Determination of UV–visible–NIR absorption coefficient of graphite bulk using direct and indirect methods

Abstract

Absorption coefficient of graphite bulk pressed from 1-5 micrometers size crystalline grains was measured in UV-Vis-NIR range with three different methods: i) determination of pulsed laser ablation rate as the function of laser fluence for different wavelengths ˙(248nm, 337 nm, 532 nm and 1064 nm, respectively); ii) production of aerosol particles by UV laser ablation of the bulk graphite in inert atmosphere and determination of the mass-specific absorption coefficient with a four-wavelength (266 nm, 355 nm, 532 nm and 1064 nm, respectively) photoacoustic spectrometer and iii) spectroscopic ellipsometry in 250-1000 nm range. Taking into account the wide range of the absorption coefficients available in for the different carbon structures, an overall relatively good agreement was observed for the three methods. The ellipsometric results fit well with the ablation rate measurement, the data obtained with photoacoustic method are also similar in the UV and NIR region, however the values were somewhat higher in visible and near-UV range. Taking into account the limitations of the methods, they can be promising candidates for the determination of absorption coefficient when the samples are strongly scattering and there is no possibility to perform transitivity measurements.

The fabrication of optical and magnetic responsive deforming multilayered film

“…Upon the TPU film, PVA/5CB/graphite fiber film was collected by using parallel electrode electrospinning method. Graphite particles acted as a broad‐spectrum (from infrared to ultraviolet) absorbing material, which can release thermal energy to the orderly arranged 5CB for the 5CB phase transition. The shrunk 5CB can drive the blending deformation of the electrospun film and TPU film.…”

“…The principle of vis‐light responsive deformation was similar to the thermal responsive deformation, which was caused by the shrinking of stretched 5CB arranged orderly in the electrospun fibers. Graphite particles can be acted as the heating source by absorbing the energy of 405 nm vis‐light with high efficiency . Besides, Graphite particles dissolved in the PVA precursor resolution with high concentration (refer to higher light absorption) was more suitable for the usage of electrospinning.…”

Investigation on the Continuous Wave Mode and the ms Pulse Mode Fiber Laser Drilling Mechanisms of the Carbon Fiber Reinforced Composite

“…In this model, the resin matrix layer with a 0.1 mm thickness and the carbon fibers layer with a 0.06 mm thickness were separated. The model formulations [8,32,33,[38][39][40] and the calculation parameters [18,24,29] are given in the Appendix A.3 of the Appendix A.…”

“…Therefore, the numerical model only needed to use the Heat Transfer Module of COMSOL. Additionally, because the epoxy resin was transparent for the NIR laser [8,38] and the absorption depth of the 1064 nm laser inside of carbon fiber varied in the range of 74 to 270 nm [39,40], the laser energy that was absorbed at the upper surface of the carbon fibers layer was considered in this model. Thus, the boundary conditions could be written as follows: In addition, the distribution of elements in the mesh was dense at the boundary of z = 0, and the distribution gradually became sparse from the laser center of the interface to the outside in a fixed ratio.…”

Smart Devices Based on the Soft Actuator with Nafion-Polypropylene-PDMS/Graphite Multilayer Structure

“…Also, traditional carbon-based material graphite has become a popular actuator component due to its excellent optical, thermal, electrical and mechanical properties. It is able to convert light into heat effectively because it can strongly absorb a wide range of light from ultraviolet to near infrared (NIR) wavelengths [32][33][34][35].…”