부산대학교 도서관

We present the design of a large-area (50 mm $\, \times $ 50 mm) polyvynilidene fluoride (PVDF) pyroelectric sensor array for industrial CO$_{2}$( $\lambda =10.6\ \mu$m) laser beam positioning. The array dimensions were chosen to match the area typically monitored in the alignment procedure of external optics (beam steering moving arm system, for example) used to redirect the laser beam from the laser output window to a remote working station. The instrument is provided with a tilted, high reflection, ZnSe plate which partially transmits the laser beam onto the sensor array. From positioning simulations with a Gaussian laser intensity profile with a $\sigma = 3.2$ mm standard deviation (equivalent spot size $3\sigma \cong 20$ mm), the positional accuracy along the two orthogonal array dimensions was found to be better than 0.02 mm for an 8 $\,\times\,$8 array and one order of magnitude higher for a 16$\,\times\,$16 array. The centroid position of a CO$_{2}$ industrial laser beam was evaluated by integrating the pyroelectric current for a time comparable to the time duration (100–200 ms) of the laser pulses used in the alignment procedure.