Optical Trapping and Manipulation of Single Particles for Plasma Diagnostics*

Current methods for laser manipulation in dusty plasma mainly focus on manipulating a group of particles within the plasma sheath to study how dust particles interact with the plasma collectively. In our experiment, we have introduced an innovative technique called optical trapping (OT) which allows us to trap individual particles in various plasmas, including plasma jets, DC discharges, dielectric barrier discharges, and rf-powered dusty plasmas. We show that we can not only trap but also transport single particles in both dusty and weakly magnetized rf dusty plasmas in different locations. Our research demonstrates the effectiveness of the OT technology in trapping and transporting particles of different sizes and chemical properties. We utilized imaging systems to monitor the stability and movement of the trapped particles and used optical emission spectroscopy to monitor plasma plumes in real time. This new OT-plasma system demonstrates the potential of using a single trapped particle as an in-situ microscopic probe for diagnostics of dusty and magnetized dusty plasmas as well as other atmospheric plasmas.