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Atomic Force Acoustic Microscopy (AFAM) is a type of scanning probe microscopy (SPM). It is a combination of acoustics and atomic force microscopy. The principal difference between AFAM and other forms of SPM is the addition of a transducer at the bottom of the sample which induces longitudinal out-of-plane vibrations in the specimen. These vibrations are sensed by a cantilever and tip called a probe. The figure shown here is the clear schematic of AFAM principle here B is the magnified version of the tip and sample placed on the transducer and tip having some optical coating generally gold coating to reflect the laser light on to the photodiode. Any type of material can be measured with this microscope. In particular, Nano-scale properties such as elastic modulus, shear modulus and Poisson ratio can be measured. The frequency used sweeps from some few kHz to MHz, keeping the sine wave amplitude constant. The sine longitudinal waves are sensed by the probe, and the deflection of the probe is detected by laser light focused on to a Position Sensitive Photo Diode (PSPD). This deflection of the reflected laser beam from the cantilever (probe) indicates the flexural and torsional parameters of the specimen. The high-frequency signal is sent to a lock-in amplifier and correlated with the reference signal sent by the signal generator to form the AFAM image. Since the development of Atomic Force Microscopy many modes and related techniques have emerged. Ultrasonic Force Microscopy,Ultrasonic Atomic Force Microscopy, Scanning Acoustic Force Microscopy and AFAM all come under the branch of near-field microscopy techniques called Contact Resonance Force Microscopy (CRFM). CRFM techniques depend principally on the calculation of contact resonance frequencies and how they shift with variations (like precipitates and matrix) in the sample. ==History== Atomic Force Acoustic Microscopy (AFAM) was originally developed by Ute Rabe and Walter Arnold 〔U. Rabe and W. Arnold "'' Acoustic Microscopy By Atomic-force Microscopy''" Applied Physics Letters 1994 1493-1495〕 from the Fraunhofer Institute of Nondestructive Testing in 1994. The technique has is now used for qualitative and quantitative measurements of the local elastic properties of materials. AFAM was used by Anish Kumar et al.〔A.E. Asimov and S.A. Saunin "''Atomic Force Acoustic Microscopy as a tool for polymer elastisity analysis''" (SPM 2002 Proceedings. P.79. )〕〔Anish Kumar, Ute Rabe, and Walter Arnold,"''Mapping of Elastic Stffness in an alpha + beta Titanium Alloy using Atomic Force Acoustic Microscopy"''(Japanese Journal of Applied Physics Vol. 47, No. 7, 2008, pp. 6077–6080 )〕 to map the precipitates in the polycrystalline materials. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Atomic force acoustic microscopy」の詳細全文を読む スポンサード リンク
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