional arrays of atoms trapped in optical lattices [12][13][14]. Using such metamaterials with a strongly frequency-dependent response as end-mirrors in Fabry-Pérot resonators has been shown to result in asymmetric transmission profiles potentially much narrower than those obtained with frequency-independent mirrors of comparable reflectivity [15] (Fig.…”

Filtering the photoluminescence spectra of atomically thin semiconductors with graphene

“…As a result, X 0 and X emission dominate the PL spectrum of Mo-based TMDs [9], whereas the emission spectra of W-based TMDs display a complex series of lines stemming from X 0 , bi-excitons (XX 0 )[12-15], charged excitonic states (including X [10,16] and charged biexcitons (XX ) [12][13][14][15]), spin-dark excitons [17][18][19], defectinduced emission and exciton-phonon sidebands [20].Considerable progress has been made to determin-istically observe intrinsic TMD emission features. In particular, encapsulation of TMDs in hexagonal boron nitride (BN) films results in narrower neutral exciton linewidth [21,22], approaching the radiative limit [6,23,24], without however, getting rid of the other emission features mentioned above. Even in electrostatically gated devices tuned near the charge neutrality point, sizeable emission sidebands remain observable at energies close to the X feature, suggesting residual charge inhomogeneity [9,10] or intrinsic contributions from longer-lived exciton-phonon replicas [20].The complex emission spectra of TMD stimulate lively scientific debates.…”