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A marked increase in electron yield, an overall spectral red shift, and the formation of a higher energy peak from Si field emitter arrays (FEAs) are observed in photo-electron spectra throughout a laser annealing process.
A complementary dual output Mach-Zehnder modulator together with a balanced photoreceiver are used as a phase detector in an optoelectronic PLL to lock a 10.2 GHz voltage controlled oscillator to a 509 MHz mode-locked laser.
We combine steady-state propagation-rate equation and generalized nonlinear Schrödinger equation to accurately model high-repetition rate femtosecond Yb-fiber amplifiers. Such modeling reveals the nonlinear-evolution dynamics of the amplified pulse and allows the optimization of the compressed-pulse quality.
An Erbium fiber laser frequency comb operating at a GHz repetition rate is reported. The fceo and frep stabilized all-fiber system produces 2nJ sub-100fs pulses to seed octave-spanning supercontinuum generation spanning 1μm-2.4μm.
Electronic-photonic integrated circuits (EPICs) are a promising technology for overcoming bandwidth and power-consumption bottlenecks of traditional integrated circuits. Silicon is a good candidate for building such devices, due to its high-index contrast and low propagation loss at telecom wavelengths. This work presents recent advances in demonstrating discrete components built in silicon-on-insulator...
Photonic analog-to-digital converters (ADCs) are attracting significant interest due to promise of overcoming the problem of aperture jitter and improving ADC performance level by orders of magnitude. This work examines several critical factors which define the accuracy of an optically-sampled wavelength-demultiplexed ADC built on a silicon chip using silicon photonic technology. These factors are...
In few-cycle Kerr-lens mode-locked Ti:sapphire lasers, the laser crystal is exposed to extremely high intensities which can result in crystal damage and performance degradation with time. Modeling of the intracavity pulse dynamics can deepen the understanding of the different phenomena contributing to possible damage and of how to best optimize the laser performance. We present a one-dimensional laser...
The timing jitter of erbium doped, fiber optic and Titanium: Sapphire lasers, both passively mode-locked ultrafast lasers at 80 MHz, is measured with unprecedented resolution and bandwidth. Using the balanced optical cross-correlator timing detector, we found a total integrated timing jitter of 2.2 fs rms [100 Hz, 1 MHz] for the fiber supercontinuum and only 55 as rms [100 Hz, 10 MHz] jitter for the...
A fiber-based, all-optical system for femtosecond-precision, long-term, timing transfer and synchronization of microwave electronics and lasers at the kilometer scale is presented. This approach enables the implementation of femtosecond pulse, X-ray free-electron lasers, owing to the high-precision and robust operation. The system incorporates a fiber polarization controller for long-term synchronization...
Repetition rate scaling of optical parametric chirped-pulse amplification (OPCPA) systems, while highly desirable for increased photon flux, requires average pump power scaling as well to maintain pump peak intensities. Alternatively, we have proposed cavity-enhanced OPCPA (C-OPCPA) [1] to boost nonlinear drive using moderate average power sources. In C-OPCPA, pump pulses are coherently combined in...
We propose and analyze an approach to generate broadband large-spacing frequency-combs using complementary interleavers for mode-filtering and nonlinear fibers for spectral broadening. 350-nm bandwidth with negligible side-mode asymmetry is achieved.
Optical pulse trains from solid-state mode-locked lasers are expected to exhibit extremely low levels of phase noise. An optical measurement technique demonstrates an integrated phase noise of 20 as, 10 MHz to 4 kHz.
We develop an analytical approach to analyze the performance of astro-combs when amplified by a fiber amplifier. Five filtering schemes are compared to optimize side-mode suppression and radial-velocity calibration accuracy of an amplified astro-comb.
We report on a kHz, mJ-level, ultrabroadband, phase-stable 2.1-μm OPCPA for high-flux water-window high-order harmonic generation. The final stage is pumped by a high-energy, 15-ps cryogenic Yb:YAG CPA laser optically synchronized to the signal.
We demonstrate a 10GHz fs-pulse train by external repetition rate multiplication in four phase-tunable Mach-Zehnder interleavers implemented in planar waveguide technology. A minimum RF suppression ratio of −27dB can be achieved with thermal tuning.
A silicon photonics based integrated optical phase locked loop is utilized to synchronize a 10.2 GHz voltage controlled oscillator with a 509 MHz mode locked laser, achieving 32 fs integrated jitter over 300 kHz bandwidth.
We demonstrate two fully-functional channels of a real-time photonic ADC using mostly CMOS-compatible devices to optically sample and electronically digitize a 10-GHz RF signal with 37.9 dB SNR (6.0 ENOB) with a 1 GHz optical pulse train.
We report self-consistent femtosecond studies of two-photon absorption, optical Kerr-effect and free-carrier index and loss in silicon nanowaveguides using heterodyne pump-probe. Free-carrier lifetime was reduced to 33ps with only 8dB/cm added loss using proton bombardment.
A photonic ADC based on balanced detection, phase encoded optical sampling, wavelength multiplexing, and electronic quantization is demonstrated. It achieves 7.0 ENOB resolution at a 2GSa/s sub-sampling rate for a 40 GHz input analog signal.
We propose a scheme that uses a two-color pulsed radially-polarized laser beam to achieve electron acceleration exceeding 90% of the theoretical energy gain limit, over twice of what is possible with a one-color beam.
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