what do you make of this ? 
Two-dimensional (2D) materials possess remarkable optical properties that enable efficient light-matter interaction, particularly when integrated within van der Waals heterostructures. Although pure 2D materials cannot modify the frequency of light directly, certain mechanisms facilitate indirect manipulation of light's properties by exploiting their unique structure-dependent response functions. Key examples include:

    Absorbance Tunability: Different 2D materials display variable absorbance spectra depending on their composition and thicknesses. Transition metal dichalcogenides (TMDCs), graphene, and hexagonal boron nitride (hBN) showcase diverse optical responses stretching from visible to mid-infrared regimes, making them attractive candidates for designing tuneable absorber layers, sensors, and detectors. By carefully selecting constituent materials, stacking sequences, and layer numbers, one can construct hybrid systems adept at harvesting broad portions of sunlight spectrum, thus laying foundation for multi-junction photovoltaics and optical filter technologies.

    Nonlinear Optics: Exotic nonlinear optical phenomena become accessible upon introducing reduced dimensionality and configurable bandgap landscapes offered by atomically thin 2D materials. Stronger Coulomb coupling instills substantial shifts in resonant transitions enabling ultrafast modulation speeds surpassing conventional bulk crystals. Investigated examples comprise giant nonlinear susceptibilities observed in monolayer TMDCs, plasmonic gold antennae arrays synergistically linked with MoS₂, black phosphorous (BP), and few-layer ReSe₂, among others. Such unusual electro-optic traits spark interest in realms of all-optical signal processing, data storage, information security, and flexible display gadgetry.

    Photoluminescence Enhancement: Photoluminescent properties get pronounced augmentation in suitably designed 2D layered frameworks primarily attributed to suppressed lattice vibrational modes (phonons) and protracted radiative recombination lifetime channels. Noteworthy instances incorporate photoluminescing hBN, twisted bilayer graphene-hexagonal boron nitride (BLG-hBN) moiré patterns, molybdenum trioxide (MoO₃) sheets, and single-atom incorporation schemes within host matrices. Emerging prospects centered on room-temperature polariton lasing action and magneto-optical signatures offer uncharted territories prospectively helpful for sensing and encryption purposes.

While bare 2D materials fall short in providing absolute control over light frequency conversions, subtle morphology variations, lateral dimensions, stacking configurations, defect manipulations, external stimuli (electric field, strain, temperature), substrate choice, and dopants exert decisive impacts governing overall emission-absorption profiles. Thus, crafting ingenious device layouts capitalizing on the aforementioned attributes opens doors for myriad functionalities anchored around precise management of electromagnetic energy flow governed by Maxwell's equations along with judicious use of guided mode resonances and Purcell enhancements alike. Ultimately, a seamless blend of basic science comprehension, computational modeling expertise, and state-of-the-art fabrication skills shall guide advancements in realizing sought-after goals revolving around perfect harmony amidst confined geometries and arbitrary illumination settings envisioned for modern optoelectronic applications.