Label-free optical-resolution photoacoustic microscopy of superficial microvasculature using a compact visible laser diode excitation.

Lvming Zeng,Zhongping Chen,Zhonglie Piao,Wangcun Jia,Shenghai Huang

doi:10.1364/oe.23.031026

Abstract

We have developed laser-diode-based optical-resolution photoacoustic microscopy (LD-OR-PAM) of superficial microvasculature which has the desirable properties of being compact, low-cost, and label-free. A 300-mW visible pulsed laser diode was operated at a 405 ± 5 nm wavelength with a pulse energy as low as 52 nJ. By using a 3.6 MHz ultrasound transducer, the system was tested on carbon fibers with a lateral resolution of 0.95 µm and an SNR of 38 dB. The subcutaneous microvasculature on a mouse back was imaged without an exogenous contrast agent which demonstrates the potential of the proposed prototype for skin chromophores. Our eventual goal is to offer a practical and affordable multi-wavelength functional LD-OR-PAM instrument suitable for clinical applications.

Highlights

Optical-resolution photoacoustic (PA) microscopy (OR-PAM) has made significant progress in anatomical, functional, and metabolic contrast imaging [1,2,3]
We have developed laser-diode-based optical-resolution photoacoustic microscopy (LD-optical-resolution photoacoustic (PA) microscopy (OR-PAM)) of superficial microvasculature which has the desirable properties of being compact, low-cost, and labelfree
By using a 3.6 MHz ultrasound transducer, the system was tested on carbon fibers with a lateral resolution of 0.95 μm and an signal-to-noise ratio (SNR) of 38 dB

Summary

Introduction

Optical-resolution photoacoustic (PA) microscopy (OR-PAM) has made significant progress in anatomical, functional, and metabolic contrast imaging [1,2,3] It has approached the stage where clinical instrumentation may become available in the near future. An attractive alternative is a semiconductor laser source which is relatively simple, inexpensive, compact, and robust for noninvasive PA imaging [9,10] It is widely available in the visible (VIS) to near-infrared (NIR) spectrum with a pulse repetition frequency up to a megahertz. In the past two years, the NIR pulsed laser diode has been employed with hundreds of signal averaging on an OR-PAM mode, which needs relatively low pulse optical energy to achieve a micron-scale lateral resolution [20,21,22]. The preliminary proof-of-concept prototype represents an encouraging step towards a clinical transition of OR-PAM technology

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Results

Conclusion