The two most commonly used models for passively modelocked lasers with fast saturable absorbers are the Haus modelocking equation (HME) and the cubic-quintic modelocking equation (CQME). The HME predicts an instability threshold that is unrealistically pessimistic. We use singular perturbation theory to demonstrate that the CQME has a stable high-energy solution for an arbitrarily small but non...

A saturable absorber is a nonlinear functional material widely used in laser and photonic nanodevices. Metallic nanostructures have prominent saturable absorption (SA) at the plasmon resonance frequency owing to largely enhanced ground state absorption. However, the SA of plasmonic metal nanostructures is hampered by excited-state absorption processes at very high excitation power, which usuall...

Here, we show that solution-processed Cu-Sn-S semiconductor nanocrystals (NCs) demonstrate a tunable localized surface plasmon resonance band in the near infrared region, where strong saturable absorption occurs. A saturable absorber based on these plasmonic NCs enables the construction of a stable mode-locked femtosecond fiber laser operating at the telecommunication band.

The monolithic integration of passively mode-locked solid-state lasers at highest repetition rates has been prevented by Q-switching instabilities and the lack of integrable saturable absorbers to date. In this thesis we demonstrate in theory and experiment that active feedback electronics controlling the intracavity loss of the laser is capable of suppressing the Q-switching instability. We in...

In use of saturable Cr(4+):YAG crystals, we have demonstrated the stable Q-switched and mode-locked (QML) operation of the Nd:LuVO(4) laser. The operation range of QML in use of the Cr(4+):YAG is larger than that use of SESAM and NLM. The obtained shape of Q-switched envelope, repetition rate and pulse energy are demonstrated to depend on the initial transmittance of the Cr(4+):YAG and reflecti...

It is experimentally shown that using organic materials of high nonlinear refractive index dissolved in a saturable-absorber solution permits femtosecond-pulse compression in a simple colliding-pulse mode-locked laser employing cavity-mirror dispersion adjustment.

Voltage, temperature, and intensity dependence of saturable absorption in InGaAs/InP multiple quantum wells are investigated and related to the lasing characteristics of intracavity loss modulated InGaAs/InP quantum well lasers. Bistability in the static laser light output/absorber voltage characteristic arises from the shape of the measured absorption/ voltage/intensity surface of the quantum ...

We discuss mode-locking of low-gain solid-state lasers using a semiconductor saturable Bragg reflector structure. This recently developed low-loss mode-locking device consists of a single quantum well which acts as a saturable absorber incorporated into a high-reflectivity Bragg mirror. Highly stable mode-locking in solid-state lasers results from an ultrafast transient reflectivity in the devi...

The ultrafast saturable absorption in graphene is experimentally and theoretically investigated in the femtosecond (fs) time regime. This phenomenon is well-modeled with valence band depletion, conduction band filling and ultrafast intraband carrier thermalization. The latter is dominated by intraband carrier-carrier scattering with a scattering time of 8 ( +/- 3) fs, which is far beyond the ti...