Combined VUV Absorption and Laser Absorption Spectroscopy for Atomic Oxygen Detection

Abstract

A combined vacuum ultraviolet absorption (VUV AS) and near infrared laser absorption spectroscopy (LAS) system was developed to measure atomic number density. As a VUV light source, inductively coupled plasma was used and its beam profile was determined by LAS. Firstly, this system was evaluated using cold xenon gas. As a result, the measured number density agrees with the that estimated from the partial pressure considering the absorption between the ICP and the window. Then, this system was applied to the ECR oxygen plasma. The measured number density of atomic oxygen was found to increase with the increase in the microwave power.