Growth and characterization of large-scale Ti:sapphire crystal using heat exchange method for ultra-fast ultra-high-power lasers

Growth of Large Ti:Sapphire Crystals by the Method of HDC with Gradient Doping

“…At the same time, the rest of the crystals have values from 0.1 to 3 MPa, which is less than the data for leucosapphire (up to 4−8 MPa). 8 Figure 6b shows the bend on the curve of distribution of stresses along the crystal length, which is connected with the nonuniformity of the thermal field and, consequently, the field of thermomechanical stresses in going from the triangular to the rectangular part of the crystal (part II Figure 2) and the formation of a defective zone in the near-bottom area.…”

“…The main disadvantages of these methods of growing bulk crystals are the nonhomogeneity of the distribution of active Ti 3+ ions and the presence of absorption centers based on Ti 4+ ions, which lead to a decrease in the generation and optical parameters of wide-aperture elements. The observed nonhomogeneity is primarily due to the segregation of the titanium impurity (the distribution coefficient of titanium ions is k Ti 3+ ≈ 0.12–0.15), the complex dynamics, and shape of the crystallization front as well as various thermodynamic conditions for cooling–annealing large crystals (in the bulk and near the surface, along the direction growth). ,− …”

Thermodynamic Calculations of Ti Ion Concentrations and Segregation Coefficients during Ti:Sapphire Crystal Growth

“…Our calculated equilibrium segregation coefficient of Ti is considerably smaller than the effective segregation coefficients reported in Table except for the result of Fielitz et al Their small value could be caused by the large rotation rate, which increases the homogeneity of solute in the melt, leading to an effective segregation coefficient close to the equilibrium segregation coefficient. From the experimental data in Table , , it is noticed that Ti:sapphire grown by the heat exchanger and the Kyropolous methods with a Mo crucible under vacuum or a reducing atmosphere usually give a high effective segregation coefficient around 0.2 and high FOM values, i.e., a high concentration ratio of Ti 3+ /Ti 4+ .…”

13.4 fs, 0.1 Hz OPCPA Front End for the 100 PW-Class Laser Facility

“…In recent years, multi-PW and 10 PW-class laser facilities have been constructed by many laboratories around the world, such as CoReLS 4.2 PW laser [2], SULF-10 PW laser [3], and ELI-10 PW laser [4]. However, limited by the available crystal size [5] and the inherent transverse parasitic lasing effect [6,7] in the Ti: sapphire crystal, it is not easy to directly boost the peak power to a higher level by using the CPA scheme.…”