Optoacoustic detection of nanosecond time scale photoinduced lensing effects in liquids

An all-optical photoinduced lensing method is used to excite and monitor acoustic waves in liquids. Following optical absorption, the laser pulse induces a localized temperature gradient that launches pressure waves in the excited region at the nanosecond time scale. This generates a lens-like optical element in the sample. A probe laser beam senses the refractive index change due to the acoustic and thermal effects. Piezo-optic and thermo-optic coefficients govern how the refractive index of a material changes in response to mechanical stress and temperature variations, respectively. These effects are connected to the physical properties of the liquids and can be accessed by theoretically describing the intensity signal. A complete set of physical properties of ten liquids are quantitatively described in this work. These effects find applications in a wide range of fields, from optical communication, ultrasonic imaging, and sensing to adaptive optics and fundamental research.

Automated summary

An all-optical photoinduced lensing method for exciting and monitoring acoustic waves in liquids is introduced in this article. The method utilizes a laser pulse to generate a localized temperature gradient, which launches pressure waves in the liquid at a nanosecond timescale. The refractive index change caused by acoustic and thermal effects can be sensed by a probe laser beam. The physical properties of the liquids can be quantitatively described based on the theoretical description of the intensity signal.