Investigation of Electromagnetic Interference from a Pulsed Solid State Laser Power Supply

This paper investigates the near field, far field and conducted electromagnetic emissions in a pulsed power supply circuit for a flash lamp pumped solid-state laser amplifier. The power supply consists of a charging circuit, which energizes 300 μF of energy storage capacitor bank to 3 kV. The stored energy is discharged through a flash lamp in the form of pulsed current. It is a single shot event as commonly encountered in large scale high power laser systems. Measurements of the pulsed electromagnetic interference (EMI) are carried out in time domain with the help of a Bi-conical and a Dipole antenna for radiated noise up-to frequency range of 1 GHz, near field E-H probes and a line impedance stabilization network (LISN) for conducted line noise. The post storage time domain transient EMI signals are converted to frequency domain with the help of Welch mean square spectrum estimate in MATLAB. Quantitative measurements and characterization are helpful to understand the noise characteristics in pulsed laser power supplies, to mitigate the noise related issues and to validate them for electromagnetic compatibility (EMC) compliance standards.