We demonstrate that combining the laser heating (LH) system in a diamond anvil cell (DAC) with a tandem acousto-optical tunable filter (TAOTF) allows measurement of the temperature distribution (TD) under infrared (IR, 1064 nm) LH of a specimen under high pressure in a DAC. The main component of the system is a TAOTF synchronized with a video camera. The system allows TD mapping within a temperature range of approximately 1000–2000 K on the surface of a laser-heated object (Fe plates) at high pressure in a DAC with a spatial resolution 2 µm by fitting the actual signal to Planck’s equation at each point.

We synthesized star-shaped pentagonal microcrystals of boron carbide with an extremely low carbon content (~5%), from m-carborane under high pressure (7 GPa) and high temperature (1370–1670 K). These crystals have five-fold symmetry and grow in the shape of stars. A 5-fold symmetry in large micron-sized crystals is extremely rare making this a striking observation.

We studythe effect of shear deformation on graphitic g-C₃N₄ under pressures of up to 80 GPa at room temperature. g-C₃N₄ samples are transformed from initial amorphous flakes into onion-like structures, in which the nitrogen content in the quenched samples decreases with increasing pressure (from 42% in the initial conditions to 1% at 80 GPa). The concentration of the sp² bonds also decreases from 1 (the initial sample) to 0.62 with increasing pressure to 80 GPa. This transformation of the sample is due to the fact that in the pressure range of 55–115 GPa, the equilibrium phase is not a diamond, but instead, carbon onions cross-linked by sp³ bonds, which are denser than diamonds. The results of our study show that the presence of nitrogen in sp³-bonded structures at pressures of higher than 55 GPa reduces the density and, accordingly, carbon structures without nitrogen become thermodynamically favorable.

The aim of this report is to demonstrate that the use of the laser heating (LH) system combined with an imaging tandem acousto-optical tunable filter (TAOTF) allows determination of the melting point of a solid under infrared laser (IR, 1070 nm) heating and observation of the development of melting. Statistical analysis of a selected area of speckle interference patterns on the surface of a solid specimen (tungsten plate) under laser heating was applied to detect the beginning of melting. The advantage of this method is that the LH-TAOTF system provides two dimensional (2D) temperature distribution under LH of a specimen with a spatial resolution of 2 µm. The information of the temperature distribution combined with the statistical processing of speckle enables us to determine the area and the temperature where melting begins.

Recently it has been shown that it is possible to measure the two-dimensional distribution of the surface temperature of microscopic specimens. The main component of the system is a tandem imaging acousto-optical tunable filter synchronized with a video camera. In this report, we demonstrate that combining the laser heating system with a tandem imaging acousto-optical tunable filter allows measurement of the temperature distribution under laser heating of the platinum plates as well as a visualization of the infrared laser beam, that is widely used for laser heating in diamond anvil cells.

A high-frequency scanning acoustic microscope (SAM) operating at 1–1.3 GHz was used to investigate subsurface defects in diamond-like carbon (DLC) films that were 2–3 μm thick. Because the wavelength of the longitudinal wave in the film was comparable to the film thickness, the acoustical images obtained were near-field images. To interpret the features in the acoustical images, a multidisciplinary approach was utilized through a combination of SAM with atomic force microscopy (AFM), a focused ion beam (FIB) technique, and optical microscopy. Simulations based on the rigorous theoretical approach better predict the depth of the defect than the ray optical approach. It is shown that scattering of the shear waves by subsurface defects is responsible for the acoustical contrast of the cavity.