Photo-acoustic microscopic imaging system and method based on surface plasmon resonance

Abstract

The invention discloses a photo-acoustic microscopic imaging system and method based on surface plasmon resonance. The system generates exciting light, the exciting light acts on photo-acoustic wavesacting on a liquid interface and generated and returned by a measured object, a refraction index of the liquid interface is changed along with variation of the pressure of the photo-acoustic waves, the system further generates probe light, a probe light path acts on a metal film, so that the metal film generates surface plasmon resonance, the probe light path senses variation of the refraction index of the liquid interface at a surface plasmon resonance position, a phase position of the probe light is changed, the system further generates Michelson interference, light intensity interference value is acquired, and a contrast image is generated according to the light intensity interference value. According to the photo-acoustic microscopic imaging system and method, a system detection bandwidth is improved by the aid of a strong local effect of tight focusing vector light, and a sensor can improve imaging sensitivity by a phase-type analysis mode, so that the photo-acoustic microscopic imaging system with high signal-to-noise ratio and broad-spectrum detection capability is achieved.

Description

technical field [0001] The invention relates to the technical field of microscopic imaging, in particular to a photoacoustic microscopic imaging system and method based on surface plasmon resonance. Background technique [0002] At present, photoacoustic imaging adopts the method of "photoexcitation-induced photoacoustic signal-photoacoustic detection-image reconstruction". Photoacoustic imaging technology has significant advantages over many traditional imaging technologies in terms of image resolution, contrast, and information volume. [0003] Photoacoustic imaging has the advantages of both optical imaging and acoustic imaging, including optical excitation and acoustic detection. The pulsed laser of the excitation light is used to irradiate the biological tissue, and when the tissue absorbs the light energy, it is heated and expands to form an instantaneous pressure, and a broadband ultrasonic signal is generated. By detecting the photoacoustic signal generated by the ...

AI Technical Summary

Problems solved by technology

[0006] Traditional photoacoustic imaging systems generally use piezoelectric ultrasonic transducers to detect photoacoustic signals. Due to the constraints of the properties of piezoelectric materials, transducers generally have narrow detection bandwidths, such as 20 MHz, and low sensitivity.

The bandwidth of the transducer limits the longitudinal resolution of photoacoustic imaging, which not only affects the accuracy of depth positioning, but also makes the subsequent three-dimensional image detail missing and seriously distorted.

At the same time, the limited detection bandwidth will lose the collected spectral information and cause a saturation effect, which cannot accurately reflect the optical absorption characteristics of the measured substance

The low sensitivity of the transducer can seriously affect the signal-to-noise ratio and reduce the photoacoustic image quality

For example, piezoelectric ultrasonic transducers with a low detection sensitivity of about 800 Pa can cause low contrast and loss of high-frequency information in photoacoustic images

In addition, traditional pressure-based ultrasound transducers are bulky and opaque, limiting the lateral resolution of optical resolution and the ability to combine with other optical microscopy imaging techniques

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