A5012794591- Superconducting and THz Device Technology
- Physics of Superconductivity and Magnetism
- Quantum and electron transport phenomena
- Photonic and Optical Devices
- Quantum Information and Cryptography
- Adaptive optics and wavefront sensing
- Quantum Computing Algorithms and Architecture
- Semiconductor Quantum Structures and Devices
- Astronomy and Astrophysical Research
- Spectroscopy and Laser Applications
- Advanced Semiconductor Detectors and Materials
- Mechanical and Optical Resonators
- Semiconductor Lasers and Optical Devices
- Thermal Radiation and Cooling Technologies
- Surface and Thin Film Phenomena
- Stellar, planetary, and galactic studies
- Optical Coatings and Gratings
- Molecular Junctions and Nanostructures
- Laser Design and Applications
- Force Microscopy Techniques and Applications
- Theoretical and Computational Physics
- Advanced MEMS and NEMS Technologies
- Analytical Chemistry and Sensors
- Astronomical Observations and Instrumentation
- Superconducting Materials and Applications
Jet Propulsion Laboratory
2013-2025
California Institute of Technology
2002-2021
University of Southern California
1987-2009
Space Micro (United States)
2002-2008
Universidade Federal de Minas Gerais
1984-1996
Southern California University for Professional Studies
1994
We demonstrate a method for fabricating arrays of plasmonic nanoparticles with separations on the order 1 nm using an angle evaporation technique. Samples fabricated thin SiN membranes are imaged high-resolution transmission electron microscopy (HRTEM) to resolve small achieved between nanoparticles. When irradiated laser light, these nearly touching metal produce extremely high electric field intensities, which result in surface-enhanced Raman spectroscopy (SERS) signals. quantify...
We directly observe low-temperature nonequilibrium quasiparticle tunneling in charge qubits based on the single-Cooper-pair box. measure even- and odd-state dwell-time distributions as a function of temperature, interpret these results using kinetic theory. While even-state lifetime is exponentially distributed, distribution more heavily weighted to short times, implying that odd-to-even tunnel events are not described by homogenous Poisson process. The mean dwell time increases sharply at...
We demonstrate the parametric amplification and noise squeezing of nanomechanical motion utilizing dispersive coupling to a Cooper-pair box qubit. By modulating qubit bias resulting mechanical resonance shift, we achieve gain 30 dB 4 dB. This qubit-mediated effect is 3000 times more effective than that from weak nonlinearity capacitance nearby electrode. technique may be used prepare squeezed states.
NASA WFIRST-AFTA mission study includes a coronagraph instrument to find and characterize exoplanets. Various types of masks could be employed suppress the host starlight about 10−9 level contrast over broad spectrum enable objectives. Such for high-contrast internal coronagraphic imaging require various fabrication technologies meet wide range specifications, including precise shapes, micron scale island features, ultralow reflectivity regions, uniformity, wave front quality, achromaticity....
We have measured the magnetoresistance of narrow (600--1000 \AA{}) and thin (150--200 gold films, one dimensional with respect to weak localization electron-electron interaction effects. It is shown that collisions small energy transfer (Nyquist phase-breaking mechanism) govern phase relaxation in such films over a wide temperature range. The Nyquist time ${\mathrm{\ensuremath{\tau}}}_{\mathit{N}}$ was estimated from data on basis theoretical dependence...
We have studied thin disordered metal films at low temperatures under nonequilibrium conditions. The electron temperature was raised above the lattice by applying a dc bias. Coulomb anomaly and weak localization were used as thermometers for electrons. confirm that below 1 K derived from either or are consistent. electron-phonon energy relaxation rate measured to be proportional ${\mathit{T}}^{3}$. Our results disagree with theoretical calculations of rates dirty metals which predict...
Continuous-wave distributed feedback interband cascade lasers operating near 3.3 μm are reported. Single longitudinal mode emission is achieved with side suppression ratio greater than 30 dB at temperatures up to 175 K. A clear Bragg stop band in the laser spectrum indicates a dominant index coupling first-order grating. Detailed characteristics of these discussed.
We have observed a few distinct anomalous avoided level crossings and voltage dependent transitions in the excited state spectrum of an Al/AlOx/Al Cooper-pair box (CPB). The device was measured at 40 mK 15 - 50 GHz frequency range. find that given crosses CPB two different gate voltages; splitting size differ depends on Josephson energy CPB. show this behavior is not only consistent with being coupled to discrete charged "two-level" quantum systems which move atomic distances junctions but...
We report measurements characterizing the performance of a kinetic inductance detector array designed for wavelength 25 microns and very low optical background level suitable applications such as far-infrared instrument on cryogenically cooled space telescope. In pulse-counting mode operation at flux, detectors can resolve individual 25-micron photons. an integrating mode, remain photon noise limited over more than 6 orders magnitude in absorbed power from 70 zW to 200 fW, with limiting...
Continuous wave (CW) operation of single-mode distributed feedback interband cascade (IC) lasers has been demonstrated at temperatures up to 261 K near ~3.3 m with side-mode-suppression ratio greater than 20 dB. The electrical power consumption is less 1.1 W over the entire operating range, which enables CW using only thermoelectric cooling from ambient temperatures.
The temperature dependence of the resistivity \ensuremath{\rho} thin gold films (thickness d=100--400 \AA{}) has been measured at T=30 mK--300 K. In a wide range below ${\mathrm{\ensuremath{\Theta}}}_{\mathit{D}}$/15 (${\mathrm{\ensuremath{\Theta}}}_{\mathit{D}}$ is Debye temperature) \ensuremath{\Delta}\ensuremath{\rho}(T)/\ensuremath{\rho} proportional to ${\mathit{T}}^{2}$ and does not depend on mean free path electrons. Experimental determinations dependences in this are good agreement...
Rigid nanoscale 2D structures of up to four individual gold nanoparticles were formed by using bifunctional organic molecules (dithiols) in combination with scanning force microscopy manipulation. These can be either precisely translated mechanical pushing across the surface or rotated about a specific axis. Experimental results are presented that show how simple geometric shapes manipulated and assembled form more complicated structures. The linked (i) forming multiparticle structure...
The Shaped Pupil Coronagraph (SPC) is a high-contrast imaging system pioneered at Princeton for detection of extra-solar earthlike planets. It designed to achieve 10<sup>-10</sup> contrast an inner working angle 4λ/D in broadband light. A critical requirement attaining this level practice the ability control wavefront phase and amplitude aberrations least λ/10<sup>4</sup> rms 1/1000 amplitude, respectively. Furthermore, has be maintained over large spectral band. High Contrast...
We present a proposed design for pair-breaking photodetector far-infrared and sub-millimeter radiation. Antenna-coupled radiation generates quasiparticles in superconducting absorber, the density of which are measured using single Cooper-pair box. Readout is performed an electromagnetic oscillator or microwave resonator, well suited frequency multiplexing large arrays. Theoretical limits to detector sensitivity discussed modeled, with predicted sensitivities rivaling transition-edge sensors...
Direct-write electron-beam lithography has proven to be a powerful technique for fabricating variety of micro and nano-optical devices. Binary E-beam is the workhorse optical devices that require complicated precision nano-scale features. We describe bi-layer resist system virtual-mark height measurement improving reliability binary patterns. Analog newer found significant application in fabrication diffractive elements. our techniques analog surface-relief profiles resist, including...
We observed a sweep rate dependence of the quantum capacitance in single Cooper-Pair box used as readout Quantum Capacitance Detector. A model was developed that fits data over five orders magnitude and optical signal power provides natural calibration absorbed power. are thereby able to measure noise equivalent detector function find it is shot-noise-limited detecting 1.5 THz photons with ranging from 1 × 10−22 W 10−17 W.
We have fabricated a single Cooper-pair box (SCB) in close proximity to electron transistor (SET) operated the radio-frequency mode (RF-SET) with an inductor and capacitor lithographed directly on chip. The RF-SET was used measure charge state of SCB revealing $2e$ periodic quantization. performed spectroscopy measurements extract charging energy ${(E}_{C})$ Josephson coupling ${(E}_{J}).$ Control temporal evolution quantum achieved by applying fast dc pulses gate. dephasing relaxation times...
A superconducting Coulomb-blockade electrometer was used to measure the Coulomb staircase of an $\mathrm{Al}∕\mathrm{Al}{\mathrm{O}}_{x}∕\mathrm{Al}$ Cooper-pair box from a temperature $30\phantom{\rule{0.3em}{0ex}}\text{to}\phantom{\rule{0.3em}{0ex}}300\phantom{\rule{0.3em}{0ex}}\mathrm{mK}$. At lowest temperature, displays effects nonequilibrium quasiparticles. As is increased, initial decrease found in width odd steps staircase, which corresponds reduction probability having quasiparticle...
The NIRCam instrument on the James Webb Space Telescope will provide coronagraphic imaging from λ =1-5 μm of high contrast sources such as extrasolar planets and circumstellar disks. A Lyot coronagraph with a variety circular wedge-shaped occulting masks matching pupil stops be implemented. occulters approximate grayscale transmission profiles using halftone binary patterns comprising wavelength-sized metal dots anti-reflection coated sapphire substrates. mask are being created in Micro...
The NIRCam instrument on the James Webb Space Telescope will have a Lyot coronagraph for high contrast imaging of extrasolar planets and circumstellar disks at λ=2 - 5 μm. Half-tone patterns are used to create graded-transmission image plane masks. These generated using electron beam lithography reactive ion etching metal layer an antireflection coated sapphire substrate. We report here manufacture evaluation flight occulters.