A5040874355- Strong Light-Matter Interactions
- Plasmonic and Surface Plasmon Research
- Photonic and Optical Devices
- Mechanical and Optical Resonators
- Thermal Radiation and Cooling Technologies
- Terahertz technology and applications
- Nanowire Synthesis and Applications
- Silicon Nanostructures and Photoluminescence
- Semiconductor Lasers and Optical Devices
- Superconducting and THz Device Technology
- Advanced Fiber Laser Technologies
- Metamaterials and Metasurfaces Applications
- Carbon Nanotubes in Composites
- Semiconductor materials and devices
- Quantum Information and Cryptography
- Photorefractive and Nonlinear Optics
- 2D Materials and Applications
- Semiconductor Quantum Structures and Devices
- Perovskite Materials and Applications
- Spectroscopy and Laser Applications
- Machine Learning in Materials Science
- Advanced Materials and Mechanics
- Photonic Crystals and Applications
- Microfluidic and Bio-sensing Technologies
- MXene and MAX Phase Materials
École Polytechnique Fédérale de Lausanne
2023
ETH Zurich
2018-2022
University of Tehran
2013-2020
Free-space coupling to subwavelength individual optical elements is a central theme in quantum optics, as it allows the control over systems. Here we show that, by combining an asymmetric immersion lens setup and complementary resonating metasurface are able perform terahertz time-domain spectroscopy of individual, strongly meta-atom. We unravel linewidth dependence function meta-atom number indicating quenching superradiant coupling. On these grounds, investigate ultrastrongly coupled...
We probe ultra-strong light matter coupling between metallic terahertz metasurfaces and Landau-level transitions in high mobility 2D electron hole gases. utilize heavy-hole cyclotron resonances strained Ge InSb quantum wells, both within highly non-parabolic bands, compare our results to well known parabolic AlGaAs/GaAs (QW) systems. Tuning the strength of system by two methods, lithographically optical pumping, we observe a novel behavior clearly deviating from standard Hopfield model...
Photonic integrated circuits have benefited many fields in the natural sciences. Their nanoscale patterning has led to discovery of novel sources and detectors from ultraviolet microwaves. Yet terahertz technologies so far leveraged surprisingly little design material freedom provided by photonic circuits. Despite photoconduction—the process which light is absorbed above bandgap a semiconductor generate free carriers—and nonlinear up- down-conversion being two most widespread approaches...
We report a monolithic THz planar Fabry–Perot cavity fabricated with wafer bonding and provided metallic mirrors subwavelength apertures. demonstrate its coupling to the cyclotron resonance of high-mobility, two-dimensional electron gas. Q factors up 89 are observed for first mode at ≃300 GHz, cooperativity C = 56.4 normalized ratio Ωω in 17.5% third 6.4%.
We fabricate high temperature superconducting metasurfaces from yttrium–barium–copper oxide (YBCO) films via focused ion beam milling. The design of the complementary split ring resonators yields a quality factor (up to Q = 31) resonance, which is fully switchable when exploiting transition normal conducting state, achieved by heating sample above critical temperature. Meanwhile, resonance continuously visible and frequency stable under action magnetic field, up B 9 T. This makes it an ideal...
We report a novel method for the formation of hollow rod silicon nanostructures via plasma treated nanosphere lithography and reactive ion etching. The treatment polystyrene nanospheres (PS-NS) with O2 methanol–O2 gases is studied as function size, power time on substrate covered by thin layer nickel. Applying hydrogen or HCl to already polystyrenes, nano-rings nano-dots can be obtained without any physical sputtering damage. Large area nano-pillars nano-structures inner diameters 50 nm were...
Abstract Phosphorene is one of the most promising elemental 2D materials. So far, mechanical exfoliation main route toward formation phosphorene sheets. Although field‐effect transistors are realized on phosphorene, their arrangement and size dictated by randomness transfer methods. Here, evolution highly crystalline large‐area sheets with a laser‐assisted phase transition from red phosphorus directly silicon substrates in desired locations reported. The original can be patterned prior to...
Realization of luminescent porous silicon structures by a sequential reactive ion etching is reported. The process composed one and two passivation subsequences. impact substrate resistivity, plasma power the duration subsequence on porosity thickness fabricated layer are investigated, as roles shows stable photoluminescence in blue portion spectrum. Luminescence stability due to passivating oxyfluoride formed Formation controlled oxidation surface dangling bonds fluorination subsequence....
It was recently demonstrated that, in deep subwavelength gap resonators coupled to two-dimensional electron gases, propagating plasmons can lead energy leakage and prevent the formation of polaritonic resonances. This process, akin Landau damping, limits achievable field confinement thus value light-matter coupling strength. In this work, we show how plasmonic reflectors be used create an artificial stopband plasmon dispersion, confining them enabling recovery Using approach demonstrate a...
Abstract Complementary double split ring THz resonators fabricated on a 10 µm thin Si‐membrane are studied. The linewidths of the fundamental LC mode and dipolar drastically narrowing with increased resonator spacing. extracted decay rate as function density shows linear dependence, evidencing collective superradiant effect array. Furthermore, it is shown that metamaterial can be designed for low broadening resonance at high densities, is, in condition. use membrane substrate crucial, since...
The formation of high sensitivity–wide dynamic range field emission pressure sensors based on carbon nanotubes (CNTs) is reported. In this work, CNTs are grown inside an array micromachined holes in order to ensure a sensitivity and wide by allowing anode–cathode proximity while preventing direct contact simultaneously. External applied Si-based flexible anode, which results consequent variations current, due electric changes. Microcavities structure have been formed Si deep vertical etching...
Modern communication and sensing technologies rely on connecting the optical domain with microwave domain. Terahertz technologies, spanning increased frequencies from 100 GHz to 10 THz, are critical for providing larger bandwidths faster switching capabilities. Despite progress in high-frequency electronic sources detectors, these lack a direct link domain, face challenges increasing (> 1 THz). Nonlinear processes, such as rectification, offer potential solutions terahertz generation but...
We present emission up to 3 THz from a phase-matched terahertz-optical photonic circuit, featuring co-planar metallic cavity traversed by an optical rib waveguide and dipolar antenna for efficient out-coupling of terahertz waves.
We discuss recent progress in miniaturizing terahertz devices, facilitated by integrated photonic circuits. show these provide ways to engineer dispersion, achieve field enhancement and realise complex functionalities on a single chip.
Recent research revealed that in resonators with deep subwavelength gaps coupled to two-dimensional electron gases, propagating plasmons lead energy leakage, hindering polaritonic resonance. This study introduces plasmonic reflectors create an artificial stopband, confining terahertz-range and recovering resonances. Using this approach demonstrates a normalized coupling ratio of Ω R /ω 0 = . 36, enabling the observation resonances not seen without reflectors.
We present an optically packaged thin film lithium niobate device. show that this device is capable of cryogenic operation and resistant to extreme thermal shock.
Integrated photonic circuits from thin film lithium niobate are emerging as a promising platform to address the lack of miniaturized terahertz emitters and detectors within one single chip. In this talk, we will discover how transmission lines co-integrated with photonics fulfill essential requirements for efficient terahertz-optical bidirectional conversion.
We present our investigation on ultrastrong coupling of the Landau level transitions in a two dimensional electron gas to complementary split ring resonator arrays, as terahertz metasurface. To achieve higher rate, capacitive gap is reduced systematically. This increment rate expected due enhanced vacuum field fluctuations smaller volume mode. However, results indicate that size reduction introduces broadening upper polariton branch below certain width.
Abstract Silicon nanocrystals with dimensions of about 3 to 4 nm are fabricated by hydrogenation amorphous silicon layers thickness 15 nm. The strong binding the matrix, which prevents them from showing luminescence, is broken up a plasma treatment process in presence H 2 , N O, and SF 6 . Regions high nanocrystal density show more resistance against etching. By controlling etching parameters such as precursor flow rates during processes, it seems possible realize luminescent layers....