CN117949089A - Coherent optical tomography device and method based on integrated on-chip broad spectrum light source - Google Patents

Abstract

The invention provides a coherent optical tomography device and a method based on an integrated on-chip broad spectrum light source, relating to the technical field of coherent optical tomography, wherein the device comprises: a laser for providing pump laser light; the nonlinear optical chip is used for acquiring nonlinear effect generated by pumping laser to widen the frequency spectrum to form broad-spectrum laser; the laser scanner is used for focusing the broad-spectrum laser onto the object to be detected for scanning and acquiring signal light scattered by the object to be detected; the interferometer is used for carrying out optical interference on the signal light and the broad-spectrum laser to generate interference light; the imaging spectrometer is used for acquiring interference light imaging to form an interference pattern; and the spectrum analyzer is connected with the imaging spectrometer and is used for acquiring the interference pattern extraction depth information to form a tomographic image. The pump laser generates nonlinear effect to generate wide-spectrum laser, which has the advantages of high coherence and wide spectrum, can improve the signal-to-noise ratio and the quality of the chromatographic image, and increases the oscillation period of the interference pattern to improve the depth resolution of the chromatographic image.

Description

Coherent optical tomography device and method based on integrated on-chip broad spectrum light source

Technical Field

The invention relates to the technical field of coherent optical tomography, in particular to a coherent optical tomography device and a method based on an integrated on-chip broad spectrum light source.

Background

The coherent optical tomography technology is widely applied to the fields of biomedicine, industrial detection, fingerprint acquisition and the like. In medical detection, especially for the prevention and diagnosis of ophthalmic diseases, contactless coherent optical tomography is particularly important.

The traditional spectral domain coherent optical tomography (Spectral domain optical coherence tomography) is mainly based on a Super-radiation light-emitting diode (Super-luminescent diodes) light source as an imaging light source, scans an object to be detected by using a low-coherence broad-spectrum light source, converts refractive index information of each depth of the object to be detected into an interference pattern by using an optical interferometer, then carries out Fourier transform on the interference pattern by using a spectrometer to extract depth information, and finally utilizes a computer system to construct the extracted information into a visual three-dimensional tomographic image. Compared with a time domain optical coherence tomography system, the spectral domain coherence tomography system encodes depth information to each wavelength of a wide-spectrum light source, so that the scanning speed is improved, and the spectral domain coherence tomography system is a mainstream scheme of a current commercial coherence optical tomography system.

However, the existing super-radiation light-emitting diode light source has the defect of low coherence, so that the interference pattern generated by the optical interferometer has poor quality, and the problems of limited signal-to-noise ratio, poor imaging quality and the like are caused; meanwhile, the super-radiation light-emitting diode light source also has the defect of narrow frequency spectrum, so that the generated interference pattern has a small oscillation period, the resolution of Fourier transform is limited, and the resolution of longitudinal depth is further limited.

Disclosure of Invention

The invention provides a coherent optical tomography device and a method based on an integrated on-chip broad spectrum light source, which are used for solving the problems of poor imaging quality caused by low coherence of a laser source and limited resolution caused by narrow frequency in the prior art.

The invention provides a coherent optical tomography device based on an integrated on-chip broad spectrum light source, comprising:

A laser for providing pump laser light;

the nonlinear optical chip is used for acquiring nonlinear effect generated by the pump laser to widen the frequency spectrum to form wide-spectrum laser;

the laser scanner is used for focusing the broad-spectrum laser onto an object to be detected for scanning and acquiring signal light scattered by the object to be detected;

The interferometer is used for carrying out optical interference on the signal light and the broad-spectrum laser to generate interference light;

The imaging spectrometer is used for acquiring the interference light imaging to form an interference pattern;

and the spectrum analyzer is connected with the imaging spectrometer and is used for acquiring the interference pattern extraction depth information to form a tomographic image.

According to the coherent optical tomography device based on the integrated on-chip broad spectrum light source, the laser is an optical fiber pulse laser or a free space pulse laser.

According to the coherent optical tomography device based on the integrated on-chip broad spectrum light source, the nonlinear optical chip comprises an optical waveguide and an end surface coupling structure, and the end surface coupling structure is connected with the laser so that pump laser generated by the laser is input to the optical waveguide.

The coherent optical tomography device based on the integrated chip broad spectrum light source, provided by the invention, further comprises a beam expander, wherein the optical waveguide is provided with an input end and an output end, the input end is connected with the end face coupling structure, and the output end is connected with the beam expander.

According to the coherent optical tomography device based on the integrated on-chip broad spectrum light source, the optical waveguide is made of aluminum gallium arsenic material.

According to the coherent optical tomography device based on the integrated on-chip broad spectrum light source, the laser scanner comprises an adjusting mechanism, a focusing lens group and a first reflecting mirror, wherein the focusing lens group and the first reflecting mirror are connected with the adjusting mechanism, broad spectrum laser irradiates on an object to be detected through the focusing lens group and the first reflecting mirror in sequence, the adjusting mechanism is used for adjusting the positions of the focusing lens group and the reflecting mirror, the focusing lens group is used for adjusting the focal distance so as to focus the broad spectrum laser on the object to be detected, and the first reflecting mirror is used for changing the focusing position.

According to the coherent optical tomography device based on the integrated on-chip broad spectrum light source, the optical interferometer comprises a beam splitting prism, a second reflecting mirror and a dispersion compensating prism, the beam splitting prism is used for splitting the broad spectrum laser output by the nonlinear optical chip into a first path of broad spectrum laser and a second path of broad spectrum laser, the first path of broad spectrum laser is transmitted to the laser scanner to form the signal light to return, the second path of broad spectrum laser irradiates the second reflecting mirror to reflect and return, and the returned second path of broad spectrum laser is interfered with the returned signal light to form the interference light after passing through the dispersion compensating prism.

According to the coherent optical tomography device based on the integrated on-chip broad spectrum light source, the imaging spectrometer comprises a light splitting grating and a photosensitive device array, wherein the light splitting grating is used for separating light with different frequencies in the incident interference light, and the photosensitive device array is used for generating the interference pattern according to the light separated by the light splitting grating.

According to the coherent optical tomography device based on the integrated on-chip broad spectrum light source provided by the invention, the spectrum analyzer comprises an electrical spectrum analyzer or a computer connected with the imaging spectrometer.

The invention also provides an imaging method which is applied to the coherent optical tomography device based on the integrated chip broad spectrum light source and comprises the following steps:

introducing pump laser generated by a laser into a nonlinear optical chip to generate broad-spectrum laser;

introducing the broad spectrum laser into a laser scanner, and adjusting the laser scanner to focus the broad spectrum laser on an object to be detected and scan the object to be detected;

The signal light scattered by the object to be detected and the broad spectrum laser are acquired by a laser scanner and are led into an optical interferometer, and the optical interferometer enables the signal light and the broad spectrum laser to interfere to generate interference light;

the interference light is led into an imaging spectrometer, and the imaging spectrometer separates light with different frequencies in the interference light and then images the light to form an interference pattern;

The interference pattern is input to a spectrum analyzer, which fourier-transforms the interference pattern to extract depth information and generates a tomographic image from the depth information.

The coherent optical tomography device and method based on the integrated on-chip broad spectrum light source provided by the invention have at least the following beneficial effects: the pump laser generated by the laser is input into the nonlinear optical chip, and nonlinear effect is generated in the nonlinear optical chip by the pump laser, so that the frequency spectrum of the pump laser is widened to form broad-spectrum laser, and meanwhile, the light of each frequency inherits the good coherence of the pump laser, so that the broad-spectrum laser has the advantages of high coherence and wide frequency spectrum. The laser scanner scans an object to be detected by using broad-spectrum laser, the object to be detected scatters the broad-spectrum laser to form signal light in the scanning process, the laser scanner transmits the signal light to the interferometer, the interferometer simultaneously acquires the broad-spectrum laser to interfere the signal light and the broad-spectrum laser to form interference light, the interference light is transmitted to the imaging spectrometer, the imaging spectrometer sensitively images the interference light to form interference pattern data, the interference pattern data is transmitted to the spectrum analyzer for processing, the spectrum analyzer extracts depth information in the interference pattern, and the depth information of different parts of the object to be detected is acquired along with the scanning, so that a tomographic image is formed. Therefore, the wide-spectrum laser has the advantage of high coherence, can improve the signal-to-noise ratio and the quality of the finally obtained tomographic image, and simultaneously has the advantage of wide frequency spectrum, can increase the oscillation period of the interference pattern and improve the longitudinal depth resolution of the finally obtained tomographic image.

Drawings

In order to more clearly illustrate the invention or the technical solutions of the prior art, the following description will briefly explain the drawings used in the embodiments or the description of the prior art, and it is obvious that the drawings in the following description are some embodiments of the invention, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram of a coherent optical tomography apparatus based on an integrated on-chip broad spectrum light source according to the present invention;

FIG. 2 is a schematic diagram of an optical path between a nonlinear optical chip, a laser scanner, an interferometer, and an imaging spectrometer in one embodiment of a coherent optical tomography apparatus based on an integrated on-chip broad spectrum light source provided by the present invention;

Fig. 3 is a flow chart of an imaging method provided by the invention.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is apparent that the described embodiments are some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

The coherent optical tomography apparatus based on an integrated on-chip broad spectrum light source of the present invention is described below with reference to fig. 1 and 2, including:

a laser 100 for providing pump laser light;

The nonlinear optical chip 200 is used for acquiring nonlinear effect generated by the pump laser to widen the frequency spectrum to form broad-spectrum laser;

the laser scanner is used for focusing the broad-spectrum laser onto an object to be detected for scanning and acquiring signal light scattered by the object to be detected;

The interferometer is used for carrying out optical interference on the signal light and the broad-spectrum laser to generate interference light;

The imaging spectrometer is used for acquiring the interference light imaging to form an interference pattern;

and the spectrum analyzer is connected with the imaging spectrometer and is used for acquiring the interference pattern extraction depth information to form a tomographic image.

By inputting the pump laser generated by the laser 100 to the nonlinear optical chip 200, the pump laser generates nonlinear effects in the nonlinear optical chip 200, so that the frequency spectrum of the pump laser is widened to form broad-spectrum laser, and meanwhile, the light of each frequency inherits the good coherence of the pump laser, so that the broad-spectrum laser has the advantages of high coherence and wide frequency spectrum. The laser scanner scans an object to be detected by using broad-spectrum laser, the object to be detected scatters the broad-spectrum laser to form signal light in the scanning process, the laser scanner transmits the signal light to the interferometer, the interferometer simultaneously acquires the broad-spectrum laser to interfere the signal light and the broad-spectrum laser to form interference light, the interference light is transmitted to the imaging spectrometer, the imaging spectrometer sensitively images the interference light to form interference pattern data, the interference pattern data is transmitted to the spectrum analyzer for processing, the spectrum analyzer extracts depth information in the interference pattern, and the depth information of different parts of the object to be detected is acquired along with the scanning, so that a tomographic image is formed. Therefore, the wide-spectrum laser has the advantage of high coherence, can improve the signal-to-noise ratio and the quality of the finally obtained tomographic image, and simultaneously has the advantage of wide frequency spectrum, can increase the oscillation period of the interference pattern and improve the longitudinal depth resolution of the finally obtained tomographic image.

The optical waveguide in the nonlinear optical chip 200 localizes light at a micro-nano scale and has a small mode volume, so that light can be spatially bound, the interaction between the light and a substance is greatly enhanced, and the frequency spectrum broadening caused by nonlinear optical effects is improved. The method of spectral broadening of light using the nonlinear optical chip 200 has lower power consumption and a wider spectrum than conventional optical methods. The broad spectrum laser is generated by the pump laser and nonlinear optical chip 200 generating strong interactions to generate nonlinear effects, and during the interactions, light with new frequency components is continuously generated, and the light with new frequency components is cascaded to generate light with more frequency components, so as to obtain a light source with a widened frequency spectrum. The coherence of the wide-spectrum light source generated in this way inherits the pump light, so that the light of the whole frequency spectrum has a definite phase relation and has good coherence.

It will be appreciated that there may be a connection between the laser 100, the nonlinear optical chip 200, the laser scanner, the interferometer, and the imaging spectrometer, for example, the laser 100 may be connected to the nonlinear optical chip 200 by an optical fiber, connected by a housing, etc.; the laser can be propagated in space to pass through each device in turn without connection relation, so as to achieve the effect of tomography.

In some embodiments of the invention based on coherent optical tomography devices incorporating on-chip broad spectrum light sources, the lasers are fiber pulsed lasers or free space pulsed lasers.

The laser 100 employs a fiber pulse laser or a spatial pulse laser, which produces a pulsed laser with a shorter pulse width and higher peak power. The short pulse width can realize higher time resolution, is favorable for obtaining finer depth information and resolving a smaller-scale structure, and can better realize energy regulation. The high peak power can make the wide-spectrum laser have stronger propagation capability in the object to be measured, thereby being beneficial to improving the depth resolution, and meanwhile, the high peak power can make the signal light scattered by the object to be measured stronger, thereby being beneficial to improving the signal-to-noise ratio. In this way, the resolution and quality of the finally obtained tomographic image can be improved by using the fiber pulse laser or the space pulse laser to provide the pump laser.

The fiber pulse laser outputs laser to the nonlinear optical chip 200 through the fiber, so that loss of laser propagation can be reduced, and the quality of laser input to the nonlinear optical chip 200 can be improved. The space pulse laser propagates laser to the nonlinear optical chip 200 in space by utilizing excellent linearity of the laser, and device connection is not needed between the space pulse laser and the nonlinear optical chip, so that the space pulse laser is beneficial to being used more conveniently. In some embodiments using a spatially pulsed laser, a conditioning lens is disposed between the spatially pulsed laser and the nonlinear optical chip 200 for conditioning the laser light output by the spatially pulsed laser to space so that the laser light propagating in space can be focused at the input end of the nonlinear optical chip 200.

In some embodiments of the present invention based on coherent optical tomography apparatus incorporating on-chip broad spectrum light sources, the nonlinear optical chip 200 includes an optical waveguide and an end-face coupling structure connected to the laser 100 to input pump laser light generated by the laser 100 to the optical waveguide.

The end surface coupling structure is connected with the laser 100 through end surface coupling of devices such as optical fibers, so that pump laser generated by the laser 100 can be stably input into an internal optical waveguide to generate nonlinear effect to form broad-spectrum laser, and stability is improved.

The optical waveguide is provided with an input end and an output end, the input end is connected with the laser 100 through an end surface coupling structure, and the output end can be output through a prism optical fiber or directly output.

In some embodiments of the present invention, the coherent optical tomography apparatus based on an integrated on-chip broad spectrum light source further comprises a beam expander, wherein the output end of the optical waveguide is connected to the beam expander.

The beam expander is connected with the output end of the optical waveguide, namely the output end of the nonlinear optical chip 200, so that the beam expander can conveniently adjust the diameter of the wide-spectrum laser according to the use requirement, thereby meeting the use requirement and enabling the use to be more flexible and convenient.

In some embodiments of the invention based on coherent optical tomography devices incorporating on-chip broad spectrum light sources, the optical waveguide is made of aluminum gallium arsenide material.

The aluminum gallium arsenide (AlGaAs) material can adjust the band gap structure of the material by adjusting and controlling the proportion of aluminum and gallium, thereby realizing the adjustment and control of optical characteristics, being convenient for the performance design of the optical waveguide in the nonlinear optical chip 200, having excellent optical performance, such as high refractive index, being beneficial to improving the transmission performance of laser in the optical waveguide and reducing the loss of laser transmission.

The pump light is input into the low-loss AlGaAs optical waveguide in the nonlinear optical chip, and after the power of the pump light exceeds the threshold value of the nonlinear effect, the nonlinear optical effects such as four-wave mixing, stimulated Raman scattering and the like occur due to the third-order nonlinear effect of the AlGaAs material optical waveguide, so that the original pulse light cascade generates new frequency components.

In some embodiments of the present invention, the nonlinear optical chip 200 may be obtained by: growing an aluminum oxide film on a silicon dioxide substrate through atomic layer deposition, transferring the aluminum gallium arsenic film to the aluminum oxide film through bonding, spin-coating deep ultraviolet exposure glue, transferring a preset optical waveguide shape to the exposure glue through a deep ultraviolet photoetching machine, developing, forming an optical waveguide through ion beam etching treatment, removing the exposure glue, and packaging to form the nonlinear optical chip 200.

Referring to fig. 1 and 2, in some embodiments of the coherent optical tomography apparatus based on an integrated on-chip broad spectrum light source of the present invention, the laser scanner includes an adjusting mechanism, a focusing lens group 410 and a first reflecting mirror 420, both connected to the adjusting mechanism, the broad spectrum laser irradiates the object to be measured sequentially through the focusing lens group 410 and the first reflecting mirror 420, the adjusting mechanism is used for adjusting the pose of the focusing lens group 410 and the reflecting mirror, the focusing lens group 410 is used for adjusting the focal distance to focus the broad spectrum laser on the object to be measured, and the first reflecting mirror 420 is used for changing the focal position.

The broad spectrum laser is transmitted through the focusing lens group 410 to achieve focusing effect, then irradiates on the first reflecting mirror 420 to generate reflection, and finally focuses and irradiates on the object to be measured. The focusing lens group 410 comprises a plurality of lenses, and the adjusting structure is connected with at least one lens to adjust the distance between the adjacent lenses, so as to adjust the focal distance, and enable the broad-spectrum laser to focus on objects to be measured with different distances. The broad-spectrum laser is emitted from the focusing lens group 410, reflected by the first reflecting mirror 420 and then irradiates on the object to be detected, and the adjusting mechanism adjusts the deflection angle of the first reflecting mirror 420, so that the focusing point can be moved, namely the focusing position is changed, and the scanning of the object to be detected is realized.

The adjusting mechanism may include an embodiment of a lead screw motor and a stepping motor, where the lead screw motor is connected with the focusing lens group 410 to drive at least one lens to move linearly, so as to implement a function of adjusting a focal distance, and the stepping motor is connected with the first reflecting mirror 420 to drive the first reflecting mirror 420 to deflect, so that the characteristic that the stepping motor can accurately control a rotation angle is utilized to accurately control a deflection angle of the first reflecting mirror 420, thereby achieving an effect of electrically adjusting the focusing lens group 410 and the first reflecting mirror 420. The adjusting mechanism may also be an embodiment including a sliding rail, a sliding block and a rotating shaft, wherein the sliding block disposed on the sliding rail is connected with the focusing lens group 410, and the rotating shaft is connected with the first reflecting mirror 420, so as to achieve the purpose of adjusting the focusing lens group 410 and the first reflecting mirror 420 manually.

Referring to fig. 1 and 2, in some embodiments of the coherent optical tomography apparatus based on an integrated on-chip broad spectrum light source of the present invention, the optical interferometer includes a beam splitter prism 310, a second mirror 320, and a dispersion compensating prism 330, and the beam splitter prism 310 is configured to split the broad spectrum laser light output by the nonlinear optical chip 200 into a first broad spectrum laser light and a second broad spectrum laser light, where the first broad spectrum laser light is transmitted to the laser scanner to form the signal light return, and the second broad spectrum laser light irradiates the second mirror 320 to reflect and return, and the returned second broad spectrum laser light interferes with the returned signal light to form the interference light after passing through the dispersion compensating prism 330.

The broad spectrum laser output by the nonlinear optical chip 200 irradiates on the beam splitting prism 310, the beam splitting prism 310 divides the broad spectrum laser into a first path of broad spectrum laser and a second path of broad spectrum laser, the first path of broad spectrum laser is transmitted to the laser scanner as scanning light, the first path of broad spectrum laser irradiates on an object to be detected after passing through the focusing lens group 410 and the first reflecting mirror 420, and signal light scattered by the object to be detected returns through the first reflecting mirror 420 and the focusing lens group 410. Meanwhile, the second broad spectrum laser irradiates on the second reflecting mirror 320 to be reflected back and passes through the dispersion compensating prism 330 when returning, and the second broad spectrum laser is used as reference light to interfere with the signal light to form interference light. Because the propagation depth of the light with different frequencies in the object to be measured is different, namely the propagation optical path of the light with different frequencies in the signal light is different, when the light with different frequencies interferes with the reference light, namely the second broad spectrum laser, the light with different frequencies has different interference effects, the depth of the object to be measured can be reflected according to the interference effects, and the interference light can be understood to have the depth information of the object to be measured.

Considering that in the process of scanning an object to be detected by laser, a first path of broad spectrum laser irradiates the object to be detected, when the object to be detected scatters the first path of broad spectrum laser to form signal light, the influence on the optical path of the signal light caused by the chromatic dispersion problem is present, and the accuracy of depth reflection is reduced. Therefore, the dispersion compensation prism 330 is provided to perform dispersion compensation on the reference light, namely the second-path broad spectrum laser, so as to reduce the influence of the optical path difference caused by dispersion when the signal light interferes with the second-path broad spectrum laser, namely the influence of dispersion when interference is reduced, thereby being beneficial to improving the accuracy of the interference light for reflecting the depth information of the object to be measured and further enabling the finally obtained tomographic image to be more accurate.

In some embodiments of the present invention, the second broad spectrum laser light may pass through the dispersion compensating prism 330, then strike the second mirror 320, and also pass through the dispersion compensating prism 330 when reflected back from the second mirror 320.

Referring to fig. 1 and 2, in some embodiments of the present invention based on a coherent optical tomography apparatus incorporating an on-chip broad spectrum light source, the imaging spectrometer includes a light splitting grating 510 for separating light of different frequencies from the incident interference light, and an array of photosensitive devices 520 for generating an interference pattern from the light separated by the light splitting grating 510.

When the interference light passes through the light-splitting grating 510, the light-splitting grating 510 splits the light based on the frequency of the light, and irradiates the light to the corresponding areas of the light-sensing device array 520, respectively, and the light-sensing device array 520 generates corresponding interference pattern data. Accordingly, the light with different frequencies in the interference light is separated by the light-splitting grating 510, so that the interference of the light with different frequencies can be reduced, and the depth information can be extracted from the interference pattern more easily.

The photosensitive device array 520 may be an embodiment including a device having a photosensitive function such as CMOS, CCD, or the like.

In some embodiments of the invention based on a coherent optical tomography apparatus integrated with an on-chip broad spectrum light source, the spectrum analyzer comprises an electrical spectrum analyzer or computer connected to the imaging spectrometer.

The electrical spectrum analyzer and the computer are connected with the photosensitive device array 520 in the imaging spectrometer to acquire interference pattern data for Fourier transform processing, acquire spectrum information of the interference pattern, and extract depth information of the object to be detected according to the intensity corresponding to the frequency in the spectrum information because the interference effect corresponding to the light with different frequencies corresponds to the depth of the object to be detected. By combining depth information corresponding to each focusing point in the scanning process, a tomographic image can be generated, and the effect of tomographic imaging is achieved.

The depth information comprises the depth of the object to be detected and refractive index information in the depth direction, and a tomographic image is generated according to the depth of different focusing points and the refractive index difference in the depth direction.

Referring to fig. 3, the present invention further provides an imaging method applied to the coherent optical tomography device based on the integrated on-chip broad spectrum light source, including:

S210: introducing pump laser generated by a laser into a nonlinear optical chip to generate broad-spectrum laser;

s220: introducing the broad spectrum laser into a laser scanner, and adjusting the laser scanner to focus the broad spectrum laser on an object to be detected and scan the object to be detected;

S230: the signal light scattered by the object to be detected and the broad spectrum laser are acquired by a laser scanner and are led into an optical interferometer, and the optical interferometer enables the signal light and the broad spectrum laser to interfere to generate interference light;

S240: the interference light is led into an imaging spectrometer, and the imaging spectrometer separates light with different frequencies in the interference light and then images the light to form an interference pattern;

S250: the interference pattern is input to a spectrum analyzer, which fourier-transforms the interference pattern to extract depth information and generates a tomographic image from the depth information.

By introducing the high coherence laser light generated by the laser 100 as pump laser light to the nonlinear optical chip 200, the pump laser light generates a nonlinear effect in the nonlinear optical chip 200 to widen the frequency spectrum, forming a broad-spectrum laser light having the advantages of high coherence and a broad frequency spectrum. The broad spectrum laser is led into a laser scanner, specifically, a first path of broad spectrum laser formed after the broad spectrum laser is split by a beam splitter prism 310 in the interferometer, the first path of broad spectrum laser also has the advantages of high coherence and wide frequency spectrum, the laser scanner scans an object to be detected by using the first path of broad spectrum laser, and signal light formed by scattering the object to be detected under the action of the first path of broad spectrum laser returns to the interferometer through the laser scanner. In the interferometer, the signal light interferes with the second-path broad-spectrum laser formed after the light is split to form interference light, and the interference light can reflect the depth information of the object to be measured. The light splitting grating 510 in the imaging spectrometer separates and irradiates the light with different frequencies in the interference light on the photosensitive device array 520, and the photosensitive device array 520 generates interference pattern data through photosensitive imaging and transmits the interference pattern data to the spectrum analyzer. The spectrum analyzer team interference pattern data is subjected to Fourier transform and other processing, depth information is extracted, and the depth information corresponding to different focusing points in the scanning process is combined to generate a tomographic image, so that the tomographic imaging effect is achieved.

Therefore, the signal to noise ratio can be improved by utilizing the advantage of high coherence of the broad-spectrum laser, the quality of the obtained tomographic image is improved, and the oscillation period of the interference pattern is increased by utilizing the advantage of the spectral width of the broad-spectrum laser, so that the longitudinal depth resolution of the tomographic image is improved.

In the description of the present invention, it should be understood that the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.

In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and are not limiting; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims (10)

1. A coherent optical tomography apparatus based on an integrated on-chip broad spectrum light source, comprising:

A laser for providing pump laser light;

the nonlinear optical chip is used for acquiring nonlinear effect generated by the pump laser to widen the frequency spectrum to form wide-spectrum laser;

the laser scanner is used for focusing the broad-spectrum laser onto an object to be detected for scanning and acquiring signal light scattered by the object to be detected;

The interferometer is used for carrying out optical interference on the signal light and the broad-spectrum laser to generate interference light;

The imaging spectrometer is used for acquiring the interference light imaging to form an interference pattern;

and the spectrum analyzer is connected with the imaging spectrometer and is used for acquiring the interference pattern extraction depth information to form a tomographic image.

2. A coherent optical tomography device based on an integrated on-chip broad spectrum light source as claimed in claim 1, characterized in that: the laser is an optical fiber pulse laser or a free space pulse laser.

3. A coherent optical tomography device based on an integrated on-chip broad spectrum light source as claimed in claim 1, characterized in that: the nonlinear optical chip comprises an optical waveguide and an end surface coupling structure, and the end surface coupling structure is connected with the laser to enable pump laser generated by the laser to be input into the optical waveguide.

4. A coherent optical tomography device based on an integrated on-chip broad spectrum light source as claimed in claim 3, characterized in that: the optical waveguide is provided with an input end and an output end, the input end is connected with the end face coupling structure, and the output end is connected with the beam expander.

5. A coherent optical tomography device based on an integrated on-chip broad spectrum light source as claimed in claim 3, characterized in that: the optical waveguide is made of an AlGaAs material.

6. A coherent optical tomography device based on an integrated on-chip broad spectrum light source as claimed in claim 1, characterized in that: the laser scanner comprises an adjusting mechanism, a focusing lens group and a first reflecting mirror, wherein the focusing lens group and the first reflecting mirror are connected with the adjusting mechanism, the broad-spectrum laser sequentially passes through the focusing lens group and the first reflecting mirror to irradiate an object to be measured, the adjusting mechanism is used for adjusting the positions and the postures of the focusing lens group and the reflecting mirror, the focusing lens group is used for adjusting the focal distance so as to focus the broad-spectrum laser on the object to be measured, and the first reflecting mirror is used for changing the focusing position.

7. A coherent optical tomography device based on an integrated on-chip broad spectrum light source as claimed in claim 1, characterized in that: the optical interferometer comprises a beam splitting prism, a second reflecting mirror and a dispersion compensating prism, wherein the beam splitting prism is used for dividing the broad spectrum laser output by the nonlinear optical chip into a first path of broad spectrum laser and a second path of broad spectrum laser, the first path of broad spectrum laser is transmitted to the laser scanner to form signal light for return, the second path of broad spectrum laser irradiates the second reflecting mirror to be reflected and returned, and the returned second path of broad spectrum laser is interfered with the returned signal light after passing through the dispersion compensating prism to form interference light.

8. A coherent optical tomography device based on an integrated on-chip broad spectrum light source as claimed in claim 1, characterized in that: the imaging spectrometer comprises a light splitting grating and a photosensitive device array, wherein the light splitting grating is used for separating light with different frequencies in the incident interference light, and the photosensitive device array is used for generating the interference pattern according to the light separated by the light splitting grating.

9. A coherent optical tomography device based on an integrated on-chip broad spectrum light source as claimed in claim 1, characterized in that: the spectrum analyzer comprises an electrical spectrum analyzer or a computer connected to the imaging spectrometer.

10. Imaging method, characterized in that it is applied to a coherent optical tomography device based on an integrated on-chip broad spectrum light source according to any one of claims 1 to 9, comprising:

introducing pump laser generated by a laser into a nonlinear optical chip to generate broad-spectrum laser;

introducing the broad spectrum laser into a laser scanner, and adjusting the laser scanner to focus the broad spectrum laser on an object to be detected and scan the object to be detected;

The signal light scattered by the object to be detected and the broad spectrum laser are acquired by a laser scanner and are led into an optical interferometer, and the optical interferometer enables the signal light and the broad spectrum laser to interfere to generate interference light;

the interference light is led into an imaging spectrometer, and the imaging spectrometer separates light with different frequencies in the interference light and then images the light to form an interference pattern;

The interference pattern is input to a spectrum analyzer, which fourier-transforms the interference pattern to extract depth information and generates a tomographic image from the depth information.