Chapter 9 Laser Pulses Characterization with Pyroelectric Sensors

Abstract

There are many industrial and medical applications of CO2 (λ=10.6 μm) and Nd:YAG (λ=1.06 μm) infrared lasers for which the quality of the process are tightly connected to the

characteristic of the laser pulse. These two types of lasers deliver pulses with duration,

repetition frequency and power that can be controlled by means of a programmable

electronic control unit. An open-loop control generally optimize the process performances

by availing of a laser system model. However, this method cannot control that during the

operation the laser source and the optical delivering system could deteriorate; moreover

the laser beam characteristics and laser pulse temporal envelope could change by several

factors like power supply variations, optical beam misalignments, dirty deposits on mirrors,

changes in laser efficiency and many others .