We demonstrated a sensing technique for in-line ablation rate detection using a quantum cascade laser (QCL) under external optical feedback. The design of the QCL-based diagnostic system allowed to monitor the voltage modulation at the laser terminals induced by fast dynamics in the ablation process. Real-time detection of the ablation front velocity as well as in-situ investigations of the surface temperature were provided. Experimental results on fast ablation rates per pulse correlate well with the theoretical prediction. The detection range was demonstrated to be limited only by the QCL-probe emission wavelength, which is scalable up to the THz spectral region.

Date Published: 13 March 2013
PDF: 6 pages
Proc. SPIE 8607, Laser Applications in Microelectronic and Optoelectronic Manufacturing (LAMOM) XVIII, 86070O (13 March 2013); doi: 10.1117/12.2001148

Published in SPIE Proceedings Vol. 8607:
Laser Applications in Microelectronic and Optoelectronic Manufacturing (LAMOM) XVIII
Xianfan Xu; Guido Hennig; Yoshiki Nakata; Stephan W. Roth, Editor(s)