- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Enhanced optical Kerr nonlinearity of graphene/Si hybrid waveguide
摘要： In this work, we experimentally study the optical Kerr nonlinearities of graphene/Si hybrid waveguides with enhanced self-phase modulation. In the case of CMOS compatible materials for nonlinear optical signal processing, Si and silicon nitride waveguides have been extensively investigated over the past decade. However, Si waveguides exhibit strong two-photon absorption (TPA) at telecommunication wavelengths, which leads to a signi?cant reduction of the nonlinear ?gure-of-merit (FOM). In contrast, a silicon nitride based material system usually suppresses the TPA but simultaneously leads to the reduction of Kerr nonlinearity by one order of magnitude. Here, we introduce a graphene/Si hybrid waveguide, which maintains the optical properties and CMOS compatibility of Si waveguides, while enhancing the Kerr nonlinearity, by transferring over to the top of the waveguides. The graphene/Si waveguides are measured to have an enhanced nonlinear parameter of 510 W(cid:2)1 m(cid:2)1, compared with that of the Si waveguide of 150 W(cid:2)1 m(cid:2)1. An enhanced nonlinear FOM of 2.48 6 0.25 has been achieved, which is four times larger than that of the Si waveguide of 0.6 6 0.1. This work reveals the potential application of graphene/Si hybrid waveguides with high Kerr nonlinearity and FOM for nonlinear all-optical signal processing.
关键词： nonlinear all-optical signal processing,graphene/Si hybrid waveguide,optical Kerr nonlinearity,CMOS compatible,self-phase modulation
更新于2025-11-28 14:23:57
-
TiO <sub/>2</sub> metasurfaces: From visible planar photonics to photochemistry
摘要： TiO2 metasurfaces have been intensively studied in the past few years. To date, the TiO2 metadevices only used their high reflective index (n). The controllable light extinction coefficient (k) of TiO2 has not been exploited yet. Here, we converted TiO2 metasurfaces to black TiO2 metasurfaces and explored their new opportunities in photochemistry. A complementary metal oxide semiconductor (CMOS)–compatible technique has been developed to reversibly and precisely control the absorption of TiO2 metasurfaces without spoiling their internal nanostructures. Consequently, two types of black TiO2 metasurfaces were realized for photochemical experiments. The metasurface with an ultrawide absorption band can substantially enhance the white light absorption and accelerate the solar-based photochemistry process by a factor of 18.7. The other metasurface with an absorption band of <20 nm only responded to the resonant wavelengths, making the photochemistry process capable of being monitored in real time. In addition, the reversible switch between normal and black states makes TiO2 metasurfaces suitable for dynamic metadevices as well.
关键词： photochemistry,CMOS-compatible technique,black TiO2,dynamic metadevices,TiO2 metasurfaces
更新于2025-10-24 16:33:39
-
[IEEE 2018 IEEE International Ultrasonics Symposium (IUS) - Kobe, Japan (2018.10.22-2018.10.25)] 2018 IEEE International Ultrasonics Symposium (IUS) - High Voltage Excitation and Nonlinear Transmission of a 16 MHz AlN-Based Piezoelectric Micro-Machined Ultrasonic Transducer
摘要： This paper reports the performance of a 25 μm AlGaN-based micro-piezoelectric transducer (MPT) under high voltage excitation and determination. The proposed MPT array consists of 23×28 elements fabricated on a silicon-on-insulator (SOI) substrate with 1 μm AlGaN thin film on 24 μm silicon membrane. With all the array elements electrically connected together, the electric impedance of the MPT was 11.5–7.22 kΩ at 24.7 MHz resonance frequency in air and 3.21–7.24 kΩ at 22.8 MHz when the device was water charged. The laser Doppler vibrometer (LDV) measurements showed that the transmission efficiency and the bandwidth for free vibration were 1.6 nm/V and 1.0%, respectively. The resonance modes were specifically associated with the material parameters and the initial state of the device. Moreover, nonlinear behavior was observed when increasing the input mean power exceeded 24 mW. This strategy is potentially applied to CMOS-compatible high-resolution ultrasound imaging.
关键词： AlGaN,CMOS-compatible,Ultrasound,High voltage,Micro-piezoelectric transducer
更新于2025-09-23 15:22:29
-
Plasmonic titanium nitride via atomic layer deposition: A low-temperature route
摘要： To integrate plasmonic devices into industry, it is essential to develop scalable and CMOS compatible plasmonic materials. In this work, we report high plasmonic quality titanium nitride (TiN) on c-plane sapphire grown by plasma-enhanced atomic layer deposition. TiN with low losses, high metallicity, and a plasma frequency below 500 nm was achieved at temperatures less than 500 °C by exploring the effects of chemisorption time, substrate temperature, and plasma exposure time on the material properties. A reduction in chemisorption time mitigates premature precursor decomposition at TS > 375 °C, and a trade-off between reduced impurity concentration and structural degradation caused by plasma bombardment is achieved for 25 s plasma exposure. 85 nm thick TiN films grown at a substrate temperature of 450 °C, compatible with CMOS processes, with 0.5 s chemisorption time and 25 s plasma exposure exhibited a high plasmonic figure of merit (jε0/ε00j) of 2.8 and resistivity of 31 μΩ cm. As a result of the improved quality, subwavelength apertures were fabricated in the TiN thin films and are shown to exhibit extraordinary transmission.
关键词： plasmonic figure of merit,CMOS compatible,low-temperature route,atomic layer deposition,plasmonic titanium nitride
更新于2025-09-23 15:19:57
-
Optimal Photonic Crystal Cavities for Coupling Nanoemitters to Photonic Integrated Circuits
摘要： Photonic integrated circuits that are manufactured with mature semiconductor technology hold great promise for realizing scalable quantum technology. Efficient interfaces between quantum emitters and nanophotonic devices are crucial building blocks for such implementations on silicon chips. These interfaces can be realized as nanobeam optical cavities with high quality factors and wavelength-scale mode volumes, thus providing enhanced coupling between nano-scale quantum emitters and nanophotonic circuits. Realizing such resonant structures is particularly challenging for the visible wavelength range, where many of the currently considered quantum emitters operate, and if compatibility with modern semiconductor nanofabrication processes is desired. Here, it is shown that photonic crystal nanobeam cavities for the visible spectrum can be designed and fabricated directly on-substrate with high quality factors and small mode volumes. Designs are compared based on deterministic and mode-matching methods and the latter is found advantageous for on-substrate realizations. The results pave the way for integrating quantum emitters with nanophotonic circuits for applications in quantum technology.
关键词： CMOS compatible,photonic crystal cavities,integrated photonics,high quality factor
更新于2025-09-19 17:13:59
-
[IEEE 2019 IEEE 16th International Conference on Group IV Photonics (GFP) - Singapore, Singapore (2019.8.28-2019.8.30)] 2019 IEEE 16th International Conference on Group IV Photonics (GFP) - Germanium Photodetectors with 60-nm Absorption Coverage Extension and ～2× Quantum Efficiency Enhancement across L-Band
摘要： Germanium-on-insulator (GOI) metal-semiconductor-metal (MSM) photodetectors were demonstrated with a 60 nm extension on the absorption coverage and a ~2× enhancement on the quantum efficiency across the L-band.
关键词： germanium,longer wavelength detection,photodetectors,silicon nitride stressor,CMOS-compatible
更新于2025-09-16 10:30:52
-
[IEEE 2019 IEEE 16th International Conference on Group IV Photonics (GFP) - Singapore, Singapore (2019.8.28-2019.8.30)] 2019 IEEE 16th International Conference on Group IV Photonics (GFP) - Reliability of CMOS-Compatible Ti / n-InP and Ti / p-InGaAs Ohmic Contacts for Hybrid III-V / Si Lasers
摘要： Electrical properties of CMOS-compatible titanium contacts on n-InP and p-In0.53Ga0.47As using 300 mm tools, in the scope of integrating them on III-V / Si hybrid lasers, are presented. Electrical behaviors after i) processing, ii) integration and back-end sequences, and iii) several simulated laser uses were investigated.
关键词： III-V / Si hybrid lasers,n-InP,reliability,CMOS-compatible,titanium contacts,p-InGaAs
更新于2025-09-16 10:30:52
-
CMOS-Compatible Titanium Nitride for On-Chip Plasmonic Schottky Photodetectors
摘要： Here, we propose a waveguide-integrated plasmonic Schottky photodetector (PD) operating based on an internal photoemission process with a titanium nitride plasmonic material. The theoretically examined structure employs an asymmetric metal?semiconductor?metal waveguide configuration with one of the electrodes being gold and the second being either gold, titanium, or titanium nitride. For the first time, we measured a Schottky barrier height of 0.67 eV for titanium nitride on p-doped silicon, which is very close to the optimal value of 0.697 eV. This barrier height will enable photodetection with a high signal-to-noise ratio when operating at a wavelength of 1550 nm. In addition to the measured optical properties of high absorption losses and reasonably large real part of the permittivity that are desired for this type of PD, titanium nitride is also compatible with easy integration on existing complementary metal?oxide?semiconductor technology. The use of titanium nitride results in a shorter penetration depth of the optical mode into the metal when compared to Ti, which in turn enhances the probability for transmission of hot electrons to the adjacent semiconductor, giving rise to an enhancement in responsivity.
关键词： titanium nitride,internal photoemission,CMOS-compatible,waveguide-integrated plasmonic Schottky photodetector,signal-to-noise ratio
更新于2025-09-16 10:30:52
-
[IEEE 2019 IEEE 16th International Conference on Group IV Photonics (GFP) - Singapore, Singapore (2019.8.28-2019.8.30)] 2019 IEEE 16th International Conference on Group IV Photonics (GFP) - Germanium Photodetectors with 60-nm Absorption Coverage Extension and ～2× Quantum Efficiency Enhancement across L-Band
摘要： Germanium-on-insulator (GOI) metal-semiconductor-metal (MSM) photodetectors were demonstrated with a 60 nm extension on the absorption coverage and a ~2× enhancement on the quantum efficiency across the L-band.
关键词： silicon nitride stressor,CMOS-compatible,longer wavelength detection,photodetectors,germanium
更新于2025-09-12 10:27:22
-
Soliton-effect optical pulse compression in CMOS-compatible ultra-silicon-rich nitride waveguides
摘要： The formation of optical solitons arises from the simultaneous presence of dispersive and nonlinear properties within a propagation medium. Chip-scale devices that support optical solitons harness high field confinement and flexibility in dispersion engineering for significantly smaller footprints and lower operating powers compared to fiber-based equivalents. High-order solitons evolve periodically as they propagate and experience a temporal narrowing at the start of each soliton period. This phenomenon allows strong temporal compression of optical pulses to be achieved. In this paper, soliton-effect temporal compression of optical pulses is demonstrated on a CMOS-compatible ultra-silicon-rich nitride (USRN) waveguide. We achieve 8.7× compression of 2 ps optical pulses using a low pulse energy of ～16 pJ, representing the largest demonstrated compression on an integrated photonic waveguide to date. The strong temporal compression is confirmed by numerical calculations of the nonlinear Schr?dinger equation to be attributed to the USRN waveguide’s large nonlinearity and negligible two-photon absorption at 1550 nm.
关键词： ultra-silicon-rich nitride,nonlinear Schr?dinger equation,pulse compression,optical solitons,CMOS-compatible
更新于2025-09-11 14:15:04