Moshik Cohen

A CMOS Bidirectional 32-Element Phased-Array Transceiver at 60 GHz With LTCC Antenna

Fully integrated 32-element symmetrical TX/RX 60-GHz RF integrated circuit (RFIC) with built-in self-test is presented. The RF bidirectional power-combining architecture with shared blocks and less than 1-dB millimeter-wave transmit/receive (T/R) switch loss achieves record size and power consumption. The RFIC features an 8-dB noise figure and - 28-dBm IP1 dB in RX mode, 10-dB power gain, and Psat of +3.5 dBm per chain in TX mode. Further included are a 2-bit phase shifter, an IF converter to/from 12 GHz, and an integrated frac-N synthesizer with push-push voltage-controlled oscillator having a-93 dBc@1-MHz phase noise at 48-GHz local oscillator port. A novel high dynamic range phase and power detector is presented with 2° and ±1-dB accuracy over PVT in phase and power. A detailed analysis of both phase quantization and power distribution is presented. Array impairments such as mismatch and coupling were compared for different topologies. The RFIC is packaged on alumina for testing and on low-temperature co-fired ceramic (LTCC) for antenna integration. The 6 × 6 patch antenna on LTCC including four dummies achieves a gain of 19 dBi with scanning of ± 30°. The total root mean square amplitude and phase error of the array is 0.8 dB and 6° , respectively, resulting in a maximum array beam degradation of 1.4 dB for 2-bit quantization. The RFIC area is 29 mm2 and it consumes 1.2 W/0.85 W at TX/RX, with a 29-dBm effective isotropic radiated power at -19-dB error vector magnitude.

A CMOS bidirectional 32-element phased-array transceiver at 60GHz with LTCC antenna

Fully integrated 32-element symmetrical TX/RX 60-GHz RF integrated circuit (RFIC) with built-in self-test is presented. The RF bidirectional power-combining architecture with shared blocks and less than 1-dB millimeter-wave transmit/receive (T/R) switch loss achieves record size and power consumption. The RFIC features an 8-dB noise figure and - 28-dBm IP1 dB in RX mode, 10-dB power gain, and Psat of +3.5 dBm per chain in TX mode. Further included are a 2-bit phase shifter, an IF converter to/from 12 GHz, and an integrated frac-N synthesizer with push-push voltage-controlled oscillator having a-93 dBc@1-MHz phase noise at 48-GHz local oscillator port. A novel high dynamic range phase and power detector is presented with 2° and ±1-dB accuracy over PVT in phase and power. A detailed analysis of both phase quantization and power distribution is presented. Array impairments such as mismatch and coupling were compared for different topologies. The RFIC is packaged on alumina for testing and on low-temperature co-fired ceramic (LTCC) for antenna integration. The 6 × 6 patch antenna on LTCC including four dummies achieves a gain of 19 dBi with scanning of ± 30°. The total root mean square amplitude and phase error of the array is 0.8 dB and 6° , respectively, resulting in a maximum array beam degradation of 1.4 dB for 2-bit quantization. The RFIC area is 29 mm2 and it consumes 1.2 W/0.85 W at TX/RX, with a 29-dBm effective isotropic radiated power at -19-dB error vector magnitude.

Spatial modulation of light transmission through a single microcavity by coupling of photosynthetic complex excitations to surface plasmons.

Molecule-plasmon interactions have been shown to have a definite role in light propagation through optical microcavities due to strong coupling between molecular excitations and surface plasmons. This coupling can lead to macroscopic extended coherent states exhibiting increment in temporal and spatial coherency and a large Rabi splitting. Here, we demonstrate spatial modulation of light transmission through a single microcavity patterned on a free-standing Au film, strongly coupled to one of the most efficient energy transfer photosynthetic proteins in nature, photosystem I. Here we observe a clear correlation between the appearance of spatial modulation of light and molecular photon absorption, accompanied by a 13-fold enhancement in light transmission and the emergence of a distinct electromagnetic standing wave pattern in the cavity. This study provides the path for engineering various types of bio-photonic devices based on the vast diversity of biological molecules in nature.

Observing Optical Plasmons on a Single Nanometer Scale

The exceptional capability of plasmonic structures to confine light into deep subwavelength volumes has fashioned rapid expansion of interest from both fundamental and applicative perspectives. Surface plasmon nanophotonics enables to investigate light - matter interaction in deep nanoscale and harness electromagnetic and quantum properties of materials, thus opening pathways for tremendous potential applications. However, imaging optical plasmonic waves on a single nanometer scale is yet a substantial challenge mainly due to size and energy considerations. Here, for the first time, we use Kelvin Probe Force Microscopy (KPFM) under optical illumination to image and characterize plasmonic modes. We experimentally demonstrate unprecedented spatial resolution and measurement sensitivity both on the order of a single nanometer. By comparing experimentally obtained images with theoretical calculation results, we show that KPFM maps may provide valuable information on the phase of the optical near field. Additionally, we propose a theoretical model for the relation between surface plasmons and the material workfunction measured by KPFM. Our findings provide the path for using KPFM for high resolution measurements of optical plasmons, prompting the scientific frontier towards quantum plasmonic imaging on submolecular scales.

Enabling High Efficiency Nanoplasmonics with Novel Nanoantenna Architectures.

Surface plasmon polaritons (SPPs) are propagating excitations that arise from coupling of light with collective electron oscillations. Characterized by high field intensity and nanometric dimensions, SPPs fashion rapid expansion of interest from fundamental and applicative perspectives. However, high metallic losses at optical frequencies still make nanoplasmonics impractical when high absolute efficiency is paramount, with major challenge is efficient plasmon generation in deep nanoscale. Here we introduce the Plantenna, the first reported nanodevice with the potential of addressing these limitations utilizing novel plasmonic architecture. The Plantenna has simple 2D structure, ultracompact dimensions and is fabricated on Silicon chip for future CMOS integration. We design the Plantenna to feed channel (20 nm × 20 nm) nanoplasmonic waveguides, achieving 52% coupling efficiency with Plantenna dimensions of λ3/17,000. We theoretically and experimentally show that the Plantenna enormously outperforms dipole couplers, achieving 28 dB higher efficiency with broad polarization diversity and huge local field enhancement. Our findings confirm the Plantenna as enabling device for high efficiency plasmonic technologies such as quantum nanoplasmonics, molecular strong coupling and plasmon nanolasers.

Wireless Communication with Nanoplasmonic Data Carriers: Macroscale Propagation of Nanophotonic Plasmon Polaritons Probed by Near Field Nanoimaging

The ability to control the energy flow of light at the nanoscale is fundamental to modern communication and big-data technologies, as well as quantum information processing schemes. However, since photons are diffraction-limited, efforts of confining them to dimensions of integrated electronics have so far proven elusive. A promising way to facilitate nanoscale manipulation of light is through plasmon polaritons-coupled excitations of photons and charge carriers. These tightly confined hybrid waves can facilitate compression of optical functionalities to the nanoscale but suffer from huge propagation losses that limit their use to mostly subwavelength scale applications. With only weak evidence of macroscale plasmon polaritons, propagation has recently been reported theoretically and indirectly, no experiments so far have directly resolved long-range propagating optical plasmons in real space. Here, we launch and detect nanoscale optical signals, for record distances in a wireless link based on novel plasmonic nanotransceivers. We use a combination of scanning probe microscopies to provide high resolution real space images of the optical near fields and investigate their long-range propagation principles. We design our nanotransceivers based on a high-performance nanoantenna, Plantenna, hybridized with channel plasmon waveguides with a cross-section of 20 nm × 20 nm, and observe propagation for distances up to 1000 times greater than the plasmon wavelength. We experimentally show that our approach hugely outperforms both waveguide and wireless nanophotonic links. This successful alliance between Plantenna and plasmon waveguides paves the way for new generations of optical interconnects and expedites long-range interaction between quantum emitters and photomolecular devices.

Secondary Electron Imaging of Light at the Nanoscale

The interaction of fast electrons with metal atoms may lead to optical excitations. This exciting phenomenon forms the basis for the most powerful inspection methods in nanotechnology, such as cathodoluminescence and electron-energy loss spectroscopy. However, direct nanoimaging of light based on electrons is yet to be introduced. Here, we experimentally demonstrate simultaneous excitation and nanoimaging of optical signals using unmodified scanning electron microscope. We use high-energy electron beam for plasmon excitation and rapidly image the optical near fields using the emitted secondary electrons. We analyze dipole nanoantennas coupled with channel nanoplasmonic waveguides and observe both surface plasmons and surface plasmon polaritons with spatial resolution of 25 nm. Our experimental results are confirmed by rigorous numerical calculations based on full-wave solution of Maxwells equations, showing high correlation between optical near fields and secondary electrons images. This demonstration of optical near-field mapping using direct electron imaging provides essential insights to the exciting relations between electrons plasmons and photons, paving the way toward secondary electron-based plasmon analysis at the nanoscale.

Nanoplasmonic Metal–Insulator–Metal Waveguides

The exceptional ability of plasmonic structures to confine light into deep subwavelength volumes has fashioned rapid expansion of interest from both fundamental and applicative perspectives. Surface plasmon nanophotonics enables to investigate light–matter interaction in deep nanoscale and harness the electromagnetic and quantum properties of materials, thus opening pathways of tremendous potential applications. Predominantly, metal–insulator–metal (MIM) plasmonic waveguides are of special attentiveness as they enable to confine and manipulate light in deep nanometer scale. This work includes two sections with state-of-the-art work in the field of MIM nanoplasmonic waveguides. The first section describes novel engineerable interferometry architecture with extremely compact dimensions of λ3/15,500, which can be used to realize a variety of plasmonic logic functionalities. We use this architecture to realize the smallest reported plasmonic XOR logic gate. In the second section we use Kelvin probe force microscopy (KPFM) under optical illumination to image plasmonic waves, achieving spatial resolution of 2 nm. We fabricate a series of plasmonic MIM waveguides with gap width varied by 2 nm and experimentally resolve their propagation properties. By comparing experimentally obtained images with theoretical calculation results, we show that KPFM maps provide valuable information on the direction of optical near field. Additionally, we propose a theoretical model for the relation between surface plasmons and the material work function measured by KPFM.

Optical micro-multi-racetrack resonator filter based on SOI waveguide

In this paper, we present a new design of optical Finite Impulse Response (FIR) filter based on combination of multi-racetrack resonators realized with Silicon waveguides. Numerical investigations were carried out on the spectral response of the proposed filters design, in order to obtain FIR band-pass filter around the photonic carrier wavelength of 1.55um. The proposed FIR filter was fabricated using electron beam lithography (EBL). The device was preliminary experimentally examined by a combination of scanning electron microscopy (SEM), atomic force microscopy (AFM) and IR light coupling system. The proposed device can be useful for optical communication systems such as passive optical networks (PON).

Rapid Particle Patterning in Surface Deposited Micro-Droplets of Low Ionic Content via Low-Voltage Electrochemistry and Electrokinetics

Electrokinetic phenomena are a powerful tool used in various scientific and technological applications for the manipulation of aqueous solutions and the chemical entities within them. However, the use of DC-induced electrokinetics in miniaturized devices is highly limited. This is mainly due to unavoidable electrochemical reactions at the electrodes, which hinder successful manipulation. Here we present experimental evidence that on-chip DC manipulation of particles between closely positioned electrodes inside micro-droplets can be successfully achieved, and at low voltages. We show that such manipulation, which is considered practically impossible, can be used to rapidly concentrate and pattern particles in 2D shapes in inter-electrode locations. We show that this is made possible in low ion content dispersions, which enable low-voltage electrokinetics and an anomalous bubble-free water electrolysis. This phenomenon can serve as a powerful tool in both microflow devices and digital microfluidics for rapid pre-concentration and particle patterning.