We demonstrate a new, nonlinear optical effect of electric currents. First, a steady current is generated by applying a voltage on a doped GaAs crystal. We demonstrate that this current induces second-harmonic generation of a probe laser pulse. Second, we optically inject a transient current in an undoped GaAs crystal by using a pair of ultrafast laser pulses and demonstrate that it induces the...

Coherent phononic oscillations in Bi and Ag nanowires were studied with a femtosecond pump-probe technique. In Bi nanowires laser pulses of 50 fs excited simultaneously acoustic oscillations at a frequency of about 9.5 GHz and optical phonons in the THz range. The transmission of nanowires on a glass substrate and the light scattered from free standing nanowires were measured. In Ag nanowires l...

We present a low-complexity joint demapper-decoder scheme for coherent optical receivers with DQPSK modulation. The new technique reduces to 0.7dB the gap between QPSK and DQPSK in 100Gb/s coherent optical systems.

We demonstrate a technique for femtosecond time-resolved optical pump-probe spectroscopy that allows to scan over a nanosecond time delay at a kilohertz scan rate without mechanical delay line. Two mode-locked femtosecond lasers with approximately 1 GHz repetition rate are linked at a fixed difference frequency of fR=11 kHz. One laser delivers the pump pulses, the other provides the probe pulse...

Multidimensional Coherent optical Spectroscopy (MDCS) is an elegant and versatile tool to measure the ultrafast nonlinear optical response of materials. Of particular interest for semiconductor nanostructures, MDCS enables the separation of homogeneous and inhomogeneous linewidths, reveals the nature of coupling between resonances, and is able to identify the signatures of many-body interaction...

Optical-domain Transient Grating (TG) spectroscopy is a versatile background-free four-wave-mixing technique used to probe vibrational, magnetic and electronic degrees of freedom in the time domain. The newly developed coherent X-ray Free Electron Laser sources allow its extension regime. Xrays offer multiple advantages for TG: their large penetration depth allows probing bulk properties materi...

We present a demonstration of coherent homodyne transmission using 2-PSK at 10Gbit/s, with commercial optical components, which leads to new compact integrated receivers and new transmission formats, thus opening new possibilities for future optical systems. Introduction In most telecommunication fields outside the optical scenario, transmission systems are based on coherent detection, i.e., on...

Focusing on the transient regime, we explore atomic two-photon spectroscopy with self-aligned homodyne interferometry in a $\Lambda$-system large optical depth. The two light sources at origin of interference are single-photon transmission probe, and slow electromagnetically induced transparency. By switching off probe laser abruptly (flash effect), signal is reinforced by cooperativity, showin...

Original approval signatures are on file with the Graduate School and the University of Oregon Libraries. Electron spin coherence can arise through a coherent superposition of two spin states in the conduction band of a semiconductor and can persist over remarkably long time and length scales. The robust nature of electron spin coherence makes it an excellent model system for exploring coherent...