چكيده به لاتين
In this research, for the first time in the country, a hybrid single longitudinal mode laser has been carried out that has expansive and fundamental applications in laser spectroscopy researches and optical pumping processes. In this regard, an optical array including a low pressure continuous wave (CW) and a 3 atm pulsed CO2 laser have been used. In this optical arrangement, the discharge tubes of the continuous wave and pulsed CO2 lasers were located inside a single optical resonator. So that, owing to the additional amplification in the CW medium for only one longitudinal mode, a single mode oscillation in the whole of the configuration has been established, resulting in single longitudinal mode laser pulses. The temporal shape of these single mode pulses, detected by photon drag and displayed on oscilloscope, has a smooth profile without any spikes or roughness due to the mode beating effect. Single mode performance of this laser has a threshold pressure for the CW laser at 7 mbar.
Furthermore, the behavior of these single mode pulses at different pressures and powers of the CW laser for above and below threshold conditions has been studied. It has been shown that in both above and below threshold conditions the duration, rise time and drop time of the single mode pulses are higher than the related values in multimode regime. While, the single mode pulses build time is lower than that of the multimode pulses. In addition, maximum points have been found for the duration, rise time and drop time of the single mode pulses that occur at 9.5 mbar oscillation threshold pressure of the CW laser.
On the whole, the hybrid configuration has many advantages over other methods. Perhaps the most valuable and most prominent of these advantages is the independence from the compatibility and tuning of two separate resonators. Because this configuration has a single resonator, and the low-pressure and high-pressure sections will inevitably fluctuate on a mode that is compatible with the same resonator.
Keywords: CO2 lasers, single mode lasers, hybrid configuration
