Experimental study of a pulsed ytterbium-doped fibre laser with fast and slow saturable absorbers in a linear cavity

We present a linear-cavity stretched-pulse fibre laser with mode locking by a nonlinear polarization rotation and by semiconductor saturable-absorber mirrors. A Q-switched mode-locking cw train and a mode-locking pulse train are obtained in the experiment. We investigate the effects of the equivalent fast saturable absorber and the slow saturable absorbers in experiment. It is found that neither the nonlinear polarization evolution effect nor a semiconductor saturable absorber mirror is enough to produce the stable cw mode-locking pulses in this experiment. A nonlinear polarization evolution effect controls the cavity loss to literally carve the pulses; semiconductor saturable absorber mirrors provide the self-restarting and maintain the stability of the mode-locking operation.

Applications of reverse saturable absorbers in laser science

A variety of applications exist for reverse saturable absorbers (RSAs) in the area of optical pulse processing and computing. An RSA can be used as power limiter/pulse smoother and energy limiter/pulse shortner of laser pulses. A combination of RSA and saturable absorber (SA) can be used for mode locking and pulse shaping between high power laser amplifiers in oscillator amplifier chain. Also, an RSA can be used for the construction of a molecular spatial light modulator (SLM) which acts as an input/output device in optical computers. A detailed review of the theoretical studies of these processes is presented. Current efforts to find RSAs at desired wavelength for testing these theoretical predictions are also discussed.

Graphene saturable absorbers for VECSELs

We report mode-locking of an optically pumped VECSEL using a graphene-based saturable absorber mirror (GSAM). Self-starting and stable modelocked operation is demonstrated with 473 fs pulses at 1.5 GHz repetition rate and 949 nm center wavelength. Wavelength tuning is achieved over a 46 nm bandwidth. We discuss the mirror design, the fabrication of the GSAMs, and give an outlook on further optimization of the design, including dielectric top coatings to protect the graphene and to increase the flexibility in the design. © 2014 SPIE.

Passively mode-locked YVO4/Nd : YVO4 composite crystal laser with a semiconductor saturable absorber as a high reflector

A passively mode-locked diode end-pumped YVO4/Nd:YVO4 composite crystal laser with a five-mirror folded cavity was first demonstrated in this paper by using a low temperature semiconductor saturable absorber mirror grown by metal organic chemical vapor deposition. Both the Q-switching and continuous-wave mode locking operation were realized experimentally. A stable averaged output power of 10.15 W with pulse width of about 11.2-ps at a repetition rate of 113 MHz was obtained, and the optical-to-optical efficiency of 43% was achieved.

Passively mode-locked YVO4/Nd:YVO4 composite crystal green laser with a semiconductor saturable absorber mirror

A diode-pumped passively mode-locked YVO4/Nd YVO4 composite crystal green laser with a semiconductor saturable absorber mirror (SESAM) and a intracavity frequency-doubling KTP crystal was realized. The maximum average output power of 2.06 W at 532 nm with a repetition rate of 100 MHz was obtained at a pump power of 15 W, corresponding to optical slop efficiency 17.2%. The 532 nm mode-locked pulse width was estimated to be approximately 18-ps.

4-ps passively mode-locked Nd : Gd0.5Y0.5VO4 laser with a semiconductor saturable-absorber mirror

We have demonstrated a passively mode-locked diode end-pumped all-solid-state laser, which is composed of a Nd:Gd0.5Y0.5VO4 crystal and a folded cavity with a semiconductor saturable-absorber mirror grown by metal-organic chemical-vapor deposition. Stable cw mode locking with a 3.8-ps pulse duration at a repetition rate of 112 MHz was obtained. At 13.6 W of the incident pump power, a clean mode-locked fundamental-mode average output power of 3.9 W was achieved with an overall optical-to-optical efficiency of 29.0%, and the slope efficiency was 38.1%. (C) 2004 Optical Society of America.

Diode-pumped self-starting mode-locked Nd : YVO4 laser with semiconductor saturable absorber output coupler

By using a semiconductor saturable-absorber output coupler as a mode-locking device, we experimentally realized the operation of a diode-pumped passively mode-locked Nd:YVO4 laser. Stable laser pulses with duration of 2.3 ps were generated at the output power of about 1 W. With increasing the pump power to 9 W, the maximum mode-locked power of 1.7 W was obtained, which corresponds to a slope conversion efficiency of 44% and optical-to-optical conversion efficiency of 19%.

A Bragg-mirror-based semiconductor saturable absorption mirror at 800 nm with low temperature and surface state hybrid absorber

We present a novel 800-nm Bragg-mirror-based semiconductor saturable absorption mirror with low temperature and surface state hybrid absorber, with which we can realize the passive soliton mode locking of a Ti:sapphire laser pumped by 532-nm green laser which produces pulses as short as 37 fs. The reflection bandwidth of the mirror is 30 nm and the pulse frequency is 107 MHz. The average output power is 1.1 W at the pump power of 7.6 W.

Diode-end-pumped passively mode-locked ceramic Nd : YAG Laser with a semiconductor saturable mirror

We report on a diode- pumped CW passively mode locked ceramic Nd: YAG laser with SESAM ( semiconductor saturable absorber mirror), wavelength 1064nm. At a pump power of 7.6w, the pulse width was estimated to be similar to 8.3ps with repetition rate similar to 130MHz and the average output power was 1.59w. To our knowledge, this was the first demonstration that ceramic Nd: YAG was used for diode pumped CW passively mode locking. (C) 2005 Optical Society of America.

2-ps passively mode-locked Nd : YVO4 laser using an output-coupling-type semiconductor saturable absorber mirror

We have demonstrated stable self-starting passive mode-locking in a diode-end-pumped Nd: YVO4 laser using a semiconductor saturable absorber mirror (SESAM). An ln(0.25)Ga(0.75)As single quantum-well SESAM, which was grown by the metalorganic chemical-vapor deposition technique at low temperature, acts as a passive mode-locking device and an output coupler at the same time. Continuous-wave mode-locked transform-limited pulses were obtained at 1064 nm with a pulse duration of 2.1 ps and an average output power of 1.28 W at a repetition rate of 96.5 MHz. (c) 2005 American Institute of Physics.

Q-switched and mode-locked diode-pumped Nd : YVO4 laser with an intracavity composite semiconductor saturable absorber

We have demonstrated a passively Q-switched and mode-locked Nd:YVO4 laser with an intracavity composite semiconductor saturable absorber (ICSSA). Stable Q-switched and mode-locked pulses with Q-switched envelope pulse duration of 180 ns and pulse repetition rate of 72KHz have been obtained. The maximum average output power was 1.45W at 8W incident pump power. The repetition rate of the mode-locked pulses inside the Q-switched envelope was 154 MHz. Experimental results revealed that this ICSSA was suitable for Q-switched and mode-locked solid-state lasers. (c) 2007 Elsevier Ltd. All rights reserved.

A bidirectionall diode-pumped, passively mode-locked Nd : YVO4 ring laser with a low-temperature-grown semiconductor saturable absorber mirror

We report the operation of a bidirectional picosecond pulsed ring Nd:YVO4 laser based on a low-temperature-grown semiconductor saturable absorber mirror. Except for the laser crystal, the six-mirror ring laser cavity has no intra-cavity elements such as focusing lens or mirror. The bidirectional mode locked pluses are obtained at the repetition rate of 117.5 MHz, pulse duration of 81 ps, power of 2 x 200 mW.