The custom designed 15 kHz I-shape QTF is the optimal solution to couple quartz-enhanced photoacoustic spectroscopy (QEPAS) with light source characterized by large beam diameter due to its enlarged prong spacing.

Compared to the other custom designs, the 15 kHz QTF provide a large prong spacing to accomodate large beams for multiple applications, as well as a high quality factor.

Geometrical parameters as well as resonance properties of the custom QTF are reported in the following table. Additional information about the QTF and  can be found here.