The process of four photon parametric mixing can be used to convert the input laser sources, working in CW and pulse regimes, into light at several different frequencies. An effective parametric energy conversion can be observed when phase matching conditions between the waves are satisfied. The basic theoretical investigations are focused on efficiency of the four-photon mixing and parametric gain with applications such as all-optical signal sampling, time-demultiplexing, pulse generation and wavelength conversion. The parametric amplifiers have capacity to provide high gain and low noise at arbitrary wavelengths with proper fiber design and pump wavelength allocation. The problem with the generation of new frequencies on distances less than one coherent length in the process of parametric four-photon mixing was solved in approximation of fixed electric field of the pump wave. The idea of our research is to solve the more general problem in which it is taken into account the mutual action of the first and second order of dispersion and all real χ(3) nonlinear processes on the parametric four-photon mixing. In CW regime the solutions of the problem, presented above, was solved in the form of Jacobi elliptic functions. In pulse regime we found optimal conditions, where the process of energy exchange is still effective. In this regime a quasi-periodic conversion is observed and group velocity difference between the pump and signal wave is compensated by nonlinear mechanisms.
In recent experiments in air with femtosecond pulses significant depolarization effects in nonlinear regime were observed. We use the generalized cubic type nonlinearity and investigate how this operator influences the vector field polarization. A vector set of nonlinear differential equations describing the evolution of the main and signal is derived. The polarization properties of the components of vector fields are investigated numerically.
We present experimental and theoretical investigation of the first picoseconds of formation of white continuum from 100 fs laser pulse in 0.5 cm BK7 glass. The theory gives an answer to the question of the physical mechanism of asymmetrical ultra-broadening of the pulses in the initial moment of filamentation. The spectra obtained from the experiment are compared with the spectrum profiles of the physical model and are in very good coincidence.
We investigate the propagation in air of laser pulses in linear and nonlinear regime. The mathematical model presented in the paper describes the propagation of pulses with narrow-band spectrum, as well as the evolution of broad-band ones. It is shown that the diffraction of pulses with super-broad spectrum or pulses with a few cycles under the envelope is closer to wave type. For such pulses, a new physical mechanism of balance between non-paraxial diffraction and third order nonlinearity appears. We investigate in more detail the nonlinear third order polarization, taking into account the carrier to envelope phase. This additional phase transforms the third harmonic term to GHz terms, which start to generate radiation when the pulse duration reaches the femtosecond range.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.