Multipulse operation of a Ti:sapphire laser mode locked by an ion-implanted semiconductor saturable-absorber mirror (original) (raw)
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Continuous-wave versus pulse regime in a passively mode-locked laser with a fast saturable absorber
Journal of the Optical Society of America B, 2002
The phenomenon of modulation instability of continuous-wave (cw) solutions of the cubic-quintic complex Ginzburg-Landau equation is studied. It is shown that low-amplitude cw solutions are always unstable. For higher-amplitude cw solutions, there are regions of stability and regions where the cw solutions are modulationally unstable. It is found that there is an indirect relation between the stability of the soliton solutions and the modulation instability of the higher-amplitude cw solutions. However, there is no one-to-one correspondence between the two. We show that the evolution of modulationally unstable cw's depends on the system parameters.
Dispersion-managed mode-locking dynamics in a Ti:sapphire laser
Physical Review A, 2006
We present what is to our knowledge the most complete 1-D numerical analysis of the evolution and the propagation dynamics of an ultrashort laser pulse in a Ti:Sapphire laser oscillator. This study confirms the dispersion managed model of mode-locking, and emphasizes the role of the Kerr nonlinearity in generating mode-locked spectra with a smooth and well − behaved spectral phase. A very good agreement with preliminary experimental measurements is found.
Pulse evolution dynamics of a femtosecond passively mode-locked Ti:sapphire laser
Optics Letters, 1992
The pulse-formation process in a femtosecond passively mode-locked Ti:sapphire laser with a saturable absorber is investigated. The time to reach the steady state is -200 As. The formation time dependence on the dye concentration and the coincidence of the steady-state pulse width with the self-mode-locked state without a saturable absorber indicate that the function of the saturable absorber is mainly to induce the initial modulation and to shorten the pulse-formation time.
Optics Express, 2000
We report on a novel design of a cavity-dumped Ti:sapphire laser employing a semiconductor saturable absorber mirror (SESAM) to assure self-starting. With pump powers as low as 3.5 W, a stable operation is achieved, producing pulses of about 90 fs duration and single pulse energies of up to 34 nJ at 800 kHz dumping rate. The suppression ratios of the preceeding and consecutive pulses are better than 350:1, thus making this system an ideal excitation source for timecorrelated photon counting experiments.
Physical review. E, Statistical, nonlinear, and soft matter physics, 2001
The complex Ginzburg-Landau equation (CGLE) is a standard model for pulse generation in mode-locked lasers with fast saturable absorbers. We have found complicated pulsating behavior of solitons of the CGLE and regions of their existence in the five-dimensional parameter space. We have found zero-velocity, moving and exploding pulsating localized structures, period doubling (PD) of pulsations and the sequence of PD bifurcations. We have also found chaotic pulsating solitons. We have plotted regions of parameters of the CGLE where pulsating solutions exist. We also demonstrate the coexistence (bi- and multistability) of different types of pulsating solutions in certain regions of the parameter space of the CGLE.
Passive Mode-Locking of a Ti : Sapphire Laser by InGaP Quantum-Dot Saturable Absorber
IEEE Photonics Technology Letters, 2000
We demonstrate the use of a novel InGaP quantum-dot (QD) saturable absorber (SA) to induce passively mode-locked (ML) operation of a Ti : sapphire laser. Pulses as short as 518 fs are obtained at 752 nm with an average output power of up to 190 mW for 2.3 W of absorbed pump power at 532 nm. The absorption recovery of the SA is characterized by two decay coefficients: a fast and a slow component having time constants of 0.4 and 300 ps, respectively. The saturation fluence of the InGaP QDs was measured to be 28 J/cm 2 , the initial low-signal absorption was 1.5%, where 1.15% was nonsaturable loss.
Spatial–temporal analysis of the self-mode-locked Ti: sapphire laser
Journal of the Optical Society of America B, 1993
We employ our extended spatial-temporal matrices to analyze the Ti: sapphire self-mode-locked laser. Our results agree with previously reported experimental work and give us a deeper understanding of the way this laser functions. We found the pulse-shaping mechanism to be essentially solitonlike; the role of the aperture is to discriminate against cw operation. We also study the buildup of the pulse starting from a fluctuation.
Solitons in dispersion-managed mode-locked lasers
Physical Review A, 2008
The dynamics and propagation of ultrashort optical pulses generated in mode-locked lasers are investigated. The mode locking process depends crucially on the gain and loss mechanisms inside the cavity. Analytical models are introduced that include dispersion management and gain-loss terms with energy and power saturation. Comparisons of the pulse dynamics with previously well-known models are discussed. Stable soliton solutions are found for wide ranges of the parameters; the only significant requirement being sufficient gain in the system. The evolution of the system "locks" into the pure soliton solutions obtained independently with mode finding algorithms. Such solutions can be viewed as soliton wave attractors. Finally, it is shown that these solutions satisfy an asymptotic averaged system and can be approximated by elementary, Gaussian-type, functions.
Theory of mode-locked lasers containing a reverse saturable absorber
IEEE Journal of Quantum Electronics, 1985
An analytic solution is presented for mode-locking a laser using a saturable absorber and reverse saturable absorber with long relaxation times compared to the temporal pulse widths. A reverse saturable absorber is a mater'ial with an excited-state absorption cross section larger than the ground-state absorption cross section, where increasing the incident light intensity increases the absorption. The reverse saturable absorber plays an important role in mode-locking laser materials where individual pulses cannot saturate the gain. A numerical example of mode-locking a CW alexandrite laser with a reverse saturable absorber and a saturable absorber is presented.
Interaction of dual-frequency pulses in passively mode-locked lasers
We have found, numerically, that three stable pulses of diferent shapes can exist in systems described by the complex Ginzburg±Landau equation, such as passively mode-locked lasers with a fast saturable absorber. At the same cavity parameter values, however, only two of them can coexist, which two depending on the particular values of the parameters. The region of existence for each pulse is investigated numerically. The interaction between each pair of pulses is studied numerically. Using the interaction plane technique, we have found stable bound states of composite pulses.