When elemental sulfur (S8) is subjected to high laser power it undergoes significant burning and melting/vaporisation. In this instance a single particle on a quartz slide was hit with 90mW of 532 nm laser, focussed to a 5 µm spot. The resulting sulfur ‘splash’ is shown in the right hand optical image.
Subsequent ultra-fast Raman SWIFT™ imaging (with low laser power) allows the sulfur to be chemically imaged (left), and illustrates the presence of three components each with a distinct Raman spectrum. The distinct spectra are due to phase changes within the sulfur caused by the process of laser induced heating, melting and solidification.
The Raman image was acquired in less than 4 minutes with an acquisition time of just 5 ms per point.