Third-order cross-correlation function of a signal of optical free induction and stochastic excitation

Баруздин Сергей Анатольевич

The third-order cross-correlations between a free induction signal of an inhomogeneously broadened two-level system and white Gaussian noise exciting this system are studied. The temporal properties of the third-order cross-correlation functions are found to correspond to the characteristics of ordinary two-and three-pulse spin and light (photon) echoes excited by determinate radio pulses. The nonlinear properties of correlation echoes are studied as functions of the noise pulse parameters. It is established that the correlation echo amplitude is determined not only by the noise pulse parameters but also by the position on the time axis of the noise counts that form the given type of echo. Finally, the behavior of the spin and light correlation echoes in the appropriate ranges is discussed.

Klaus‐Peter Dinse, M. P. Winters, J. L. Hall

By using the concept of stochastic excitation, a multichannel optical spectrometer was developed with an inherent spectral resolution in the kilohertz domain. Stochastic optical fields are obtained by phase modulating a frequency-stabilized Ar+ laser with a pseudorandom binary sequence. This sequence is characterized by an autocorrelation time of 5 nsec, with a resulting excitation bandwidth of approximately 200 MHz. A signal related to an optical free-induction decay is obtained after cross correlating the response of the system with the time-delayed stochastic excitation sequence. The performance of the spectrometer was demonstrated by observing Doppler-free transitions of molecular iodine.

В. В. Самарцев, Tatiana G. Mitrofanova

The possibility and conditions of a generation of the correlated free induction decay signals in CdSe–CdS nanostructures under two- and three-photon excitation by crossed femtosecond beams of the Ti:sapphire laser radiation are considered. It is shown that these correlated signals will be emitted in two opposite directions. The information contained in the temporal shapes and wavefronts of these signals will be correlated.

Luchun Du, Dong-Cheng Mei