We use experimental search space mapping to examine the problem of selective nonlinear excitation with binary phase shaped femtosecond laser pulses. The search space maps represent a graphical view of all the possible solutions to the selective nonlinear excitation problem along with their experimental degrees of success. Using the information learned from these maps, we generate narrow lines w...

We calculate the cross-section for the excitation and subsequent decay of triple giant resonances (TGDR) in several nuclei excited with heavy ions. The recently developed coherent plus incoherent theory for the excitation in conjunction with the hybrid decay model of Dias-Hussein-Adhikari are used for the purpose. It is emphasized that the direct decay of the TGR is expected to deviate apprecia...

We have experimentally observed the evolution of the vacuum Rabi doublet into a singlet in the transmission spectrum of a cavity filled with a collection of two-level atoms. For very weak excitation the peaks behave like simple harmonic oscillators, but become anharmonic as the excitation increases. The anharmonicity grows to a point where hysteresis appears in the transmission spectrum, eventu...

We present the first demonstration of frequency conversion by simultaneous second- and third-harmonic generation in a silicon photonic crystal nanocavity using continuous-wave optical excitation. We observe a bright dual wavelength emission in the blue/green (450-525 nm) and red (675-790 nm) visible windows with pump powers as low as few microwatts in the telecom bands, with conversion efficien...

We study the spatial profile of high order harmonics generated by a transient grating of rotational excitation. We show that the phase modulation of the harmonic emission as a function of molecular alignment is encoded in the diffraction pattern. In molecular nitrogen, the phase difference between aligned and isotropic molecules decreases from 1.6 rad for harmonic 19 to less than 0.3 rad for ha...

Nonlinear dynamics underpin a vast array of physical phenomena ranging from interfacial motion to jamming transitions. In many cases, insight into the nonlinear behavior can be gleaned through exploration of higher order harmonics. Here, a method using band excitation scanning probe microscopy (SPM) to investigate higher order harmonics of the electromechanical response, with nanometer scale sp...

We present a compact second-harmonic-generation (SHG) microscope based on a three-port single-mode fiber coupler. The fiber coupler is used to deliver a near-infrared ultrashort-pulsed laser beam as well as to collect the SHG signal in the visible wavelength range. The SHG microscope exhibits an axial resolution of 1.8 microm, which shows a slight enhancement of the optical sectioning effect co...

In this paper, we propose an adaptive fixed code-excited linear prediction (AF-CELP) speech coder operating at 4 kbps. By exploiting the fact that a fixed codebook contribution to speech signal is also periodic as the corresponding adaptive codebook contribution, the adaptive fixed codebook model efficiently represents excitation signals. In order to overcome the quality degradation caused by t...

We present a study of the terahertz (Tilz) generation by optical rectification in a 2 mm thick <110> ZnTe crystal. The conditions for the most efficient THz generation are described. We investigate the competition between optical rectification (OR), second harmonic generation (SHG), two photon absorption (TPA) and free-carrier absorption in the diffraction limit, for excitation spot sizes small...

This paper addresses the static and dynamic stabilities of a parametrically excited torsional micro-actuator. The system is composed of a rectangular micro-mirror symmetrically suspended between two electrodes and acted upon by a steady (dc ) while simultaneously superimposed to an (ac ) voltage. First, the stability of the system subjected to a quasi-statically applied (dc ) voltage is investi...