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We report the synthesis of femtosecond and subfemtosecond optical field waveforms using a frequency comb consisting of the first five harmonic components of a laser. The comb components are generated in a nonlinear photonic crystal An acousto-optic modulator is used for amplitude and phase control. We synthesized the electric field into specific electric field shapes, i.e. sub-cycle cosine, sawtooth,...
Periodic femtosecond and subfemtosecond instantaneous optical field waveforms are synthesized and are verified by shaper-assisted linear cross-correlation.
We demonstrate the modified acousto-optic programmable dispersive filters can be used for the waveform synthesis consisting of five discrete harmonics spanning the blue to mid-infrared frequencies.
Attosecond optical waveforms of arbitrary shape are synthesized and verified using a Raman-generated comb of frequencies that have a controlled and stable carrier-envelope phase.
A liquid crystal spatial light modulator that operates from the ultraviolet (350 nm) to the mid-infrared (2400 nm) is described. The modulator is suitable for shaping the electromagnetic wave form of multioctave optical pulses.
Up to seven laser harmonics covering more than two octaves in frequency have been generated efficiently in a single PPLT crystal, permitting the synthesis of 1.5 femtosecond pulses in a stable and compact setting.
The feasibility of stable waveform generation by aperiodic optical superlattices is numerically demonstrated. This method allows us to deliver any desired optical waveform to a predetermined location by including phase/amplitude conpensation in the generation step.
The development of a periodic train of sub-cycle optical pulses of less than 0.5 fs electric field full-width at half-maximum and a stable and controllable carrier-envelope phase is described.
The carrier-envelope phase of Raman generated ultrashort pulses is controlled by driving the Raman coherence with a beam at near the Raman resonance frequency and its second harmonic.
Precise control of the carrier-envelope phase of Raman generated ultrashort pulses is achieved by generating a Raman frequency comb using an infrared laser pulse and its second harmonic to drive the Raman coherence.
High slope-efficiency ~25% for green-to-blue wavelength conversion, rendering 60 mW / 440 nm blue laser by 400 mW / 532 nm pump of 20 ns / 4 KHz, was demonstrated on 7.9 mum-period PPLT due to simultaneous phase matching of the 1st-order QPM-OPO with the 2nd-order QPM-SHG process.
We show that randomness in the periodicity and the duty-cycle of inverted domains in a periodically-poled crystal can result in substantial enhancement in non-phase-matched second harmonic generation. The result is corroborated by experiment.
Shaper-assisted autocorrelation is developed to characterize single-cycle pulses. The correlation signal show significantly improved signal-to-noise ratio and thus accuracy in pulse characterization when compared to cross-correlation obtained by splitting the spectral components of the pulse.
We report a new type of phase-change materials based upon the compound of In-Ga-O. It is found to exhibit two-order of magnitude resistivity change between the high-resistive amorphous phase and the low-resistive cubic phase at a phase-change temperature ~250degC. When the In-Ga-O is incorporated into a nonvolatile phase change memory (PCM) device with a double-heater (DH) structure, it exhibits an...
The fabrication of periodic poled Lithium Tantalate single crystal fibers by the laser heated pedestal growth method were achieved with in-situ monitoring of transient poling current. The whole cross section of the fiber is poled through as seen from the confocal measurement.
We report a generalized quantitative analysis of the origin of optical interference in two-dimensional nonlinear photonic crystals. The results are verified by a second harmonic generation experiment in a 2-D periodically-poled LiNbO3 crystal.
Anomalously high parametric gain and simultaneous generation of two signal beams are unique properties of an optical parametric oscillator based on a quasi-phase-matched photonic crystal with a tetragonal lattice structure.
Recent advances in engineered ferroelectric photonic structures that are robust have enabled the construction of novel devices such as monolithic RGB light sources, broadly tunable visible-UV sources, and exotic devices using 2D photonic structures.
Periodically poled lithium niobate crystal fiber (PPLNCF) has great potential to be used as tunable blue/green light source as well as wavelength converter in optical communications. Using the laser-heated pedestal growth method, PPLNCF was fabricated by an in-situ electric-field induced micro-swing poling technique. Its growth, cladding, and optical characterization will be discussed.
Novel optical devices made possible by advances in the development of ferroelectric photonic structures are described. The devices include a monolithic RGB light source, a tunable UV source, and devices created from 2D photonic structures.
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