Pulsations In Lasers Research Articles

Self-sustained pulsations in semiconductor lasers: experimental results and theoretical confirmation

New experimental results on self-sustained pulsations in semiconductor lasers are presented and compared with theoretical predictions. These results show that laser diodes with high external differential quantum efficiency (ηext) and low coefficient of spontaneous emission coupled into lasing modes (β) have a significantly higher probability of developing pulsations, which is in good agreement with theoretical predictions. Furthermore, these results provide strong evidence that the laser cavity contains defects which act as optically saturable absorbing centers. These may be incorporated into the active layer of the laser during crystal growth and/or subsequent fabrication.

Pulsating ion laser action observed in a magnetically confined plasma

Pulsating laser emission from the strong blue-green lines of Ar II at a self-repetition frequency up to 15 kHz has been observed in a magnetically confined argon plasma during a quasisteady low-pressure discharge. The laser output power and pulsation frequency are found to vary sensitively with the magnetic field strength, gas pressure, and discharge current. The phenomenon is interpreted as being caused by self-excited radial oscillations of the confined plasma which drives the population inversion density of the Ar+ ions within the prealigned optical cavity to rise and fall periodically above and below the lasing threshold.

Structural mechanism of laser spiking

A mechanism of laser pulsations is proposed. The time-space phase modulation arises due to Bragg scattering of counterrunning waves from the self-induced population inversion periodic structure in the active medium.

7B11 - Theory of pulsating conditions for lasers

A general equation is derived for the dynamical behavior of the laser. The analytic form of the family of solutions to this equation is found for the practically most important case of deep modulation of the laser output. The obtained results are used for studying a series of the following actual problems: external regulation of laser pulsation, establishment of continuous pulsating conditions for the maser and semiconductor lasers, and a study of periodic pulsations in a laser with a saturating filter.