Theory of Laser Energy Harvesting at Femtosecond Scale

Abstract

Energy scaling of femtosecond laser pulses has a lot of applications in nanoscale micromachining, precision time-resolution spectroscopy, high-harmonic generation, surgery, etc. Besides applied sciences and technology, there are fundamental applications of energy harvesting at femtosecond scale. In particular, it is possible to study and control intra-atom and molecular dynamics at attosecond level as well as to map the quantum processes directly with unprecedented spatial and temporal resolution. This "mesoscopic" union of classical and quantum phenomena provides with new insights into fundamental issues of quantum mechanics of open systems including possible application in the field of quantum computing. In this work, we consider a theory of femtosecond pulse energy harvesting using the dissipative soliton generation in both solid-state and fiber mode-locked lasers and the femtosecond pulse enhancement in an external resonator. The femtosecond pulse energy, width, and spectrum scaling laws are presented in the explicit and physically meaningful form.The second approach is based on the energy storing in an external high-Q resonator (so-called enhancement resonator, ER) coupled synchronously with a femtosecond pulse oscillator [26][27][28]. This simple idea faces difficulties when it is realized on a femtosecond scale because nonlinear effects and group-delay dispersion (GDD) tend to destroy a synchronization between a laser and ER. These issues will be outlined, and some modifications of ER technique will be proposed. DS energy scalingThe DS energy and width scaling are connected closely with a duality between amplification of the maximum number of laser modes and simultaneous spectral condensation, i.e., the concentration High Power Laser Systems

Stabilization of spatiotemporal dissipative solitons in multimode fiber lasers by external phase modulation

“…the τparameter is decreased). Thus, one may assume that spectral dissipation can play a decisive role in DS stabilization, similarly to the case of high-energy femtosecond solid-state and fiber lasers [63].…”

“…Nevertheless, an insight in this temporal LB splitting can be obtained by exploiting the analytical results for (1 + 1)-dimensions (i.e. when limiting the analysis to the Z − t-coordinates) [63]. In this case, it is possible construct a DS stability region, which is provided by the so-called 'master diagram', defined by the control parameter C = τ /ς in our normalization (see [63] and the references therein; the parameter ς will be defined below).…”

“…when limiting the analysis to the Z − t-coordinates) [63]. In this case, it is possible construct a DS stability region, which is provided by the so-called 'master diagram', defined by the control parameter C = τ /ς in our normalization (see [63] and the references therein; the parameter ς will be defined below). In the present case, the nonlinear mechanism providing LB formation is based on a combination of beam self-focusing with spatially graded dissipation (see equation ( 1)).…”

“…Although the ansatz (2) does not apply for the description of multiple pulse generation, using a low-dimensional model permits us to obtain the stability criterion for the DS: there is a maximal value of C, which divides the regions of either single or multiple DSs formation. This maximal C value is defined by the equation [63,66]:…”