Wave Pump Laser Research Articles

Depth profiles of strain in In0.10Ga0.90As/GaAs multiquantum well structures obtained by variable-pump wavelength photoluminescence

We have performed photoluminescence measurements probing the strain in a set of In0.10Ga0.90As/GaAs multiquantum well (MQW) samples. By using different continuous wave pump laser wavelengths we obtain a depth profile of strain in individual quantum wells within the MQW structure. We also present evidence for the existence of an equilibrium strain between In0.10Ga0.90As quantum well layers and GaAs barrier layers for thick strain-relaxed MQW structures.

Resonance-enhanced two-laser infrared multiple photon dissociation of gaseous ions

Abstract : Ions trapped in a Fourier Transform Ion Cyclotron Resonance (FTICR) mass spectrometer exhibited enhanced Infrared Multiple Photon Dissociation (IRMPD) when irradiated sequentially by two carbon dioxide lasers using a novel IRMPD probe/pump photodissociation scheme. A low power pulsed (probe) laser tuned to a resonant infrared absorption band promoted trapped ions to vibrationally excited states, but had insufficient energy to cause photodissociation. Subsequent irradiation of the excited ions with a fixed- frequency, nonresonant, continuous wave (pump) laser induced photofragmentation. Photodissociation spectra were obtained by varying the wavelength of the probe laser. A novel White-type cell which dramatically enhances the effect of the probe laser has been designed and constructed for use with these experiments. Infrared multiple photo dissociation, Infrared spectra of ions, Fourier transform ion cyclotron resonance mass spectrometry, Lasers, Ions, Kinetics, Gas analysis, Collisions, Molecular structure, Energy levels, Probes.

Dressed-atom approach for probe spectroscopy in Doppler-broadened three-level systems with standing-wave saturator

The three-level probe spectroscopy of Doppler-broadened transitions in the presence of a standing wave pump laser is investigated through a diagrammatic method. A probe-response diagram is defined where the resonance positions versus the probe laser frequency and absorber velocity are plotted. The dressed atom description provides a convenient method for deriving the probe response diagram and calculating the position of the Doppler-free structures on the absorption spectrum, including the ac Stark shifts. We have interpreted probe spectra on the basis of the probe response diagram, presenting new features and giving a detailed physical interpretation of all the coherent effects appearing in the spectra. Population effects are not included in the dressed system analysis and are calculated on the basis of a semiclassical treatment, but the probe response diagram provides a complete interpretation of the involved phenomena.