Optical sensing system and sensing testing method

Abstract

The invention discloses an optical sensing system. The optical sensing system comprises a monochromatic collimating light source, an optical sensor and a photoelectric detector; the photoelectric detector comprises a rotatable semiconductor substrate layer and a metal or metal-like material film covering the semiconductor substrate; the light facing surface of the photoelectric detector forms an optical grating; and the optical sensor and the photoelectric detector share the optical grating. The invention further discloses a sensing testing method using the optical sensing system. The sensing testing method comprises the following steps that: the monochromatic incident light source is started to irradiate; the semiconductor substrate layer is rotated, so that a resonance angle theta1 is obtained; an object to be detected is introduced, the semiconductor substrate layer is rotated, so that a resonance angle theta2 for irradiating the object to be tested is obtained; and the refractive index of the object to be tested can be obtained based on the change of the resonance angle theta2 relative to the resonance angle theta1. With the optical sensing system and sensing testing method of the invention adopted, high-sensing sensitivity, narrow-resonance peak line width and large-working wavelength range electric signal output can be realized, and the refractive index of gas or liquid can be measured with no extra spectrographs or photoelectric detectors required.

Description

technical field [0001] The invention relates to the field of optical sensing technology and sensors, in particular to an optical refraction index sensing system and a sensing test method that scans the angle of incident light and outputs it as a direct electrical signal. Background technique [0002] At present, there is an urgent demand for highly sensitive sensors in fields such as biomedicine, environmental monitoring, food safety and even national defense. Optical sensors have the characteristics of high sensitivity, anti-electromagnetic interference, and non-marking, so they have received extensive attention and vigorous development. Generally, optical sensors use optical resonance structures to enhance the sensing performance of the refractive index, and detect changes in the measured object by testing the wavelength shift of the resonance peak. The sensing sensitivity is defined as the wavelength shift of the resonant peak under the condition of the unit refractive i...

AI Technical Summary

Problems solved by technology

[0004] Although these works have achieved the functional integration of light sensing and light detection to a certain extent, they all require photodetector arrays, and they all use macroscopic assembling of light sensing chips and photodetectors. The cell pitch is large, and in sensing imaging applications, it will not work due to the crosstalk between adjacent pixels, which also limits the further miniaturization of the device volume

In addition, the resonant peaks of these sensor chips are very wide, the sensing sensitivity is limited, and their operating wavelength range is limited by the photoelectric response band of the silicon detector, which limits the applicable range of the device

[0005] In 2011, the journal OpticsExpress reported on page 9962, volume 19, an integrated optical sensor that prepared a metal nanopore structure on the surface of a silicon material pn junction photodetector covered with a silicon oxide layer. The measured object on the surface of the nanopore will change The characteristics of transmitted light, thus affecting the light absorption and photovoltage signal output of silicon materials

These have realized the monolithic integration of the sensing structure and the detection structure, and only a single detector is required. However, its working wavelength range is still limited by the transition mechanism between semiconductor bands, and the filtering performance of nanopores is limited by the large refractive index contrast. Severe interference at the bottom, resulting in indistinct resonance peaks, wide resonance peak linewidth, and low transmittance, resulting in small changes in the light absorption rate of the detector, which limits the sensing performance of the device, and the optical power and photocurrent of the voltage type device The linearity is poor, which is not conducive to sensing applications

[0006] It can be seen that although the existing technologies represented by the above examples have obtained optical sensing of electrical signal output, the test systems are relatively complex, and it is difficult to achieve high sensing sensitivity, narrow formant linewidth, and large operating wavelength range coexistence

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