More Like this

1. Optomechanical ring resonator for efficient microwave-optical frequency conversion

   https://doi.org/10.1038/s41467-023-43393-x  

   Chen, I-Tung ; Li, Bingzhao ; Lee, Seokhyeong ; Chakravarthi, Srivatsa ; Fu, Kai-Mei ; Li, Mo ( November 2023 , Nature Communications)

   Phonons traveling in solid-state devices are emerging as a universal excitation for coupling different physical systems. Phonons at microwave frequencies have a similar wavelength to optical photons in solids, enabling optomechanical microwave-optical transduction of classical and quantum signals. It becomes conceivable to build optomechanical integrated circuits (OMIC) that guide both photons and phonons and interconnect photonic and phononic devices. Here, we demonstrate an OMIC including an optomechanical ring resonator (OMR), where  co-resonant infrared photons and GHz phonons induce significantly enhanced interconversion. The platform is hybrid, using wide bandgap semiconductor gallium phosphide (GaP) for waveguiding and piezoelectric zinc oxide (ZnO) for phonon generation. The OMR features photonic and phononic quality factors of >1 × 10⁵and 3.2 × 10³, respectively. The optomechanical interconversion between photonic modes achieved an internal conversion efficiency$${\eta }_{i}=(2.1\pm 0.1)\%$$${\eta }_i=\left(2.1\pm 0.1\right)\%$and a total device efficiency$${\eta }_{{tot}}=0.57{\times 10}^{-6}$$${\eta }_{tot}=0.57{\times 10}^{-6}$at a low acoustic pump power of 1.6 mW. The efficient conversion in OMICs enables microwave-optical transduction for quantum information and microwave photonics applications.

    

   more » « less
2. Efficient Collection and Detection of Color Center Emission in Triangular Nanophotonic Geometry of Silicon Carbide

   Pranta Saha ; Sridhar Majety ; Marina Radulaski ( May 2023 , IEEE Explore)

   Angle-etching fabrication produces state-of-the-art color center triangular nanophotonic devices. We uncover how the photonic band gap is formed in the triangular geometry and utilized for efficient detection from SiC waveguide into overlaid NbTiN detectors. 

   more » « less
3. Low-loss fiber-to-chip interface for lithium niobate photonic integrated circuits

   https://doi.org/10.1364/OL.44.002314  

   He, Lingyan ; Zhang, Mian ; Shams-Ansari, Amirhassan ; Zhu, Rongrong ; Wang, Cheng ; Marko, Lončar ( April 2019 , Optics Letters)

   Integrated lithium niobate (LN) photonic circuits have recently emerged as a promising candidate for advanced photonic functions such as high-speed modulation, nonlinear frequency conversion, and frequency comb generation. For practical applications, optical interfaces that feature low fiber-to-chip coupling losses are essential. So far, the fiber-to-chip loss (commonly$>10\mathrm{dB}/\text{facet}$) has dominated the total insertion losses of typical LN photonic integrated circuits, where on-chip losses can be as low as 0.03–0.1 dB/cm. Here we experimentally demonstrate a low-loss mode size converter for coupling between a standard lensed fiber and sub-micrometer LN rib waveguides. The coupler consists of two inverse tapers that convert the small optical mode of a rib waveguide into a symmetrically guided mode of a LN nanowire, featuring a larger mode area matched to that of a tapered optical fiber. The measured fiber-to-chip coupling loss is lower than 1.7 dB/facet with high fabrication tolerance and repeatability. Our results open the door for practical integrated LN photonic circuits efficiently interfaced with optical fibers.

    

   more » « less
4. Heterogeneous integration of superconducting thin films and epitaxial semiconductor heterostructures with lithium niobate

   https://doi.org/10.1088/1361-6463/acd7f9  

   Lienhart, Michelle ; Choquer, Michael ; Nysten, Emeline D. S. ; Weiß, Matthias ; Müller, Kai ; Finley, Jonathan J. ; Moody, Galan ; Krenner, Hubert J. ( June 2023 , Journal of Physics D: Applied Physics)

   We report on scalable heterointegration of superconducting electrodes and epitaxial semiconductor quantum dots (QDs) on strong piezoelectric and optically nonlinear lithium niobate. The implemented processes combine the sputter-deposited thin film superconductor niobium nitride and III–V compound semiconductor membranes onto the host substrate. The superconducting thin film is employed as a zero-resistivity electrode material for a surface acoustic wave resonator with internal quality factors$Q\approx 17000$representing a three-fold enhancement compared to identical devices with normal conducting electrodes. Superconducting operation of$\approx 400\mathrm{M}\mathrm{H}\mathrm{z}$resonators is achieved to temperatures$T>7\mathrm{K}$and electrical radio frequency powers$P_{\mathrm{r}\mathrm{f}}>+9\mathrm{d}\mathrm{B}\mathrm{m}$. Heterogeneously integrated single QDs couple to the resonant phononic field of the surface acoustic wave resonator operated in the superconducting regime. Position and frequency selective coupling mediated by deformation potential coupling is validated using time-integrated and time-resolved optical spectroscopy. Furthermore, acoustoelectric charge state control is achieved in a modified device geometry harnessing large piezoelectric fields inside the resonator. The hybrid QD—surface acoustic wave resonator can be scaled to higher operation frequencies and smaller mode volumes for quantum phase modulation and transduction between photons and phonons via the QD. Finally, the employed materials allow for the realization of other types of optoelectronic devices, including superconducting single photon detectors and integrated photonic and phononic circuits.

    

   more » « less
5. Measurement of the production cross section for a W boson in association with a charm quark in proton–proton collisions at $$\sqrt{s} = 13\,\hbox {TeV}$$

   https://doi.org/10.1140/epjc/s10052-023-12258-4  

   Tumasyan, A ; Adam, W ; Andrejkovic, J W ; Bergauer, T ; Chatterjee, S ; Damanakis, K ; Dragicevic, M ; Valle, A_Escalante Del ; Hussain, P S ; Jeitler, M ; et al ( January 2024 , The European Physical Journal C)

   The strange quark content of the proton is probed through the measurement of the production cross section for a W boson and a charm (c) quark in proton–proton collisions at a center-of-mass energy of 13$$\,\text {Te}\hspace{-.08em}\text {V}$$$\text{Te}\text{V}$. The analysis uses a data sample corresponding to a total integrated luminosity of 138$$\,\text {fb}^{-1}$$${\text{fb}}^{-1}$collected with the CMS detector at the LHC. The W bosons are identified through their leptonic decays to an electron or a muon, and a neutrino. Charm jets are tagged using the presence of a muon or a secondary vertex inside the jet. The$$\hbox {W}+\hbox {c}$$$\text{W}+\text{c}$production cross section and the cross section ratio$$R_\textrm{c}^{\pm }= \sigma ({\hbox {W}}^{+}+\bar{\text {c}})/\sigma (\hbox {W}^{-}+{\textrm{c}})$$$R_{\text{c}}^{\pm }=\sigma ({\text{W}}^{+}+\overline{\text{c}})/\sigma ({\text{W}}^{-}+\text{c})$are measured inclusively and differentially as functions of the transverse momentum and the pseudorapidity of the lepton originating from the W boson decay. The precision of the measurements is improved with respect to previous studies, reaching 1% in$$R_\textrm{c}^{\pm }= 0.950 \pm 0.005\,\text {(stat)} \pm 0.010 \,\text {(syst)} $$$R_{\text{c}}^{\pm }=0.950\pm 0.005\text{(stat)}\pm 0.010\text{(syst)}$. The measurements are compared with theoretical predictions up to next-to-next-to-leading order in perturbative quantum chromodynamics.

    

   more » « less