Relation between the Relaxation of Intrinsic Stimulated Picosecond Emission from GaAs with a Characteristic Charge-Carrier Cooling Time

Semiconductors - During the powerful picosecond optical pumping of a thin (~1 μm) GaAs layer, a stimulated intense (up to 1 GW/cm2) picosecond emission arises. It is found that the...     

Anticorrelation between the Intensity of Stimulated Picosecond Emission in GaAs and the Characteristic Time of Charge-Carrier Cooling

Semiconductors - During the powerful picosecond optical pumping, intense stimulated picosecond emission arises in a thin GaAs layer. It is found that, first, the maximum emission intensity...     

Self-synchronization of the modulation of energy-levels population with electrons in GaAs induced by picosecond pulses of probe radiation and intrinsic stimulated emission

Picosecond optical pumping leads to the initiation of intrinsic picosecond stimulated emission in GaAs. As was established previously, due to the interaction of pulses of probe radiation with those of intrinsic emission, the dependence of the absorption α of the probe pulse on its delay τ with respect to the pump pulse is modulated with oscillations. It is found that the oscillatory dependences α(τ) have a similar shape only in the case of certain combinations of energies of the interacting pulses. As a result, it is assumed that the above interaction is, in fact, a synchronization of modulations (formed by pulses) of charge-carrier populations at energy levels; this synchronization occurs in the direction of the reconstruction of detailed equilibrium. The real-time picosecond self-modulation of the absorption α is measured for the first time. The characteristics of this self-modulation as well as absorption α and intrinsic emission self-modulation characteristics measured previously by correlation methods are now accounted for by the concept of synchronization.     

Functional Dependences of the Maximum Energy Density of the Spectral Component of Stimulated Picosecond Emission by GaAs upon Gain Saturation. The Residual Characteristic Emission Relaxation Time

Semiconductors - During high-power optical picosecond pumping of the GaAs layer of an AlxGa1 – xAs–GaAs–AlxGa1 – xAs heterostructure, stimulated...     

Electron-Population Bragg Grating Induced in an AlxGa1 –xAs–GaAs–AlxGa1 –xAs Heterostructure by Intrinsic Stimulated Picosecond Emission

Semiconductors - It is shown that modulation of the spectrum of stimulated picosecond emission generated in an AlxGa1 – xAs–GaAs–AlxGa1 – xAs waveguide heterostructure upon...     

Effect of Carrier Heating by the GaAs Picosecond Stimulated Emission on Duration of Emission

Semiconductors - The real-time measured envelopes of high-power picosecond optical pumping and of the intrinsic stimulated picosecond emission of a thin GaAs layer are compared. The emission...     

Amplification Lengths of Spectral Components of Intrinsic Stimulated Picosecond Emission. Dependence of the Characteristic Relaxation Time of These Components on Their Amplification Lengths. Relation Between Stimulated and Spontaneous Emission Spectra in GaAs

Semiconductors - The high-power picosecond optical pumping of a thin GaAs layer generates intense picosecond stimulated emission. The emission spectrum is a light continuum. Based on the results of...     

Errors of measuring picosecond light pulses by picosecond streak cameras

Errors of measuring time dependences of the light intensities of picosecond laser pulses by two electron-optical systems are studied. The first system is the picosecond streak camera made in Russia, and the second system, designed in Germany, consists of a picosecond streak camera coupled with a double spec-trograph. The manufacturers test similar systems by using femtosecond pulses, however, this does not allow one to predict errors of measuring picosecond pulses. Parameters that characterize just these errors are proposed and measured. Their behavior is determined, when the amplitude (energy) of the measured pulses increases, and the influence of the cross-section shape of the light beam on the measurement accuracy is studied.     

Subterahertz self-oscillations of depletion of electron populations in the conduction band of GaAs in the presence of pumping and intrinsic stimulated radiation

It was previously found that, during picosecond optical pumping, ultrafast interrelated self-modulations of fundamental absorption of light and intrinsic stimulated picosecond radiation emerge in GaAs. In this study, quantitative evaluations confirming the assumption that the mentioned self-modulations are caused by self-oscillations of depletion of electron populations in the conduction band are made. The relation for the frequency of self-oscillations of depletion of populations is obtained. The presence of conditions for self-organization leading to the emergence of periodic nonlinear waves in nonequilibrium media, which is photogenerated electron-hole plasma with depletions of populations, is shown. As a result, in a series of studies, including this one, it is found that the collective excitation of charge carriers—self-oscillations of depletion of populations of the conduction band—emerges during pumping in GaAs under the effect of intrinsic stimulated radiation.