Profile: Karl Stetson Assocs., LLC is a provider of holographic measuring products. Our modular holography system comprises of three mod-ules: interferometer module, beam-splitter module, and illumination module. Our beam-splitter module uses a high reflection beam-splitter to direct the laser light to the object, & the remainder is reflected by two piezoelectric actuated mirrors to the fiber optic coupler. It includes two compact rotary shutters to switch the illumination & reference beams on and off independently. Our Holofringe300 interferometry program allows identification of vibration modes of a test structure as it is subjected to a vibratory excitation, and the vibration modes show up as Bessel function fringes. These fringes are dark bands on the image that read like a topographical map showing the peaks & valleys of the vibration amplitude.