Determination of laser beam focus position based on secondary speckles pattern analysis.

Proper positioning of a laser beam focus is a universal problem for various applications that does not have a universal solution. Quite often the taken approach relies on some sort of a calibration and temporal stability of the laser and the optical train. While such an approach can be suitable for a large number of applications its applicability becomes limited in the cases where the laser beam properties uncontrollably change with time.

Lorenz system in the thermodynamic modelling of leukaemia malignancy.

The core idea of the proposed thermodynamic modelling of malignancy in leukaemia is entropy arising within normal haematopoiesis. Mathematically its description is supposed to be similar to the Lorenz system of ordinary differential equations for simplified processes of heat flow in fluids. The hypothetical model provides a description of remission and relapse in leukaemia as two hierarchical and qualitatively different states of normal haematopoiesis with their own phase spaces.

The energy-based scaling of a thin current sheet: Case study.

The influence of average plasma energy E~ on the half thickness of a thin current sheet (TCS) is investigated for three cases of TCSs crossings. The value of was estimated from the magnetic field data by means of Cluster observations. The obtained scaling values for TCSs, Z~=ℓ/ρT, where is the thermal Larmor radius, were compared with the scaling Zμ=22E~/T, where E~ and are the average plasma energy and the temperature of plasma, which assumes a specific dynamics (conservation of magnetic flux through the trajectory segment) of the current carriers.

Exploring the depth range for three-dimensional laser machining with aberration correction.

The spherical aberration generated when focusing from air into another medium limits the depth at which ultrafast laser machining can be accurately maintained. We investigate how the depth range may be extended using aberration correction via a liquid crystal spatial light modulator (SLM), in both single point and parallel multi-point fabrication in fused silica. At a moderate numerical aperture (NA = 0.