The 10901A Polarization Axis Finder is a unique tool from TSI that provides instant indication of a laser beam's polarization axis. No twisting or turning is required, nor are measuring minimum and maximum power levels with a power meter. The actual direction of the electric vector (axis of polarization) is indicated directly by a "hourglass" or "bowtie" pattern in the beam. The 10901A also indicates polarization stability, another key parameter in system performance. Solid state pulsed laser (YAG) beam polarization can also be checked after the beam is expanded a suitable amount. Using the optimum polarization can help improve signal strength in particle imaging measurements.