The goal of the project is to elucidate the mechanisms of low-frequency dynamics formation in multimode lasers and to develop approaches for its practical applications in intracavity laser spectroscopy.

The objectives of the project are:
- to develop broadband tunable cw solid-state and fibre lasers operating in the near infrared spectral range;
- to develop the comprehensive model of a solid-state laser including nonlinear mode coupling and quantum fluctuations;
- to investigate the nonlinear interaction of laser modes in different active media such as amorphous material (doped optical fibre) and crystals (Nd:YAG, Co:MgF2) and to study its influence on the spectrum of relaxation oscillations,
- to find approaches for the detection of intracavity narrow absorption lines by the form of low frequency power spectra and transfer functions;
- to study experimentally and theoretically sensitivity limits of intracavity laser spectroscopy, to optimise a laser parameters for the highest sensitivity.

It is expected that the relationship between the spectra of optical modes and relaxation oscillations in multimode Fabry-Perot lasers will open up new possibilities for using solid-state and fibre lasers in intracavity laser spectroscopy. The presence of a selective absorbing medium inside the cavity, leads to changes in the ratio of intensities of interacting modes, affecting, therefore, the low frequency dynamics of the laser. Changes in the relaxation oscillation spectrum can be very significant even at low levels of selection, caused by the intracavity absorber.