Pure sinusoidal photo-modulation using an acousto-optic modulator

O. Tzang, D. Hershkovitz, A. Nagler, O. Cheshnovsky

Research output: Contribution to journalArticlepeer-review


We use an arbitrary waveform generator to generate a clean sinusoidal modulation from the otherwise nonlinear acousto-optic modulator (AOM). A closed loop optimization script is applied to reduce high order harmonic distortion to less than 0.05% in a high AOM diffraction efficiency regime. This low level of distortion allows us to measure the nonlinear response to photoexcitation of many materials. We demonstrate this technique in a pump-probe experiment to measure the Nonlinear Photo-Modulated Reflectivity (NPMR) of surfaces. NPMR served us as the basis for developing super-resolution microscopy for non-fluorescence samples (label-free) as well as a tool in studying the ultrafast nonlinear response of photo-excited plasmonic nano-structures. Our methodology could be applied to other imaging systems in which measuring nonlinearity is desirable, such as fluorescence and photoacoustic microscopy.

Original languageEnglish
Article number123102
JournalReview of Scientific Instruments
Issue number12
StatePublished - 1 Dec 2018


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