Polariton logic

Leistungen

Demonstrate a polariton universal logic gate

Demonstrate a polariton universal logic gate by means of ultrafast optical spectroscopy utilising non-ground state polariton condensation:We will investigate the conditions under which we can realise non-ground state polariton condensation in perovskite/organic microcavities and utilise it to configure the NOR gate.

Fabricated passive sub-components

The fabrication process and the technology platform to realize single nanophotonic devices for the vertical as well as for the in-plane architecture will be described in D3.2 together withfirst optical characterization results of the sub-components. The experimental results are compared with the simulated predictions and thus feedback will be given to all simulation groups to include fabrication limits into the design work.

Report on synthesis of 2D perovskite NPLs and their post synthetic treatments

Report on synthesis of 2D perovskite NPLs and their post synthetic treatments a combined treatment with didodecyldimethylammonium bromide DDAB and lead bromide PbBr2 to efficiently heal the surface trap states and improve the stability developed

Report on development of thin film of two-dimensional layered perovskites

Report on development of thin film of twodimensional layered perovskites 2D perovskite crystals synthesize using an antisolvent vaporassisted crystallization method structural and optical properties reported

Report on Assessment of excitonic properties by optical spectroscopy and theoretical methods

Final report summarizing the main results obtained during the project and that can be made public on the optical characterization and theoretical description of the excitonic properties of the compounds investigated during the project

Report on final PEDR, press release

Report on the final Plan for the Exploitation and Dissemination of Results that summarises the concrete actions related to the protection dissemination and exploitation of the project results including press release

Report on integrated polariton logic and circuit's

The integration of the optical subcomponents to functional complex photonic circuits will be shown In addition this report will describe the final technology to hybridize the integrated optical components with activepolaritonic materials The fabrication process for the integrated polaritonic cuircuits will be described including the optical characterization The experimental performance analysis of POLLOCs polaritonic platforms will be reported

Report on synthesis of ultra-small, optically stable QDs

Report on synthesis of ultrasmall optically stable QDs direct colloidal synthesis of small QDs together with a sizeselective precipitation of zwitterioniccapped QDs reported

Data Management Plan

Plan for Data managementThe team will collect structural and chemical characterisation data In addition raw experimental data from optical characterisation and measurements will be collected and storedEach partner is the owner of the data generated by its employees in the course of the project The protection and access right to data will be managed within the legal framework set out within the Consortium agreement The objective of the project is to publish as many results as possible not restricted to confidentiality to make sure the most essential data are available to the public

Report on polariton amplification:

Report on polariton amplificationOptical measurements to test and validate polariton amplification in perovskite microcavity structures The report will include1 dependence of polariton amplification on excitation wavelength nonresonant and quasiresonant with exciton reservoir2 dependence on pulse duration using fs ps and ns excitation pulses3 Amplified spontaneous emission characterisation of bare films

Report on polariton non-linear interactions in PVSK cavities

Report on polariton non-linear interactions in PVSK cavities:We will report on the energy renormalisation of the lower polariton mode vs excitation density. Complementary measurements will include ASE and z-scan on bare films. The report will quantify the direct (exchange interaction driven) and indirect (rabi-quenching and refractive index renormalisation) of non-linearities in perovskite microcavities.

Project website

Setup of the Project website in its initial form the project website will be updated over the duration of the project by the participants

Veröffentlichungen

Chirality versus Symmetry: Electron’s Spin Selectivity in Non-Polar Chiral Lead-Bromide Perovskites

Autoren: Alexandre Abhervé, Nicolas Mercier, Anil Kumar, Tapan Kumar Das, Jacky Even, Claudine Katan, Mikaël Kepenekian
Veröffentlicht in: Advanced Materials, 2023, Seite(n) 2305784, ISSN 0935-9648
Herausgeber: United Nations Industrial Developement Organization
DOI: 10.1002/adma.202305784

Quantifying Photoinduced Polaronic Distortions in Inorganic Lead Halide Perovskite Nanocrystals

Autoren: Oliviero Cannelli, Nicola Colonna, Michele Puppin, Thomas C. Rossi, Dominik Kinschel, Ludmila M. D. Leroy, Janina Löffler, James M. Budarz, Anne Marie March, Gilles Doumy, Andre Al Haddad, Ming-Feng Tu, Yoshiaki Kumagai, Donald Walko, Grigory Smolentsev, Franziska Krieg, Simon C. Boehme, Maksym V. Kovalenko, Majed Chergui, Giulia F. Mancini
Veröffentlicht in: Journal of the American Chemical Society, Ausgabe 143/24, 2021, Seite(n) 9048-9059, ISSN 0002-7863
Herausgeber: American Chemical Society
DOI: 10.1021/jacs.1c02403

Atomic-Level Description of Thermal Fluctuations in Inorganic Lead Halide Perovskites

Autoren: Oliviero Cannelli; Julia Wiktor; Nicola Colonna; Ludmila Leroy; Michele Puppin; Camila Bacellar; Ilia Sadykov; Franziska Krieg; Grigory Smolentsev; Maksym V. Kovalenko; Alfredo Pasquarello; Majed Chergui; Giulia F. Mancini
Veröffentlicht in: The Journal of Physical Chemistry Letters, 13 (15), Ausgabe 9, 2022, ISSN 1948-7185
Herausgeber: American Chemical Society
DOI: 10.1021/acs.jpclett.2c00281

Anharmonic electron-phonon coupling in ultrasoft and locally disordered perovskites

Autoren: Marios Zacharias, George Volonakis, Feliciano Giustino, Jacky Even
Veröffentlicht in: npj Comput Mater, 2023, ISSN 2057-3960
Herausgeber: Springer Nature
DOI: 10.1038/s41524-023-01089-2

Growth and Self-Assembly of CsPbBr3 Nanocrystals in the TOPO/PbBr2 Synthesis as Seen with X-ray Scattering

Autoren: Federico Montanarella*, Quinten A. Akkerman, Dennis Bonatz, Maaike M. van der Sluijs, Johanna C. van der Bok, P. Tim Prins, Marcel Aebli, Alf Mews, Daniel Vanmaekelbergh, and Maksym V. Kovalenko
Veröffentlicht in: Nano Letters, 23 (2), Ausgabe 19, 2023, ISSN 1530-6992
Herausgeber: American Chemical Society
DOI: 10.1021/acs.nanolett.2c04532

Polariton spin jets through optical control

Autoren: L. Pickup, J. D. Töpfer, H. Sigurdsson, P. G. Lagoudakis
Veröffentlicht in: Physical Review B, Ausgabe 103/15, 2021, ISSN 2469-9950
Herausgeber: APS
DOI: 10.1103/physrevb.103.155302

Photonic Berry curvature in double liquid crystal microcavities with broken inversion symmetry

Autoren: P. Kokhanchik, H. Sigurdsson, B. Piętka, J. Szczytko, and P. G. Lagoudakis
Veröffentlicht in: Phys. Rev. B, Ausgabe 103, L081406, 2021, ISSN 2469-9969
Herausgeber: APS
DOI: 10.1103/physrevb.103.l081406

Exciton ground state fine structure and excited states landscape in layered halide perovskites from combined BSE simulations and symmetry analysis

Autoren: Claudio Quarti, Giacomo Giorgi, Claudine Katan, Jacky Even, Maurizia Palummo
Veröffentlicht in: Advanced Optical Materials, 2023, ISSN 2195-1071
Herausgeber: Wiley
DOI: 10.1002/adom.202202801

Directional planar antennae in polariton condensates

Autoren: Denis Aristov; Stepan Baryshev; Julian D. Töpfer; Helgi Sigurðsson; Pavlos G. Lagoudakis
Veröffentlicht in: Applied Physics Letters, Ausgabe 123, 121101, 2023, ISSN 0003-6951
Herausgeber: American Institute of Physics
DOI: 10.1063/5.0159665

Strongly Confined CsPbBr<sub>3</sub> Quantum Dots as Quantum Emitters and Building Blocks for Rhombic Superlattices

Autoren: Simon C. Boehme; Maryna I. Bodnarchuk; Max Burian; Federica Bertolotti; Ihor Cherniukh; Caterina Bernasconi; Chenglian Zhu; Rolf Erni; Heinz Amenitsch; Denys Naumenko; Hordii Andrusiv; Nazar Semkiv; Rohit Abraham John; Alan Baldwin; Krzysztof Galkowski; Norberto Masciocchi; Samuel D. Stranks; Gabriele Rainò; Antonietta Guagliardi; Maksym V. Kovalenko
Veröffentlicht in: ACS Nano, 17 (3), Ausgabe 23, 2023, ISSN 1936-086X
Herausgeber: ACS
DOI: 10.1021/acsnano.2c07677

Many-body Correlations and Exciton Complexes in CsPbBr3 Quantum Dots

Autoren: Chenglian Zhu, Tan Nguyen, Simon C. Boehme, Anastasiia Moskalenko, Dmitry N. Dirin, Maryna I. Bodnarchuk, Claudine Katan, Jacky Even, Gabriele Rainò, Maksym V. Kovalenko
Veröffentlicht in: Advanced Materials, 2022, Seite(n) 2208354, ISSN 0935-9648
Herausgeber: United Nations Industrial Developement Organization
DOI: 10.1002/adma.202208354

"Quantum vortex formation in the ""rotating bucket"" experiment with polariton condensates"

Autoren: Gnusov, Ivan; Harrison, Stella; Alyatkin, Sergey; Sitnik, Kirill; Toepfer, Julian; Sigurdsson, Helgi; Lagoudakis, Pavlos
Veröffentlicht in: Science Advances, Ausgabe 9/04/eadd1299, 2023, ISSN 2375-2548
Herausgeber: American Association for the Advancement of Science
DOI: 10.1126/sciadv.add1299

Perovskite Quantum Dots for Super‐Resolution Optical Microscopy: Where Strong Photoluminescence Blinking Matters

Autoren: Leon G. Feld, Yevhen Shynkarenko, Franziska Krieg, Gabriele Rainò, Maksym V. Kovalenko
Veröffentlicht in: Advanced Optical Materials, Ausgabe 9/18, 2021, Seite(n) 2100620, ISSN 2195-1071
Herausgeber: Advanced optical materials (Wiley)
DOI: 10.1002/adom.202100620

Room-Temperature, Highly Pure Single-Photon Sources from All-Inorganic Lead Halide Perovskite Quantum Dots

Autoren: Chenglian Zhu; Malwina Marczak; Leon Feld; Simon C. Boehme; Caterina Bernasconi; Anastasiia Moskalenko; Ihor Cherniukh; Dmitry Dirin; Maryna I. Bodnarchuk; Maksym V. Kovalenko; Gabriele Rainò
Veröffentlicht in: Nano Letters, 22 (9), Ausgabe 9, 2022, ISSN 1530-6984
Herausgeber: American Chemical Society
DOI: 10.3929/ethz-b-000544023

Single-photon nonlinearity at room temperature

Autoren: Anton V. Zasedatelev, Anton V. Baranikov, Denis Sannikov, Darius Urbonas, Fabio Scafirimuto, Vladislav Yu. Shishkov, Evgeny S. Andrianov, Yurii E. Lozovik, Ullrich Scherf, Thilo Stöferle, Rainer F. Mahrt, Pavlos G. Lagoudakis
Veröffentlicht in: Nature, Ausgabe 597/7877, 2021, Seite(n) 493-497, ISSN 0028-0836
Herausgeber: Nature Publishing Group
DOI: 10.1038/s41586-021-03866-9

Realizing Optical Persistent Spin Helix and Stern-Gerlach Deflection in an Anisotropic Liquid Crystal Microcavity

Autoren: Mateusz Król, Katarzyna Rechcińska, Helgi Sigurdsson, Przemysław Oliwa, Rafał Mazur, Przemysław Morawiak, Wiktor Piecek, Przemysław Kula, Pavlos G. Lagoudakis, Michał Matuszewski, Witold Bardyszewski, Barbara Piętka, and Jacek Szczytko
Veröffentlicht in: Physical Review Letters, Ausgabe 127/190401, 2021, ISSN 0031-9007
Herausgeber: American Physical Society
DOI: 10.1103/physrevlett.127.190401

Universal scaling laws for charge-carrier interactions with quantum confinement in lead-halide perovskites

Autoren: Philippe Tamarat, Elise Prin, Yullia Berezovska, Anastasiia Moskalenko, Thi Phuc Tan Nguyen, Chenghui Xia, Lei Hou, Jean-Baptiste Trebbia, Marios Zacharias, Laurent Pedesseau, Claudine Katan, Maryna I. Bodnarchuk, Maksym V. Kovalenko, Jacky Even, Brahim Lounis
Veröffentlicht in: Nature Communications, 2023, Seite(n) 14, 229, ISSN 2041-1723
Herausgeber: Nature Publishing Group
DOI: 10.1038/s41467-023-35842-4

Annihilation of exceptional points from different Dirac valleys in a 2D photonic system

Autoren: M. Król, I. Septembre, P. Oliwa, M. Kędziora, K. Łempicka-Mirek, M. Muszyński, R. Mazur, P. Morawiak, W. Piecek, P. Kula, W. Bardyszewski, P. G. Lagoudakis, D. D. Solnyshkov, G. Malpuech, B. Piętka & J. Szczytko
Veröffentlicht in: Nature Communications, Ausgabe 13/5340, 2022, ISSN 2041-1723
Herausgeber: Nature Publishing Group
DOI: 10.1038/s41467-022-33001-9

Interfacial engineering to modulate surface dipoles, work functions and dielectric confinement of halide perovskites

Autoren: Pooja Basera, Boubacar Traore, Jacky Even, Claudine Katan
Veröffentlicht in: Nanoscale, 2023, ISSN 2040-3372
Herausgeber: Royal Society of chemistry
DOI: 10.1039/d3nr01126g

Controlling the nucleation and growth kinetics of lead halide perovskite quantum dots

Autoren: Quinten Akkerman, Tan Nguyen, Simon Boehme, Federico Montanarella, Dmitry Dirin, Philipp Wechsler, Finn Beiglböck, Gabriele Rainò, Rolf Erni, Claudine Katan, Jacky Even, Maksym Kovalenko
Veröffentlicht in: Science, Ausgabe 00368075, 2022, Seite(n) 1406-1412, ISSN 0036-8075
Herausgeber: American Association for the Advancement of Science
DOI: 10.1126/science.abq3616

Spontaneous Formation of Time-Periodic Vortex Cluster in Nonlinear Fluids of Light

Autoren: Kirill A. Sitnik; Sergey Alyatkin; Julian D. Töpfer; Ivan Gnusov; Tamsin Cookson; Helgi Sigurdsson; Pavlos G. Lagoudakis
Veröffentlicht in: Physical Review Letters, Ausgabe 128/237402, 2022, ISSN 0031-9007
Herausgeber: American Physical Society
DOI: 10.1103/physrevlett.128.237402

All-Optical Linear-Polarization Engineering in Single and Coupled Exciton-Polariton Condensates

Autoren: I. Gnusov, H. Sigurdsson, J.D. Töpfer, S. Baryshev, S. Alyatkin, P.G. Lagoudakis
Veröffentlicht in: Physical Review Applied, Ausgabe 16/3, 2021, ISSN 2331-7019
Herausgeber: American Physical Society
DOI: 10.1103/physrevapplied.16.034014

Bright Circularly-Polarized Photoluminescence in Chiral Layered Hybrid Lead-Halide Perovskites

Autoren: S. Liu, M. Kepenekian, S. Bodnar, S. Feldmann, M. W. Heindl, N. Fehn, J. Zerhoch, A. Shcherbakov, A. Pöthig, Y.Li, U. W. Paetzold, A. Kartouzian, I. D. Sharp, C. Katan, J. Even, F. Deschler
Veröffentlicht in: Science Advances, 2023, Seite(n) eadh5083, ISSN 2375-2548
Herausgeber: American Association for the Advancement of Science
DOI: 10.1126/sciadv.adh2255

Realizing persistent-spin-helix lasing in the regime of Rashba-Dresselhaus spin-orbit coupling in a dye-filled liquid-crystal optical microcavity

Autoren: Marcin Muszyński; Mateusz Król; Katarzyna Rechcińska; Przemysław Oliwa; Mateusz Kędziora; Karolina Łempicka-Mirek; Rafał Mazur; Przemysław Morawiak; Wiktor Piecek; Przemysław Kula; Pavlos G. Lagoudakis; Barbara Piętka; Jacek Szczytko
Veröffentlicht in: PHYSICAL REVIEW APPLIED, Ausgabe 17/014041, 2022, ISSN 2331-7019
Herausgeber: American Physical Society
DOI: 10.1103/physrevapplied.17.014041

Synthesis and Characterization of the Ternary Nitride Semiconductor Zn2VN3: Theoretical Prediction, Combinatorial Screening, and Epitaxial Stabilization

Autoren: Siarhei Zhuk, Andrey A. Kistanov, Simon C. Boehme, Noémie Ott, Fabio La Mattina, Michael Stiefel, Maksym V. Kovalenko, and Sebastian Siol
Veröffentlicht in: Chemistry of Materials, 2021, ISSN 1520-5002
Herausgeber: ACS
DOI: 10.1021/acs.chemmater.1c03025

Electrically tunable Berry curvature and strong light-matter coupling in liquid crystal microcavities with 2D perovskite

Autoren: Lempicka-Mirek, Karolina; Krol, Mateusz; Sigurdsson, Helgi; Wincukiewicz, Adam; Morawiak, Przemyslaw; Mazur, Rafal; Muszynski, Marcin; Piecek, Wiktor; Kula, Przemyslaw; Stefaniuk, Tomasz; Kaminska, Maria; De Marco, Luisa; Lagoudakis, Pavlos G.; Ballarini, Dario; Sanvitto, Daniele; Szczytko, Jacek; Pietka, Barbara
Veröffentlicht in: Science Advances, Ausgabe 8/40/eabq7533, 2022, ISSN 2375-2548
Herausgeber: American Association for the Advancement of Science
DOI: 10.1126/sciadv.abq7533

Ionic-electronic halide perovskite memdiodes enabling neuromorphic computing with a second-order complexity

Autoren: Rohit Abraham John; Alessandro Milozzi; Sergey Tsarev; Rolf Brönnimann; Simon C. Boehme; Erfu Wu; Ivan Shorubalko; Maksym V. Kovalenko; Daniele Ielmini
Veröffentlicht in: Science Advances, 8 (51), Ausgabe 18, 2022, ISSN 2375-2548
Herausgeber: Science
DOI: 10.1126/sciadv.ade0072

Reservoir optics with exciton-polariton condensates

Autoren: Y. Wang; H. Sigurdsson; J. D. Töpfer; P. G. Lagoudakis
Veröffentlicht in: Physical Review B, Ausgabe 104/235306, 2021, ISSN 2469-9950
Herausgeber: American Physical Society
DOI: 10.48550/arxiv.2109.11359

Confinement and Exciton Binding Energy Effects on Hot Carrier Cooling in Lead Halide Perovskite Nanomaterials

Autoren: Ben P. Carwithen; Thomas R. Hopper; Ziyuan Ge; Navendu Mondal; Tong Wang; Rozana Mazlumian; Xijia Zheng; Franziska Krieg; Federico Montanarella; Georgian Nedelcu; Martin Kroll; Miguel Albaladejo Siguan; Jarvist M. Frost; Karl Leo; Yana Vaynzof; Maryna I. Bodnarchuk; Maksym V. Kovalenko; Artem A. Bakulin
Veröffentlicht in: ACS Nano, Ausgabe 9, 2023, ISSN 1936-086X
Herausgeber: ACS
DOI: 10.1021/acsnano.2c12373

Screening nearest-neighbor interactions in networks of exciton-polariton condensates through spin-orbit coupling

Autoren: Denis Aristov, Helgi Sigurdsson, and Pavlos G. Lagoudakis
Veröffentlicht in: Physical Review B, Ausgabe 105/155306, 2022, ISSN 2469-9950
Herausgeber: American Physical Society
DOI: 10.1103/physrevb.105.155306

Observation of second-order meron polarization textures in optical microcavities

Autoren: Mateusz Król, Helgi Sigurdsson, Katarzyna Rechcińska, Przemysław Oliwa, Krzystof Tyszka, Witold Bardyszewski, Andrzej Opala, Michał Matuszewski, Przemysław Morawiak, Rafał Mazur, Wiktor Piecek, Przemysław Kula, Pavlos G. Lagoudakis, Barbara Piętka, Jacek Szczytko
Veröffentlicht in: Optica, Ausgabe 8/2, 2021, Seite(n) 255, ISSN 2334-2536
Herausgeber: OSA
DOI: 10.1364/optica.414891

Minor embedding with Stuart-Landau oscillator networks

Autoren: S. L. Harrison; H. Sigurdsson; P. G. Lagoudakis
Veröffentlicht in: Physical Review Research, Ausgabe 5/013018, 2023, ISSN 2643-1564
Herausgeber: American Physical Society
DOI: 10.1103/physrevresearch.5.013018

Solving the Max-3-Cut Problem with Coherent Networks

Autoren: S.L. Harrison; H. Sigurdsson; S. Alyatkin; J.D. Töpfer; P.G. Lagoudakis
Veröffentlicht in: Physical Review Applied, Ausgabe 17/024063, 2022, ISSN 2331-7019
Herausgeber: American Physical Society
DOI: 10.1103/physrevapplied.17.024063

Geometric frustration in polygons of polariton condensates creating vortices of varying topological charge

Autoren: Tamsin Cookson, Kirill Kalinin, Helgi Sigurdsson, Julian D. Töpfer, Sergey Alyatkin, Matteo Silva, Wolfgang Langbein, Natalia G. Berloff, Pavlos G. Lagoudakis
Veröffentlicht in: Nature Communications, Ausgabe 12/1, 2021, ISSN 2041-1723
Herausgeber: Nature Publishing Group
DOI: 10.1038/s41467-021-22121-3

Next nearest neighbour coupling with spinor polariton condensates

Autoren: Dovzhenko, Dmitriy; Aristov, Denis; Pickup, Lucy; Sigurdsson, Helgi; Lagoudakis, Pavlos G.
Veröffentlicht in: Physical Review B, Ausgabe 108, L161301, 2023, ISSN 2469-9950
Herausgeber: American Physical Society
DOI: 10.1103/physrevb.108.l161301

Quantum fluids of light in all-optical scatterer lattices

Autoren: S. Alyatkin, H. Sigurdsson, A. Askitopoulos, J. D. Töpfer, P. G. Lagoudakis
Veröffentlicht in: Nature Communications, Ausgabe 12/1, 2021, ISSN 2041-1723
Herausgeber: Nature Publishing Group
DOI: 10.1038/s41467-021-25845-4

Microfluidic synthesis of monodisperse and size-tunable CsPbBr<sub>3</sub> supraparticles

Autoren: Julia Nette; Federico Montanarella; Chenglian Zhu; Taras V. Sekh; Simon C. Boehme; Maryna I. Bodnarchuk; Gabriele Rainò; Philip D. Howes; Maksym V. Kovalenko; Andrew J. deMello
Veröffentlicht in: Chemical Communications, 59 (24), Ausgabe 12, 2023, Seite(n) 3554-3557, ISSN 1364-548X
Herausgeber: RSC
DOI: 10.1039/d3cc00093a

Ultra-narrow room-temperature emission from single CsPbBr3 perovskite quantum dots

Autoren: G. Rainò, N. Yazdani, S.C. Boehme, M. Kober-Czerny, C. Zhu, F. Krieg, M.D. Rossell, R. Erni, V. Wood, I. Infante and M.V. Kovalenko
Veröffentlicht in: Nature Communication, 13:2587, 1-8, Ausgabe 8, 2022, ISSN 2041-1723
Herausgeber: Nature Publishing Group
DOI: 10.1038/s41467-022-30016-0

Exact Analytical Solution for the Density Matrix of a Nonequilibrium Polariton Bose-Einstein Condensate

Autoren: Vladislav Yu. Shishkov, Evgeny S. Andrianov, Anton V. Zasedatelev, Pavlos G. Lagoudakis, and Yurii E. Lozovik
Veröffentlicht in: Physical Review Letters, Ausgabe 128/065301, 2022, ISSN 0031-9007
Herausgeber: American Physical Society
DOI: 10.1103/physrevlett.128.065301

Ultrafast Electro‐Absorption Switching in Colloidal CdSe/CdS Core/Shell Quantum Dots Driven by Intense THz Pulses

Autoren: Claudia Gollner; Rokas Jutas; Dominik Kreil; Dmitry N. Dirin; Simon C. Boehme; Andrius Baltuška; Maksym V. Kovalenko; Audrius Pugžlys
Veröffentlicht in: Advanced Optical Materials, 10 (9), Ausgabe 9, 2022, Seite(n) 2102407, ISSN 2195-1071
Herausgeber: Wiley
DOI: 10.1002/adom.202102407

Suche nach OpenAIRE-Daten ...

Leistungen

Veröffentlichungen

Diese Seite teilen

Herunterladen