Photothermal vibration spectra of square diaphragm with boss for low-pressure sensor

The low-pressure sensors (IHTM-CMTM, SP-6) with square diaphragms and concentric bosses were investigated by the photothermal elastic vibration method. The photothermal vibrations were optically excited (the focused laser beam) in different diaphragms and the generated elastic vibrations were measured with a sensitive optical probe (the double-heterodyne interferometer). The photothermal vibration frequency spectra were measured and analyzed for different types of diaphragms with a different concentric boss and each type of diaphragms on the different technological level of production. This investigation is important for analysis of the influence of the different technological processes to the vibrations of the optically driven micromechanical structures, i.e. how the technological processes change the characteristics of sensors.