Single-beam lifetime measurements via self-induced optical absorption

Near-field optical beam induced current measurements on heterostructures

We report near-field optical beam induced current ~NOBIC! measurements on semiconductor quantum well ~QW! structures. A subwavelength fiber tip is coupled with a tunable laser source and scanned over a sample surface. The induced photocurrent reveals the compositional profile of quantum structures. Semiconductor QW structures were designed and fabricated by molecular beam epitaxy ~MBE! to study...

Controlling of Absorption and Dispersion Spectrum via Electromagnetically Induced Transparency

In this paper we examine the absorption and dispersion properties of a weak probe field via Electromagnetically Induced Transparency (EIT) in a four-level system. It is shown that under certain condition, using this model, the absorption cancellation is appeared and the medium becomes transparent to the weak probe field. It will be shown that the controlling of absorption and dispersion spectru...

High-sensitivity, single-beam n(2) measurements.

We present a simple yet highly sensitive single-beam experimental technique for the determination of both the sign and magnitude of n(2). The sample is moved along the z direction of a focused Gaussian beam while the repetitively pulsed laser energy is held fixed. The resultant plot of transmittance through an aperture in the far field yields a dispersion-shaped curve from which n(2) is easily ...

Single-shot electron-beam bunch length measurements.

We report subpicosecond electro-optic measurements of the length of individual relativistic electron bunches. The longitudinal electron-bunch shape is encoded electro-optically on to the spectrum of a chirped laser pulse. The electron-bunch length is determined by analyzing individual laser-pulse spectra obtained with and without the presence of an electron bunch. Since the length of the chirpe...

Optical Absorption of Ion-Beam Sputtered aSi Coatings