@article{yu_li_xu_hu_liu_cao_2023, title={Phase Diagram of High-Temperature Electron-Hole Quantum Droplet in Two-Dimensional Semiconductors}, ISSN={["1936-086X"]}, DOI={10.1021/acsnano.3c01365}, abstractNote={Quantum liquids, systems exhibiting effects of quantum mechanics and quantum statistics at macroscopic levels, represent one of the most exciting research frontiers of modern physical science and engineering. Notable examples include Bose-Einstein condensation (BEC), superconductivity, quantum entanglement, and a quantum liquid. However, quantum liquids are usually only stable at cryogenic temperatures, significantly limiting fundamental studies and device development. Here we demonstrate the formation of stable electron-hole liquid (EHL) with the quantum statistic nature at temperatures as high as 700 K in monolayer MoS2 and elucidate that the high-temperature EHL exists as droplets in sizes of around 100-160 nm. We also develop a thermodynamic model of high-temperature EHL and, based on the model, compile an exciton phase diagram, revealing that the ionized photocarrier drives the gas-liquid transition, which is subsequently validated with experimental results. The high-temperature EHL provides a model system to enable opportunities for studies in the pursuit of other high-temperature quantum liquids. The results can also allow for the development of quantum liquid devices with practical applications in quantum information processing, optoelectronics, and optical interconnections.}, journal={ACS NANO}, author={Yu, Yiling and Li, Guoqing and Xu, Yan and Hu, Chong and Liu, Xiaoze and Cao, Linyou}, year={2023}, month={Aug} }
 @article{yu_yu_li_puretzky_geohegan_cao_2020, title={Giant enhancement of exciton diffusivity in two-dimensional semiconductors}, volume={6}, ISSN={["2375-2548"]}, DOI={10.1126/sciadv.abb4823}, abstractNote={The exciton diffusivity of 2D semiconductors can be improved by 15-fold with trapped charges that can screen exciton scattering.}, number={51}, journal={SCIENCE ADVANCES}, author={Yu, Yiling and Yu, Yifei and Li, Guoqing and Puretzky, Alexander A. and Geohegan, David B. and Cao, Linyou}, year={2020}, month={Dec} }
 @article{yu_minhaj_huang_yu_cao_2020, title={In-Plane and Interfacial Thermal Conduction of Two-Dimensional Transition-Metal Dichalcogenides}, volume={13}, ISSN={["2331-7019"]}, DOI={10.1103/PhysRevApplied.13.034059}, abstractNote={We elucidate the dependence of the in-plane and interfacial thermal conduction of two-dimensional (2D) transition-metal dichalcogenide (TMDC) materials (including ${\mathrm{Mo}\mathrm{S}}_{2}$, ${\mathrm{WS}}_{2}$, and ${\mathrm{W}\mathrm{Se}}_{2}$) on the materials' physical features, such as size, layer number, composition, and substrates. The in-plane thermal conductivity k is measured at suspended 2D TMDC materials and the interfacial thermal conductance g is measured at materials supported on substrates, both through Raman thermometry techniques. The thermal conductivity k increases with the radius R of the suspended area following a logarithmic scaling as k\ensuremath{\sim}log(R). k also shows a substantial decrease from monolayer to bilayer, but only changes slightly with a further increase in the layer number. In contrast, the interfacial thermal conductance g has a negligible dependence on the layer number, but g increases with the strength of the interaction between 2D TMDC materials and the substrate, substantially varying among different substrates. The result is consistent with theoretical predictions and clarifies much inconsistence in the literature. This work provides useful guidance for thermal management in 2D TMDC materials and devices.}, number={3}, journal={PHYSICAL REVIEW APPLIED}, author={Yu, Yifei and Minhaj, Tamzid and Huang, Lujun and Yu, Yiling and Cao, Linyou}, year={2020}, month={Mar} }
 @article{datta_chae_bhatt_tadayon_li_yu_park_park_cao_basov_et al._2020, title={Low-loss composite photonic platform based on 2D semiconductor monolayers}, volume={14}, ISSN={["1749-4893"]}, DOI={10.1038/s41566-020-0590-4}, abstractNote={Two dimensional materials such as graphene and transition metal dichalcogenides (TMDs) are promising for optical modulation, detection, and light emission since their material properties can be tuned on-demand via electrostatic doping. The optical properties of TMDs have been shown to change drastically with doping in the wavelength range near the excitonic resonances. However, little is known about the effect of doping on the optical properties of TMDs away from these resonances, where the material is transparent and therefore could be leveraged in photonic circuits. Here, we probe the electro-optic response of monolayer TMDs at near infrared (NIR) wavelengths (i.e. deep in the transparency regime), by integrating them on silicon nitride (SiN) photonic structures to induce strong light$-$matter interaction with the monolayer. We dope the monolayer to carrier densities of ($7.2 \pm 0.8$) $\times$ $10^{13} \textrm{cm}^{-2}$, by electrically gating the TMD using an ionic liquid. We show strong electro-refractive response in monolayer tungsten disulphide (WS$_2$) at NIR wavelengths by measuring a large change in the real part of refractive index $\Delta$n = $0.53$, with only a minimal change in the imaginary part $\Delta$k = $0.004$. The doping induced phase change ($\Delta$n), compared to the induced absorption ($\Delta$k) measured for WS$_2$ ($\Delta$n/$\Delta$k $\sim 125$), a key metric for photonics, is an order of magnitude higher than the $\Delta$n/$\Delta$k for bulk materials like silicon ($\Delta$n/$\Delta$k $\sim 10$), making it ideal for various photonic applications. We further utilize this strong tunable effect to demonstrate an electrostatically gated SiN-WS$_2$ phase modulator using a WS$_2$-HfO$_2$ (Hafnia)-ITO (Indium Tin Oxide) capacitive configuration, that achieves a phase modulation efficiency (V$_\pi$L) of 0.8 V $\cdot$ cm with a RC limited bandwidth of 0.3 GHz.}, number={4}, journal={NATURE PHOTONICS}, author={Datta, Ipshita and Chae, Sang Hoon and Bhatt, Gaurang R. and Tadayon, Mohammad Amin and Li, Baichang and Yu, Yiling and Park, Chibeom and Park, Jiwoong and Cao, Linyou and Basov, D. N. and et al.}, year={2020}, month={Apr}, pages={256-+} }
 @article{yu_bataller_younts_yu_li_puretzky_geohegan_gundogdu_cao_2019, title={Room-Temperature Electron-Hole Liquid in Monolayer MoS2}, volume={13}, ISSN={["1936-086X"]}, DOI={10.1021/acsnano.9b04124}, abstractNote={Excitons in semiconductors are usually non-interacting and behave like an ideal gas, but may condense to a strongly-correlated liquid-like state, i.e. electron-hole liquid (EHL), at high density and appropriate temperature. EHL is a macroscopic quantum state with exotic properties and represents the ultimate attainable charge excitation density in steady states. It bears great promise for a variety of fields such as ultrahigh-power photonics and quantum science and technology. However, the condensation of gas-like excitons to EHL has often been restricted to cryogenic temperatures, which significantly limits the prospect of EHL for use in practical applications. Herein we demonstrate the formation of EHL at room temperature in monolayer MoS2 by taking advantage of the monolayer's extraordinarily strong exciton binding energy. This work demonstrates the potential for the liquid-like state of charge excitations to be a useful platform for the studies of macroscopic quantum phenomena and the development of optoelectronic devices.}, number={9}, journal={ACS NANO}, author={Yu, Yiling and Bataller, Alexander W. and Younts, Robert and Yu, Yifei and Li, Guoqing and Puretzky, Alexander A. and Geohegan, David B. and Gundogdu, Kenan and Cao, Linyou}, year={2019}, month={Sep}, pages={10351–10358} }
 @article{su_bradley_yu_yu_cao_zhao_zhang_2019, title={Surface-enhanced Raman scattering of monolayer transition metal dichalcogenides on Ag nanorod arrays}, volume={44}, ISSN={["1539-4794"]}, DOI={10.1364/OL.44.005493}, abstractNote={In this work, we studied surface-enhanced Raman scattering (SERS) of MS2 (M=Mo, W) monolayers that were transferred onto Ag nanorod arrays. Compared to the suspended monolayers, the Raman intensity of monolayers on an Ag nanorod substrate was strongly enhanced for both in-plane and out-of-plane vibration modes: up to 8 (5) for E2g and 20 (23) for A1g in MoS2 (WS2). This finding reveals a promising SERS substrate for achieving uniform and strong enhancement for two-dimensional materials in the applications of optical detecting and sensing.}, number={22}, journal={OPTICS LETTERS}, author={Su, Liqin and Bradley, Layne and Yu, Yiling and Yu, Yifei and Cao, Linyou and Zhao, Yiping and Zhang, Yong}, year={2019}, month={Nov}, pages={5493–5496} }
 @article{yu_li_huang_barrette_cai_yu_gundogdu_zhang_cao_2017, title={Enhancing Multifunctionalities of Transition-Metal Dichalcogenide Monolayers via Cation Intercalation}, volume={11}, ISSN={1936-0851 1936-086X}, url={http://dx.doi.org/10.1021/ACSNANO.7B04880}, DOI={10.1021/acsnano.7b04880}, abstractNote={We have demonstrated that multiple functionalities of transition-metal dichalcogenide (TMDC) monolayers may be substantially improved by the intercalation of small cations (H+ or Li+) between the monolayers and underlying substrates. The functionalities include photoluminescence (PL) efficiency and catalytic activity. The improvement in PL efficiency may be up to orders of magnitude and can be mainly ascribed to two effects of the intercalated cations: p-doping to the monolayers and reducing the influence of substrates, but more studies are necessary to better understand the mechanism for the improvement in the catalytic functionality. The cation intercalation may be achieved by simply immersing substrate-supported monolayers into the solution of certain acids or salts. It is more difficult to intercalate under the monolayers interacting with substrates stronger, such as as-grown monolayers or the monolayers on 2D material substrates. This result presents a versatile strategy to simultaneously optimize multiple functionalities of TMDC monolayers.}, number={9}, journal={ACS Nano}, publisher={American Chemical Society (ACS)}, author={Yu, Yifei and Li, Guoqing and Huang, Lujun and Barrette, Andrew and Cai, Yong-Qing and Yu, Yiling and Gundogdu, Kenan and Zhang, Yong-Wei and Cao, Linyou}, year={2017}, month={Sep}, pages={9390–9396} }
 @article{yu_yu_huang_peng_xiong_cao_2017, title={Giant Gating Tunability of Optical Refractive Index in Transition Metal Dichalcogenide Monolayers}, volume={17}, ISSN={["1530-6992"]}, DOI={10.1021/acs.nanolett.7b00768}, abstractNote={We report that the refractive index of transition metal dichacolgenide (TMDC) monolayers, such as MoS2, WS2, and WSe2, can be substantially tuned by >60% in the imaginary part and >20% in the real part around exciton resonances using complementary metal-oxide-semiconductor (CMOS) compatible electrical gating. This giant tunablility is rooted in the dominance of excitonic effects in the refractive index of the monolayers and the strong susceptibility of the excitons to the influence of injected charge carriers. The tunability mainly results from the effects of injected charge carriers to broaden the spectral width of excitonic interband transitions and to facilitate the interconversion of neutral and charged excitons. The other effects of the injected charge carriers, such as renormalizing bandgap and changing exciton binding energy, only play negligible roles. We also demonstrate that the atomically thin monolayers, when combined with photonic structures, can enable the efficiencies of optical absorption (reflection) tuned from 40% (60%) to 80% (20%) due to the giant tunability of the refractive index. This work may pave the way toward the development of field-effect photonics in which the optical functionality can be controlled with CMOS circuits.}, number={6}, journal={NANO LETTERS}, author={Yu, Yiling and Yu, Yifei and Huang, Lujun and Peng, Haowei and Xiong, Liwei and Cao, Linyou}, year={2017}, month={Jun}, pages={3613–3618} }
 @article{huang_li_gurarslan_yu_kirste_guo_zhao_collazo_sitar_parsons_et al._2016, title={Atomically Thin MoS2 Narrowband and Broadband Light Superabsorbers}, volume={10}, ISSN={["1936-086X"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000381959100030&KeyUID=WOS:000381959100030}, DOI={10.1021/acsnano.6b02195}, abstractNote={We present a combined theoretical and experimental effort to enable strong light absorption (>70%) in atomically thin MoS2 films (≤4 layers) for either narrowband incidence with arbitrarily prespecified wavelengths or broadband incidence like solar radiation. This is achieved by integrating the films with resonant photonic structures that are deterministically designed using a unique reverse design approach based on leaky mode coupling. The design starts with identifying the properties of leaky modes necessary for the targeted strong absorption, followed by searching for the geometrical features of nanostructures to support the desired modes. This process is very intuitive and only involves a minimal amount of computation, thanks to the straightforward correlations between optical functionality and leaky modes as well as between leaky modes and the geometrical feature of nanostructures. The result may provide useful guidance for the development of high-performance atomic-scale photonic devices, such as solar cells, modulators, photodetectors, and photocatalysts.}, number={8}, journal={ACS NANO}, author={Huang, Lujun and Li, Guoqing and Gurarslan, Alper and Yu, Yiling and Kirste, Ronny and Guo, Wei and Zhao, Junjie and Collazo, Ramon and Sitar, Zlatko and Parsons, Gregory N. and et al.}, year={2016}, month={Aug}, pages={7493–7499} }
 @article{yu_yu_xu_cai_su_zhang_zhang_gundogdu_cao_2016, title={Engineering Substrate Interactions for High Luminescence Efficiency of Transition-Metal Dichalcogenide Monolayers}, volume={26}, ISSN={["1616-3028"]}, DOI={10.1002/adfm.201600418}, abstractNote={It is demonstrated that the luminescence efficiency of monolayers composed of MoS2, WS2, and WSe2 is significantly limited by the substrate and can be improved by orders of magnitude through substrate engineering. The substrate affects the efficiency mainly through doping the monolayers and facilitating defect‐assisted nonradiative exciton recombinations, while the other substrate effects including straining and dielectric screening play minor roles. The doping may come from the substrate and substrate‐borne water moisture, the latter of which is much stronger than the former for MoS2 and WS2 but negligible for WSe2. Using proper substrates such as mica or hexagonal boron nitride can substantially mitigate the doping effect. The defect‐assisted recombination depends on the interaction between the defect in the monolayer and the substrate. Suspended monolayers, in which the substrate effects are eliminated, may have efficiency up to 40% at room temperatures. The result provides useful guidance for the rational design of atomic‐scale light emission devices.}, number={26}, journal={ADVANCED FUNCTIONAL MATERIALS}, author={Yu, Yifei and Yu, Yiling and Xu, Chao and Cai, Yong-Qing and Su, Liqin and Zhang, Yong and Zhang, Yong-Wei and Gundogdu, Kenan and Cao, Linyou}, year={2016}, month={Jul}, pages={4733–4739} }
 @article{yu_yu_xu_barrette_gundogdu_cao_2016, title={Fundamental limits of exciton-exciton annihilation for light emission in transition metal dichalcogenide monolayers}, volume={93}, DOI={10.1103/physrevb.93.201111}, abstractNote={We quantitatively evaluate the exciton-exciton annihilation (EEA) and its effect on light emission properties in monolayer TMDC materials, including WS2, MoS2, and WSe2. The EEA rate is found to be 0.3 cm2/s and 0.1 cm2/s for suspended WS2 and MoS2 monolayers, respectively, and subject to the influence from substrates, being 0.1 cm2/s and 0.05 cm2/s for the supported WS2 and MoS2 on sapphire substrates. It can substantially affect the luminescence efficiency of suspended monolayers even at an exciton concentration as low as 109 cm-2, but plays a milder role for supported monolayers due to the effect of the substrate. However, regardless the presence of substrates or not, the lasing threshold of the monolayer is always predominantly determined by the EEA, which is estimated to be 12-18 MW/cm2 if using 532 nm as the pumping wavelength.}, number={20}, journal={Physical Review B}, author={Yu, Y. L. and Yu, Y. F. and Xu, C. and Barrette, A. and gundogdu and Cao, L. Y.}, year={2016} }
 @article{gurarslan_jiao_li_li_yu_gao_riedo_xu_cao_2016, title={Van der Waals Force Isolation of Monolayer MoS2}, volume={28}, ISSN={["1521-4095"]}, DOI={10.1002/adma.201601581}, abstractNote={Monolayer MoS2 can effectively screen the vdW interaction of underlying substrates with external systems by >90% because of the substantial increase in the separation between the substrate and external systems due to the presence of the monolayer. This substantial screening of vdW interactions by MoS2 monolayer is different from what reported at graphene.}, number={45}, journal={ADVANCED MATERIALS}, author={Gurarslan, Alper and Jiao, Shuping and Li, Tai-De and Li, Guoqing and Yu, Yiling and Gao, Yang and Riedo, Elisa and Xu, Zhiping and Cao, Linyou}, year={2016}, month={Dec}, pages={10055–10060} }
 @article{lin_huang_yu_he_cao_2015, title={Deterministic phase engineering for optical Fano resonances with arbitrary lineshape and frequencies}, volume={23}, ISSN={["1094-4087"]}, DOI={10.1364/oe.23.019154}, abstractNote={We present an approach of deterministic phase engineering that can enable the rational design of optical Fano resonances with arbitrarily pre-specified lineshapes. Unlike all the approaches previously used to design optical Fano resonances, which fall short of designing the resonances with arbitrary lineshapes because of the lack of information for the optical phases involved, we develop our approach by capitalizing on unambiguous knowledge for the phase of optical modes. Optical Fano resonances arise from the interference of photons interacting with two optical modes with substantially different quality factors. We find that the phase difference of the two modes involved in optical Fano resonances is determined by the eigenfrequency difference of the modes. This allows us to deterministically engineer the phase by tuning the eigenfrequency, which may be very straightforward. We use dielectric grating structures as an example to illustrate the notion of deterministic engineering for the design of optical Fano resonances with arbitrarily pre-specified symmetry, linewidth, and wavelengths.}, number={15}, journal={OPTICS EXPRESS}, author={Lin, Jiao and Huang, Lujun and Yu, Yiling and He, Sailing and Cao, Linyou}, year={2015}, month={Jul}, pages={19154–19165} }
 @article{yu_yu_cai_li_gurarslan_peelaers_aspnes_walle_nguyen_zhang_et al._2015, title={Exciton-dominated Dielectric Function of Atomically Thin MoS2 Films}, volume={5}, ISSN={["2045-2322"]}, DOI={10.1038/srep16996}, abstractNote={Abstract}, journal={SCIENTIFIC REPORTS}, author={Yu, Yiling and Yu, Yifei and Cai, Yongqing and Li, Wei and Gurarslan, Alper and Peelaers, Hartwin and Aspnes, David E. and Walle, Chris G. and Nguyen, Nhan V. and Zhang, Yong-Wei and et al.}, year={2015}, month={Nov} }
 @article{yu_cao_2014, title={Leaky mode engineering: A general design principle for dielectric optical antenna solar absorbers}, volume={314}, ISSN={0030-4018}, url={http://dx.doi.org/10.1016/j.optcom.2013.10.051}, DOI={10.1016/j.optcom.2013.10.051}, abstractNote={We present a general principle for the rational design of dielectric optical antennas with optimal solar absorption enhancement: leaky mode engineering. This builds upon our previous study that demonstrates the solar absorption of a material with a given volume only dependent on the density and the radiative loss of leaky modes of the material. Here we systematically examine the correlation among the modal properties (density and radiative loss) of leaky modes, physical features, and solar absorption of dielectric antenna structures. Our analysis clearly points out the general guidelines for the design of dielectric optical antennas with optimal solar absorption enhancement: (a) using 0D structures; (b) the shape does not matter much; (c) heterostructuring with non-absorbing materials is a promising strategy; and (d) the design of a large-scale nanostructure array can use the solar absorption of single nanostructures as a reasonable reference.}, journal={Optics Communications}, publisher={Elsevier BV}, author={Yu, Yiling and Cao, Linyou}, year={2014}, month={Mar}, pages={79–85} }
 @article{yu_huang_cao_2014, title={Semiconductor Solar Superabsorbers}, volume={4}, ISSN={["2045-2322"]}, DOI={10.1038/srep04107}, abstractNote={Understanding the maximal enhancement of solar absorption in semiconductor materials by light trapping promises the development of affordable solar cells. However, the conventional Lambertian limit is only valid for idealized material systems with weak absorption and cannot hold for the typical semiconductor materials used in solar cells due to the substantial absorption of these materials. Herein we theoretically demonstrate the maximal solar absorption enhancement for semiconductor materials and elucidate the general design principle for light trapping structures to approach the theoretical maximum. By following the principles, we design a practical light trapping structure that can enable an ultrathin layer of semiconductor materials, for instance, 10 nm thick a-Si, absorb > 90% sunlight above the bandgap. The design has active materials with one order of magnitude less volume than any of the existing solar light trapping designs in literature. This work points towards the development of ultimate solar light trapping techniques.}, journal={SCIENTIFIC REPORTS}, author={Yu, Yiling and Huang, Lujun and Cao, Linyou}, year={2014}, month={Feb} }
 @article{gurarslan_yu_su_yu_suarez_yao_zhu_ozturk_zhang_cao_2014, title={Surface-Energy-Assisted Perfect Transfer of Centimeter-Scale Mono layer and Few-Layer MoS2 Films onto Arbitrary Substrates}, volume={8}, ISSN={["1936-086X"]}, DOI={10.1021/nn5057673}, abstractNote={The transfer of synthesized 2D MoS2 films is important for fundamental and applied research. However, it is problematic to translate the well-established transfer processes for graphene to MoS2 due to different growth mechanisms and surface properties. Here we demonstrate a surface-energy-assisted process that can perfectly transfer centimeter-scale monolayer and few-layer MoS2 films from original growth substrates onto arbitrary substrates with no observable wrinkles, cracks, and polymer residues. The unique strategies used in this process include leveraging the penetration of water between hydrophobic MoS2 films and hydrophilic growth substrates to lift off the films and dry transferring the film after the lift off. This is in stark contrast with the previous transfer process for synthesized MoS2 films, which explores the etching of the growth substrate by hot base solutions to lift off the films. Our transfer process can effectively eliminate the mechanical force caused by bubble generations, the attacks from chemical etchants, and the capillary force induced when transferring the film outside solutions as in the previous transfer process, which consists of the major causes for the previous unsatisfactory transfer. Our transfer process also benefits from using polystyrene (PS), instead of poly(methyl methacrylate) (PMMA) that was widely used previously, as the carrier polymer. PS can form more intimate interaction with MoS2 films than PMMA and is important for maintaining the integrity of the film during the transfer process. This surface-energy-assisted approach can be generally applied to the transfer of other 2D materials, such as WS2.}, number={11}, journal={ACS NANO}, author={Gurarslan, Alper and Yu, Yifei and Su, Liqin and Yu, Yiling and Suarez, Francisco and Yao, Shanshan and Zhu, Yong and Ozturk, Mehmet and Zhang, Yong and Cao, Linyou}, year={2014}, month={Nov}, pages={11522–11528} }
 @article{huang_yu_cao_2013, title={General Modal Properties of Optical Resonances in Subwavelength Nonspherical Dielectric Structures}, volume={13}, ISSN={["1530-6992"]}, DOI={10.1021/nl401150j}, abstractNote={Subwavelength dielectric structures offer an attractive low-loss alternative to plasmonic materials for the development of resonant optics functionalities such as metamaterials and optical antennas. Nonspherical-like rectangular dielectric structures are of the most interest from the standpoint of device development due to fabrication convenience. However, no intuitive fundamental understanding of the optical resonance in nonspherical dielectric structures is available, which has substantially delayed the development of dielectric resonant optics devices. Here, we elucidate the general fundamentals of the optical resonance in nonspherical subwavelength dielectric structures with different shapes (rectangular or triangular) and dimensionalities (1D nanowires or 0D nanoparticles). We demonstrate that the optical properties of nonspherical dielectric structures are dictated by the eigenvalue of the structure's leaky modes. Leaky modes are defined as optical modes with propagating waves outside the structure. We also elucidate the dependence of the modal eigenvalue on physical features of the structure. The eigenvalue shows scale invariance with respect to the size of the structure, weak dependence on the refractive index, but linear dependence on the size ratio of different sides of the structure. We propose a modified Fabry-Perot model to account for the linear dependence. The knowledge of leaky modes, including the role in optical responses and the dependence on physical features, can serve as a powerful guide for the rational design of devices with desired optical resonances. It may open up a pathway to design devices with functionality that has not been explored due to the lack of intuitive understanding, for instance, imaging devices able to sense incident angle or superabsorbing photodetectors.}, number={8}, journal={NANO LETTERS}, author={Huang, Lujun and Yu, Yiling and Cao, Linyou}, year={2013}, month={Aug}, pages={3559–3565} }
 @article{yu_cao_2013, title={The phase shift of light scattering at sub-wavelength dielectric structures}, volume={21}, ISSN={["1094-4087"]}, DOI={10.1364/oe.21.005957}, abstractNote={We present a new theoretical analysis for the light scattering at sub-wavelength dielectric structures. This analysis can provide new intuitive insights into the phase shift of the scattered light that cannot be obtained from the existing approaches. Unlike the traditional analytical (e.g. Mie formalism) and numerical (e.g. FDTD) approaches, which simulate light scattering by rigorously matching electromagnetic fields at boundaries, we consider sub-wavelength dielectric structures as leaky resonators and evaluate the light scattering as a coupling process between incident light and leaky modes of the structure. Our analysis indicates that the light scattering is fundamentally dictated by the eigenvalue of the leaky modes. It indicates that the upper limit for the scattering efficiency of a cylindrical cylinder in free space is 4n, where n is the refractive index. It also indicates that the phase shift of the forward scattered light at dielectric structures can only cover half of the phase space [0, 2π], but backward scattering can provide a full phase coverage.}, number={5}, journal={OPTICS EXPRESS}, author={Yu, Yiling and Cao, Linyou}, year={2013}, month={Mar}, pages={5957–5967} }