Laser-Induced Plasma Measurements Using Nd:YAG Laser and Streak Camera: Timing Considerations

Maja S Rabasovic,Dragutin Sevic,Mihailo D Rabasovic,Bratislav P Marinkovic

doi:10.3390/atoms7010006

Abstract

We describe a streak camera system that is capable of both spatial and spectral measurements of laser-induced plasma. The system is based on a Hamamatsu C4334 streak camera and SpectraPro 2300i spectrograph. To improve the analysis of laser-induced plasma development, it is necessary to determine the timing of laser excitation in regard to the time scale on streak images. We present several methods to determine the laser signal timing on streak images—one uses the fast photodiode, and other techniques are based on the inclusion of the laser pulse directly on the streak image. A Nd:YAG laser (λ = 1064 nm, Quantel, Brilliant B) was employed as the excitation source. The problem of synchronization of the streak camera with the Q-switched Nd:YAG laser is also analyzed. A simple modification of the spectrograph enables easy switching between the spectral and spatial measurement modes.

Highlights

Laser-induced breakdown (LIB) is induced by focusing an intense laser beam on a gas, liquid, or solid target
We present several methods to to determine the laser excitation timing on streak images—one uses the fast photodiode, and the determine the laser excitation timing on streak images—one uses the fast photodiode, and the other other techniques are based on including laser pulse directly thestreak streakimage
The time-resolved laser-induced breakdown spectroscopy (LIBS) system implemented in our laboratory was based on the Nd:YAG laser, and the Optical Parametric Oscillator (OPO; Vibrant 266)

Summary

Introduction

Laser-induced breakdown (LIB) is induced by focusing an intense laser beam on a gas, liquid, or solid target. Studying the plasma formation with a high temporal, spectral, and spatial resolution is of a great interest, and the formation of laser-induced breakdown of plasma in air has been studied by many researchers [1,2,3,4,5,6], including the references presented . The requirement for easy switching between the spectral and spatial measurement modes of our streak camera system soon became apparent to us. We describe an experimental system that is capable of both spatial and spectral measurements of laser-induced plasma with picosecond temporal resolution. A similar streak camera system was used by Hori and Akamatsu [6] in a time-resolved spatial analysis of the optical emissions from laser-induced plasma in air.

Excitation System

Detection System

Determination of Synchronization Timing Using the Fast Photodiode

Spatial

Findings

Conclusions