The paper presents some measurements of the ultra-trace of living cells and the depth of NO2 exposure of plant by using a nanosec laser-pulse-induced photoacoustic method. For the purpose of the measurement we produced a coaxial stress transducer composing a z-cut LiNbO3 single crystal. The photoacoustic measurement was performed using some samples such as human leukocyte, begonia and petunia.
