An electronic device for optogalvanic technique in commercial hollow cathode discharge lamps showing the side band of diode laser

Abstract

A simple, low-noise DC power supply was built in-house has been demonstrated in this work to control a commercial hollow cathode discharge lamp. This device is able to produce output voltages of up to 400 volts at up to 50 mA current in which the current is stabilised by an active current sink. The unit also incorporated an AC coupled low-noise amplifier to detect the optogalvanic signal when excitation resonance takes place in the discharge lamp. Experiment has been performed using a single mode diode laser to investigate selected lines of argon (~772 nm) by sending the beam in the discharge lamp cathode. In the optogalvanic spectroscopic investigation of argon lines parametric studies of the tuning behaviour of our laser diode has been performed. In addition to the well known mode hops during temperature tuning also relaxation oscillation side-bands to individual modes have been detected.