  In this paper, the photoacoustic spectroscopy technique based on lithium
niobate crystals is initially reported, to our knowledge. A novel
dual-cantilever tuning fork structure and new electrodes have been designed
using Y-cut 128{\deg} blackened lithium niobate wafers. The tuning fork, with a
resonant frequency of only 10.46 kHz and a prong gap of 1 mm, is engineered to
achieve superior performance in photoacoustic spectroscopy. In the
demonstration experiment, acetylene was detected using a 1.53 um semiconductor
laser, achieving a detection limit of about 9 ppb within a one-second
integration time.
