Resonance micromechanical mass sensor with holographic interferometer

We present a prototype of the mass measurement system with pico-gram resolution based on micromechanical cantilever as a sensitive element and adaptive interferometry technique with using dynamic hologram recorded in photorefractive crystal for signal decoding. Laser light pulses at wavelength 532 nm with energy 0.5 mJ and duration 7 ns are used to excite a micro-mechanical cantilever with dimensions 200×40×5 μm³. The cantilever out-of-plane mechanical vibrations were detected and their resonant frequency was measured by means of adaptive interferometer based on vectorial wave mixing in orthogonal geometry in CdTe crystal operated at cw laser light at 1.06 μm.