Showing papers by "Jay E. Sharping published in 2008"
TL;DR: The first terahertz electrical measurements of single-walled carbon nanotube transistors performed in the time domain are described, showing that the high-frequency electron response is dominated by single-particle excitations rather than collective plasmon modes.
Abstract: Understanding the physics of low-dimensional systems and the operation of next-generation electronics will depend on our ability to measure the electrical properties of nanomaterials at terahertz frequencies (∼100 GHz to 10 THz). Single-walled carbon nanotubes are prototypical one-dimensional nanomaterials because of their unique band structure1,2 and long carrier mean free path3,4,5. Although nanotube transistors have been studied at microwave frequencies (100 MHz to 50 GHz)6,7,8,9,10,11, no techniques currently exist to probe their terahertz response12. Here, we describe the first terahertz electrical measurements of single-walled carbon nanotube transistors performed in the time domain. We observe a ballistic electron resonance that corresponds to the round-trip transit of an electron along the nanotube with a picosecond-scale period. The electron velocity is found to be constant and equal to the Fermi velocity, showing that the high-frequency electron response is dominated by single-particle excitations rather than collective plasmon modes. These results demonstrate a powerful new tool for directly probing picosecond electron motion in nanostructures.
136 citations
TL;DR: In this paper, the current status of fiber-based optical parametric oscillators is presented with a focus on pulsed systems employing microstructure fibers, and it is shown that systems employing short (less than a few cm) optical fibers lead to superior performance in terms of wavelength tunability and output power.
Abstract: The current status of fiber based optical parametric oscillators is presented with a focus on pulsed systems employing microstructure fibers. It is shown based on standard expressions for parametric processes in optical fibers that systems employing short (less than a few cm) optical fibers lead to superior performance in terms of wavelength tunability and output power. Practical guidelines for realizing a working system are given. These devices are now practical as ultrafast pulsed-light sources and for extending the wavelengths of operation of existing mode-locked fiber lasers.
114 citations
TL;DR: Optical spectra and autocorrelation measurements are presented that illustrate the generation of ultrashort pulses and the onset of saturation at sufficiently high pump powers.
Abstract: We report on the generation of 70-fs pulses at a center wavelength of 880 nm using a microstructure-fiber-based optical parametric oscillator pumped by a fiber laser operating at 1032 nm. We present optical spectra and autocorrelation measurements that illustrate the generation of ultrashort pulses and the onset of saturation at sufficiently high pump powers. Generation of ultrafast pulses with nanojoule energies provides new opportunities for extending the functionality of mode-locked fiber lasers.
25 citations
Patent•
26 Mar 2008TL;DR: In this article, a waveguide provides an anomalous group velocity dispersion for the optical signal and adjusts the amount of time between the higher frequency component and the lower frequency component.
Abstract: The present invention is directed towards systems and methods for adjusting intensity, wavelength and higher and lower frequency components of an optical signal. Photonic apparatus receives a first and a second optical signal. A waveguide provides an anomalous group velocity dispersion the first optical signal or the second optical signal and adjusts intensity or wavelength of the first optical signal or the second optical signal, in response to the anomalous group velocity dispersion. In some embodiments photonic apparatus receives an optical signal comprising a lower frequency component received an amount of time prior to a higher frequency component of the optical signal. A waveguide provides an anomalous group velocity dispersion for the optical signal and adjusts the amount of time between the higher frequency component and the lower frequency component in response to the anomalous group velocity dispersion.
7 citations
Posted Content•
TL;DR: In this paper, the authors demonstrate polarization-entanglement for non-degenerate and degenerate photon-pairs generated through Kerr-nonlinearity in a nano-scale silicon-on-insulator (SOI) waveguide.
Abstract: We demonstrate polarization-entanglement for non-degenerate and degenerate photon-pairs generated through Kerr-nonlinearity in a nano-scale silicon-on-insulator (SOI)waveguide. We use a compact counter propagating configuration to create two-photon polarization-entangled state, |Hi| Hi + |V i| V i . We observe two-photon interference with visibility > 91% and > 80% for nondegenerate and degenerate photon-pairs, respectively. The experimental structure can be implemented on optical chips as an integrated source of entangled photons for future quantum computer and communication applications.
6 citations
01 Jan 2008
TL;DR: In this article, the generation of correlated and entangled photons in a telecom band using Kerr nonlinearity in dispersion-shifted fiber is discussed, which allows phase matching and entanglement to be obtained over a wide range of wavelengths.
Abstract: Publisher Summary This chapter focuses on the generation of correlated and entangled photons in a telecom band using Kerr nonlinearity in dispersion-shifted fiber. Tailorable dispersion properties in microstructure fibers have allowed phase matching and entanglement to be obtained over a wide range of wavelengths. Two important features of QM are the superposition principle and the ensuing quantum entanglement. The former allows a quantum mechanical system to be in any state spanned by the basis vectors of its Hilbert space. Microstructure or holey fibers (MFs) allow phase matching to be obtained over a wide range of wavelengths because of their tailorable dispersion properties. Generation of correlated and entangled photons in MFs is demonstrated. Fiber nonlinearity as a source for correlated photons, quantum theory of four-wave mixing in optical fiber, fiber nonlinearity as a source for entangled photons, and high-fidelity entanglement with cooled fiber and degenerate photon pairs for quantum logic in the telecom band are also discussed.
2 citations
25 Nov 2008
TL;DR: In this paper, the combined effects of nonlinearity and gain-guidance on the propagation and amplification of high power parabolic pulses within fibers were explored, by choosing a suitable gain coefficient, group-velocity dispersion profile, and fiber size one can increase output power and reduce the time-bandwidth product of pulses.
Abstract: We explore the combined effects of nonlinearity and gain-guidance on the propagation and amplification of high power parabolic pulses within fibers By choosing a suitable gain coefficient, group-velocity dispersion profile, and fiber size one can increase output power and reduce the time-bandwidth product of pulses
2 citations
07 Jul 2008
TL;DR: In this article, the authors introduce slow light fundamentals and review numerous recent developments in the field, including dispersion, Kramers-Kronig relations, and hallmark experiments in atomic, fiber, solid state, and semiconductor systems.
Abstract: This tutorial will introduce slow light fundamentals and review numerous recent developments in the field. It will cover dispersion, Kramers-Kronig relations, and hallmark experiments in atomic, fiber, solid state, and semiconductor systems.
1 citations
01 Jan 2008
TL;DR: In this paper, the effects of Brillouin slow light on intensity-modulated waveforms in optical fibers were analyzed and experimental confirmation of the effects on the phase-index change of the slow light configuration was provided.
Abstract: We demonstrate a theoretical analysis and the experimental confirmation of the effects of Brillouin slow light on intensity-modulated waveforms in optical fibers. The results show that the DC and the AC parts of the waveform experience different Brillouin gain according to the modulation frequency, and the time delay of the intensity-modulated signal can be used to directly measure the phase-index change of the slow light configuration.
1 citations
04 May 2008
TL;DR: In this article, a systematic study of microstructure fibers reduced in size in order to tailor the group-velocity dispersion (GVD) is presented, which includes taper recipes, GVD measurements, SEM images, and subsequent fiber optical parametric oscillator performance.
Abstract: We present a systematic study of microstructure fibers reduced in size in order to tailor the group-velocity dispersion (GVD). The analysis includes taper recipes, GVD measurements, SEM images, and subsequent fiber optical parametric oscillator performance.
31 Jan 2008
TL;DR: In this article, the authors report on the generation of <100-fs pulses using a microstructure-fiber-based optical parametric oscillator and highlight their latest studies of oscillator stability, fiber dispersion optimization, and pump power depletion for these systems.
Abstract: We report on the generation of <100-fs pulses using a microstructure-fiber-based optical parametric oscillator. We highlight our latest studies of oscillator stability, fiber dispersion optimization, and pump power depletion for these systems.