Development of a new pulsed source for photoacoustic imaging based on aperiodically poled lithium niobate

Diego Yankelevich,J E González,Luis A Ríos,Roger S Cudney,Laura Marcu

doi:10.1364/boe.5.000468

Abstract

We present the development of a source of deep-red radiation for photoacoustic imaging. This source, which is based on two cascaded wavelength conversion processes in aperiodically poled lithium niobate, emits 10 nanosecond pulses of over 500 µJ at 710 nm. Photoacoustic images were obtained from phantoms designed to mimic the optical and acoustic properties of oral tissue. Results indicate this device is a viable source of optical pulses for photoacoustic applications.

Highlights

Photoacoustic imaging (PAI) is a three-dimensional imaging technique based on the detection of acoustic waves induced in tissue by the absorption of an optical pulse
We present the development of a source of deep-red radiation for photoacoustic imaging
This source, which is based on two cascaded wavelength conversion processes in aperiodically poled lithium niobate, emits 10 nanosecond pulses of over 500 μJ at 710 nm

Summary

Introduction

Photoacoustic imaging (PAI) is a three-dimensional imaging technique based on the detection of acoustic waves induced in tissue by the absorption of an optical pulse. For efficient photoacoustic wave generation, heat diffusion has to be negligible during the excitation pulse, which limits the pulse width to ~0.5 μs. The optical pulse sources currently used for photoacoustic imaging are, for the most part, optical parametric oscillators/amplifiers (OPO/OPA) systems pumped by frequency-doubled flashlamp-pumped Nd:YAG lasers. Since these systems have been designed for a wide range of applications, they are generally more complex and expensive than what is required for a PAI. The crystal is designed such that it down-converts radiation at 1064 nm to twice this wavelength, 2128 nm, and simultaneously produces sum-frequency generation between the incident and down-converted wavelengths, the final result being nanosecond pulses at 710 nm with sufficient energy to obtain photoacoustic signals. Using a tissue phantom designed to mimic the optical and acoustic properties of tissue, we demonstrate the ability of the source to generate images with a large signal-to-noise ratio

Design of the source of radiation at 710 nm

Concluding remarks