Using the QBX-08 Pockels cell driver for double-pulsed LIBS
Double-pulse Q-switched Nd:YAG laser with one resonator design using the QBX-08 special Pockels cell driver for LIBS.
Double-pulse Nd:YAG lasers are used for LIBS and PIV applications. Widely known design with two independent lasers generating two pulses (collinear or orthogonal) requires two two laser cavities, so basically all optical and electronics components are doubled; moreover lot of optics is needed to combine both beams.
The use of adjustable waveform Pockels cell driver QBX-08 lets generate two laser pulses with controllable time delay (in order of 5 us between pulses) by one laser (see pic.1). The schema is simple, and it was tested in practice for LIBS experiments, showing significant improvement of line intensities with low background. The first pulse in this scheme carries about 10-20% energy of the second pulse.
EmICCD (electronically intensified camera) which provides both high-amplification and optical gating is recommended to capture spectrum with improved S/N ratio without accumulation of back-ground from Bremsstrahlung radiation, which inevitably occurs during expansion and cooling of the dense hot plasma within first 1-2 us of plum evolution.
Two-steps voltage pulse on a Pockels cell (x10 coefficient), generated by QBX-08 on 4mm RTP Pockels cell.
The obtained double-pulsed LIBS spectrum