Preliminary Study on Infrared Holographic Imaging of Amber from the Baltic Sea

In order to explore the relationship between the optical properties and composition of amber and further establish the effective infrared parameters of amber authenticity identification, infrared holographic method was used to image and detect 5 amber samples from the Baltic Sea, and the imaging effect was analyzed by microscope and X-ray fluorescence spectroscopy. According to the principle of infrared holography, the parallel light vertical shooting optical path is built by using the near-infrared laser light source, and the hologram of different positions of the amber sample is obtained and reconstructed, and the image shows that the imaging effect of the amber sample at different locations has differences. For the difference in the infrared band transmittance of the amber sample at different locations, X-ray fluorescence spectroscopy was performed to obtain the elemental content at different locations. Combined with the infrared holographic imaging results, the analysis showed that S element and Si element were the main elements affecting the infrared transmittance of amber, and the content of S element of the testing points with inclusion was lower than that without inclucion, and the content of Si element of the testing point with inclusion was higher than that without inclusion. It was concluded that the Si element was conducive to infrared transmission, and the S element was not conducive to infrared transmission. Studies have shown that the optical path of vertical parallel light shooting is suitable for amber infrared holographic imaging, which is a new optical tool for amber characterization.