Four-level ultrafast modulation spectroscopy

Correlation effects of chaotic and phase-diffusion fields on polarization beats in a V-type three-level system

“…The third and fourth terms depending on the second-order coherence function, which are determined by the laser line shape, give rise to the modulation of the beat signal. This case is consistent with the result of the second-order coherence function theory [7,8], where the constant background contribution has been ignored in their analysis. Therefore, the fourth-order coherence function theory of the chaotic eld is of vital importance in PBVTS.…”

“…In the other words, we can obtain beating between the resonant frequencies of a V-type threelevel system. A Doppler-free precision can be achieved in the measurement of O 2 ¡ O 1 [7,8].…”

“…Equation (10) indicates that the modulation frequency of the beat signal equals O 2 ¡ O 1 . The overall accuracy of using PBVTS with broadband light to measure the energy-level splitting between two excited states is limited by the homogeneous linewidths [7,8].…”

“…DeBeer et al performed the rst ultrafast modulation spectroscopy (UMS) experiment in sodium vapour [6]. Fu and co-workers [7,8] then analysed the UMS with phase-conjugate geometry in a Doppler-broadened system by a second-order coherence-function theory. They found that a Doppler-free precision in the measurement of the energy-level splitting could be achieved.…”

A theoretical analysis on coherent double resonant absorptive lineshape in closely spaced transitions for λ−type five level system

“…It is already established that these phases may be field dependent and field independent. It is found that different types of four level systems under various conditions are useful for the studies of high resolution laser spectroscopy [7][8][9][10][11][12][13][14] and quantum optical phenomena [15][16][17][18][19][20]. The addition of an extra level compared to the three level one gives more controllable parameters for investigating the lineshape.…”