Measurement of the Level Relaxation Constants by the Method of Three-level Laser Spectroscopy

Vladimir A. Sychugov, G. P. Shipulo

Neli Laštovičková Streshkova

In this work, we focus on the interaction of SiV color centers in diamond with femtose- cond light pulses. In the theoretical part, a script is developed to simulate the experimen- tal varying stripe length method and the effects of saturated optical gain are investigated. In the experimental part, photoluminescence and transient differential absorption under non-resonant excitation are studied. The result of the luminescence measurements are estimates of the effective cross-sections of single-photon absorption for the wavelengths 620 nm, 515 nm and 340 nm, as well as the effective cross-section of three-photon absorp- tion for 2000 nm. The result of the differential absorption measurements is the relaxation constant of the excited level of the SiV center and the upper estimate of the time duration of the initial dynamics. 1

Aleksey I. Alekseev, Ashat M. Basharov

Neli Streshkova

In this work, we focus on the interaction of SiV color centers in diamond with femtose- cond light pulses. In the theoretical part, a script is developed to simulate the experimen- tal varying stripe length method and the effects of saturated optical gain are investigated. In the experimental part, photoluminescence and transient differential absorption under non-resonant excitation are studied. The result of the luminescence measurements are estimates of the effective cross-sections of single-photon absorption for the wavelengths 620 nm, 515 nm and 340 nm, as well as the effective cross-section of three-photon absorp- tion for 2000 nm. The result of the differential absorption measurements is the relaxation constant of the excited level of the SiV center and the upper estimate of the time duration of the initial dynamics. 1

Oleg G. Okhotnikov, José R. Salcedo

We performed spectroscopic measurements of the relaxation oscillations in a tunable Nd3+-doped fiber laser for the four-level (4F3/2-4I11/2) and for the three-level (4F3/2-4I9/2) transitions. We observed that the relaxation oscillation frequency for the three-level transition exhibited a strong wavelength dependence; in contrast, the relaxation oscillation frequency for the four-level transition did not exhibit any wavelength dependence. A simple theory to explain this remarkable feature was developed, confirming that the wavelength dependence is related to the thermal laser level population, which is significant in three-level systems but negligible in four-level systems. This should be taken into account for a careful description of laser systems, and is also instrumental for predicting oscillator or amplifier performance.

K. Talbi, J. El Qars, A. Ainane +3 more