High Precision Noncontact Photoacoustic Imaging Technique based on 3 × 3 Fiber-Optic Coupler Interferometer

Abstract

We present a high precision non-contact photoacoustic imaging technique that is implemented with an optical interferometer based on a 3×3 fiber-optic coupler. The photoacoustic signal excited by a short-pulsed laser beam is optically measured without contacting the sample surface. By utilizing the intrinsic phase difference of a 3×3 coupler-based interferometer, the quadrature signal of a conventional interferometric signal is obtained, which allows us to reconstruct the photoacoustic image precisely without suffering from the initial phase drift. The performance of the proposed scheme is confirmed by imaging various forms of absorbers embedded in polydimethylsiloxane resin blocks.