CN111562004B

CN111562004B - Quantum dot light source chip spectrometer without light splitting system and spectrum reconstruction method

Info

Publication number: CN111562004B
Application number: CN202010324658.3A
Authority: CN
Inventors: 王少伟; 尹知沁; 刘清权; 陆卫
Original assignee: Shanghai Institute of Technical Physics of CAS
Current assignee: Shanghai Institute of Technical Physics of CAS
Priority date: 2020-04-23
Filing date: 2020-04-23
Publication date: 2022-12-30
Anticipated expiration: 2040-04-23
Also published as: CN111562004A

Abstract

The invention discloses a quantum dot light source chip spectrometer without a light splitting system and a spectrum reconstruction method. The light source of the invention is composed of a series of quantum dot arrays with different luminous wavelengths, so that the light source has spectral resolution capability, light splitting is not required by any light splitting system, a chip-level spectral instrument can be formed by combining with a photoelectric detector, and even the light source can be directly combined with a mobile phone to form an intelligent mobile phone spectrometer for identifying the components of substances.

Description

Quantum dot light source chip spectrometer without light splitting system and spectrum reconstruction method

Technical Field

The invention relates to the field of spectrum measuring instruments, in particular to a micro spectrometer based on a quantum dot light source chip and a spectrum reconstruction method.

Background

The spectrum is a pattern in which monochromatic light dispersed by a dispersion system (such as a prism and a grating) is sequentially arranged according to the wavelength (or frequency) after the monochromatic light is dispersed by the dispersion system, and is entirely called an optical spectrum. Light may interact with a substance, which interacts with light as a beam of light passes through different chemical substances. In the molecule of the substance, atoms constituting the chemical bond or the functional group are in a constantly oscillating state, and the oscillation frequency thereof corresponds to the oscillation frequency of light. Therefore, when the molecules are irradiated by light, the chemical bonds or functional groups in the molecules can absorb vibration, and different chemical bonds or functional groups have different absorption frequencies and are located at different positions on the spectrum, so that information about what chemical bonds or functional groups are contained in the molecules can be obtained.

The spectrometer is an analytical instrument capable of distinguishing different light wave intensities, can capture substance optical information and analyze molecular structures and chemical compositions, and is widely applied to multiple fields of astronomy, biology, chemistry, medicine, environmental science and the like. However, almost all spectrometers have been made based on dispersive optical splitting systems such as gratings or lenses, and can achieve very high spectral resolution in visible and near infrared bands, but gratings have the disadvantages of complex processing, high cost, vulnerability, and the like, and the longer the optical path required for higher resolution, the larger the corresponding spectrometer volume. In a spectrometer using michelson interference spectroscopy, because a time sequence interferogram of a target spectrum pixel needs to be obtained by controlling the accurate scanning of a movable mirror, and then a spectrum is obtained by using fourier transform, the requirements of the spectrometer on the machining precision of a mechanical structure and the precision of scanning transmission are very strict, so the cost is high, and the spectrometer comprises a moving element, so that the moving distance is longer and the size is larger in order to obtain higher resolution, so the spectrometer has a complex spectroscopic system with a large size, and the microminiaturization of the spectrometer and the popularization and application in daily life are severely limited.

Disclosure of Invention

In view of this, the invention adopts a quantum dot light source without a light splitting system to construct a novel chip-level spectrometer, uses a light-emitting light source chip composed of a series of quantum dots with different light-emitting wavelengths to play the roles of light source and light splitting at the same time, and combines a spectrum reconstruction technology to realize a spectrum detection function, thereby completely removing the traditional light splitting system, and only needing the quantum dot light source chip to be combined with any mobile phone to construct an intelligent spectrometer. The quantum dot light source chip spectrometer disclosed by the invention consists of a quantum dot light source chip 1 and a signal acquisition and processing system 2, a sample to be detected can be placed between the quantum dot light source chip 1 and the signal acquisition and processing system, and transmission or reflection signals of the sample to be detected are acquired, so that the quantum dot light source chip spectrometer is very simple, small, flexible and portable.

The quantum dot light source chip 1 is respectively provided with an excitation light source 11, a quantum dot array 12 and a long wave pass filter 13 from top to bottom.

The excitation light source 11 is a light source for exciting the quantum dots to emit light, and may be an LED or a laser, as long as the wavelength is smaller than the emission wavelength of all the quantum dots of the quantum dot array 12, and all the quantum dots can be excited to emit light.

The quantum dot array 12 is formed by periodically arranging quantum dots 121 with different light-emitting wavelengths on an exciting light transparent substrate 122. The period can be selected between 10 mu m and 1cm according to actual needs; the scale of the device can be set according to the spectral band range and the spectral resolution requirement, and is usually not less than 2 multiplied by 2; since the emission spectrum range of the quantum dots is affected by their materials and sizes, the quantum dot array 12 can be made of different materials with the same size, the same materials with different sizes, or a combination of the two. The quantum dots made of different materials comprise cadmium quantum dots, perovskite quantum dots, indium quantum dots, carbon quantum dots and silicon quantum dots. Because quantum dots with different sizes can emit light within different wavelength narrow bandwidth ranges, the quantum dot array can play both a light source role and a light splitting role, a light splitting system with a complex structure and a large volume is replaced, and the volume of the spectrometer is greatly reduced. In addition, the working wavelength range of the quantum dot light source chip spectrometer can cover the whole visible light and near infrared range by reasonably selecting quantum dots; the resolution is determined by the quantity of quantum dots with different materials and sizes, the more the number of the quantum dots with different materials and sizes is, the higher the resolution is, the types and the number of the quantum dots can be randomly arranged on the substrate 122 according to specific requirements to achieve the purpose of testing, and the method is very flexible and convenient.

The substrate 122 is a substrate capable of transmitting the light emitting wavelength of the excitation light source, and includes optical glass, quartz, and gemstone. The quantum dot array 121 limits and determines the position through a groove array on the substrate, the groove array can be processed by adopting a laser etching method, grooves are etched on the surface of the substrate by using laser beams, and then different quantum dots are respectively transferred to corresponding grooves, so that the method is flexible and convenient; the method can also be realized by photoetching and coating, the quantum dots are limited in the middle after the metal grid bars are coated on the substrate, and the template for constructing the quantum dot array can be produced in a large batch at one time, so that the method is very quick and has low cost.

The long-wave pass filter 13 is a filter through which light in the emission wavelength range of the excitation light source cannot pass but through which light emitted by the quantum dots can efficiently pass, and the transmission spectrum of the filter is as shown in fig. 2, so that the light emitted by the excitation light source is prevented from interfering with the quantum dot emission signal received by the photodetector.

The photoelectric detector and the data acquisition processing system 2 may be composed of a CCD or a CMOS and a corresponding data acquisition processing system. The photoelectric detector needs to be capable of responding to light emitted by the quantum dot light source chip array, and the data acquisition and processing system is matched with the photoelectric detector to process acquired signals and obtain and output a final sample spectrum after spectral reconstruction. The existing mobile phone lens is preferentially adopted as a data acquisition system of the spectrometer, and then a result is calculated by a processor in the mobile phone. The light emitted by the quantum dots can correspond to the pixels of the mobile phone lens one by one, and the method is intelligent and convenient, and can utilize the communication transmission function of the mobile phone to transmit the result in real time and high efficiency. Any smart phone with a lens can be changed into a spectrometer for measuring the material composition around anytime anywhere as long as the smart phone is provided with a quantum dot light source chip, and the smart phone is very small, flexible, cheap and has quite wide market application.

The spectrum of the spectrometer is obtained by a full-rank square matrix spectrum reconstruction technology, and the spectrum reconstruction technology comprises the following steps:

(a) The spectral response of each unit of the quantum dot array is accurately calibrated by using precise spectral equipment (such as a Fourier spectrometer and a grating spectrometer), and the optical response spectrum I of the pixels corresponding to the quantum dots with different sizes is extracted _n In which I _n Is a one-dimensional row vector and represents the luminescent spectrum of quantum dots with the nth size, I _n The size is 1 xn, n represents the sampling number of the quantum dots, and the more the light emission spectra of different quantum dots, the larger n is, the finer the value is, and the higher the resolution is.

(b) All I are _n And forming a square matrix T, wherein each row of the T matrix represents the light response spectrum of the quantum dots with different sizes.

(c) A quantum point light source is irradiated on the surface of a sample, and response values y of detector pixels at different positions are extracted _n Form a column vector Y, where Y _n Representing the nth detector pixelThe response value.

(d) Using the formula F = T ^-1 Y, and reversely solving a sample spectrum F.

Because the whole inversion process adopts a full-rank square matrix inversion method, the reconstruction result has uniqueness and accuracy.

The invention has the following advantages:

1. a series of quantum dot array chips with different light-emitting wavelengths are directly adopted as a light source, so that the light source has spectral resolution capability, a traditional light splitting system with a complex structure and a large volume is removed, the structure of a spectrometer is greatly simplified, and the volume is reduced.

2. The quantum dots integrated on the light source chip can be enough in number, so that the fast reconstruction can be carried out by adopting a square matrix spectrum inversion technology, the resolution is ensured, and simultaneously, the spectrum solution of the equation is unique, so that the original spectrum information of the sample to be detected can be accurately inverted.

3. The existing smart phones are used as a data acquisition and processing system, any smart phone can be changed into an intelligent spectrometer capable of measuring the spectrum at any time and any place as long as a quantum dot light source chip is arranged, the structure is very simple, the cost is low, and the system is particularly suitable for popularization and application in daily life.

The following further description is made in conjunction with the accompanying drawings and the detailed description.

Drawings

Fig. 1 is a schematic diagram of a quantum dot light source chip spectrometer according to all embodiments of the present invention.

Fig. 2 is a long-wavelength pass filter transmission spectrum of all embodiments of the present invention.

Fig. 3 is a transmission spectrum of a quantum dot light source in embodiment 1 of the present invention.

FIG. 4 is a raw transmission spectrum of a sample of example 1 of the present invention.

FIG. 5 is a transmission spectrum of a sample after spectral reconstruction according to example 1 of the present invention.

Fig. 6 is a transmission spectrum of a quantum dot light source in embodiment 2 of the present invention.

FIG. 7 is the raw transmission spectrum of a sample of example 2 of the present invention.

FIG. 8 is a transmission spectrum of a sample after spectral reconstruction in example 2 of the present invention.

Fig. 9 is a transmission spectrum of a quantum dot light source in embodiment 3 of the present invention.

FIG. 10 is the raw transmission spectrum of the sample of example 3 of the present invention.

FIG. 11 is a transmission spectrum of a sample after spectral reconstruction according to example 3 of the present invention.

Fig. 12 is a drawing of a part of quantum dot light sources of embodiment 4 of the present invention, plotted every 8 nm.

FIG. 13 is the raw transmission spectrum of the sample of example 4 of the present invention.

FIG. 14 is the transmission spectrum of the sample after spectral reconstruction in example 4 of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly described below with reference to the drawings in the embodiments of the present invention, and of course, the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.

Example one

In this embodiment, we show the process of reducing the transmission spectrum generated by irradiating a sample with a quantum point light source composed of 32 kinds of materials with different sizes into the spectrum of the sample after spectral reconstruction.

The quantum dot light source structure is shown in fig. 1, wherein: 1 is an LED light source, and an LED lamp with an emission wavelength of 380nm is selected; 2, 32 ZnS quantum point light sources with the same material but different sizes can emit 32 lights with different wavelengths so as to cover a visible light range of 400nm to 431 nm; 3, an optical glass substrate, wherein 32 quantum dots are uniformly placed in a groove by a fixed-point transfer method after the groove is etched on the glass substrate by a laser etching method; 4 is a long-wave pass filter which only allows light with a wavelength of more than 400nm to pass through.

The working process of the quantum dot light source chip spectrometer is as follows:

(1) The optical response spectrum of the quantum dot pixel is calibrated by using a grating spectrometer, and a calibration schematic diagram is shown in fig. 2.

And extracting quantum dot pixel response spectrums corresponding to different channels to form a 32 x 32 square matrix, and naming the matrix as a transmittance matrix T. And each row in T represents 32 discrete values of the response spectrum of the corresponding quantum dot pixel between 400nm and 431 nm.

(2) When a quantum point light source irradiates on a sample, the response values of pixels at different positions of a detector are expressed by a vector as: y = [ Y = ₁ y ₂ y ₃ …y ₃₂ ](ii) a Wherein y is _n Representing the nth detector pixel response value.

The sample spectrum is then: f = T ^-1 Y

The sample spectrum and the reconstructed spectrum are shown in FIG. 4, (1) is a spectrum measured in the detector; (2) is the original spectrum of the sample; and (3) a spectrum obtained after spectral reconstruction. It can be seen that both the original spectrum and the reconstructed spectrum fit very well, so the patent can obtain the spectrum of the sample very well with very simple means.

Example two

The quantum point light source structure is shown in fig. 1, wherein: 1 is an LED light source, and an LED lamp with an emission wavelength of 380nm is selected; 2, the ZnSe quantum point light sources with 32 same materials but different sizes can emit light with 32 different wavelengths so as to cover the visible light range of 400nm to 528 nm; 3, a quartz substrate, wherein 32 quantum dots are uniformly placed in a groove by a fixed-point transfer method after the groove is etched on the glass substrate by a laser etching method; 4 is a long-wave pass filter which only allows light with a wavelength of more than 400nm to pass through.

(1) The optical response spectrum of the quantum dot pixel is calibrated by using a grating spectrometer, and a calibration schematic diagram is shown in fig. 6.

And extracting quantum dot pixel response spectrums corresponding to different channels to form a 32 x 32 square matrix, and naming the matrix as a transmittance matrix T. Each row in T represents 32 discrete values of the response spectrum of the corresponding quantum dot pixel between 400nm and 528 nm.

(2) When a quantum point light source is irradiated on a sample, the response values of pixels at different positions of a detector are expressed by a vector as follows: y = [ Y = ₁ y ₂ y ₃ …y ₃₂ ](ii) a Wherein y is _n Representing the nth detector pixel response value.

The sample spectrum is then: f = T ^-1 Y

The sample spectrum and the reconstructed spectrum are shown in FIG. 7, (1) is a spectrum measured in the detector; (2) is the original spectrum of the sample; and (3) is a spectrum obtained after spectral reconstruction. It can be seen that both the original spectrum and the reconstructed spectrum fit very well, so the patent can obtain the spectrum of the sample very well with very simple means.

EXAMPLE III

In this embodiment, we show the process of reducing the transmission spectrum generated by irradiating a sample with a quantum point light source composed of 100 different materials in different sizes into the spectrum of the sample after spectral reconstruction.

The quantum point light source structure is shown in fig. 1, wherein: 1 is an LED light source, and an LED lamp with the emission wavelength of 480nm is selected; 2, 100 CdSe quantum point light sources with the same material but different sizes can emit 100 lights with different wavelengths so as to cover the visible light range of 510nm to 610 nm; 3, a gem substrate, wherein 100 quantum dots are uniformly placed in a groove by a fixed point transfer method after a groove is etched on a glass substrate by a laser etching method; 4 is a long-wave pass filter which only allows light with a wavelength of more than 500nm to pass through.

(1) The optical response spectrum of the quantum dot pixel is calibrated by using a grating spectrometer, and a calibration schematic diagram is shown in fig. 9.

And extracting quantum dot pixel response spectrums corresponding to different channels to form a 100 x 100 square matrix, and naming the matrix as a transmittance matrix T. Each row in T represents 100 discrete values of the response spectrum of the corresponding quantum dot pixel between 510nm and 610 nm.

(2) When a quantum point light source irradiates on a sample, the response values of pixels at different positions of a detector are expressed by a vector as: y = [ Y) ₁ y ₂ y ₃ …y ₁₀₀ ](ii) a Wherein y is _n Representing the nth detector pixel response value.

The sample spectrum is then: f = T ^-1 Y

The sample spectrum and the reconstructed spectrum are shown in FIG. 10, (1) is a spectrum measured in the detector; (2) is the original spectrum of the sample; and (3) is a spectrum obtained after spectral reconstruction. It can be seen that both the original spectrum and the reconstructed spectrum fit very well, so the patent can obtain the spectrum of the sample very well with very simple means.

Example four

In this example, we show the process of reducing the transmission spectrum generated by irradiating a sample with a quantum dot light source composed of 400 different materials with different sizes into the spectrum of the sample after spectral reconstruction.

The quantum point light source structure is shown in fig. 1, wherein: 1 is an LED light source, and an LED lamp with the emission wavelength of 350nm is selected; 2, a light source formed by mixing 400 different materials and ZnS, cdS, znSe, cdSe, cdTe, pbS and PbSe quantum dots with different sizes can emit 400 lights with different wavelengths so as to cover a visible light range of 380 nm-1180 nm; 3, a glass substrate, wherein 400 quantum dots are uniformly placed in a groove by a fixed-point transfer method after the groove is etched on the glass substrate by a laser etching method; 4 is a long-wave pass filter which only allows light with a wavelength of more than 380nm to pass through.

(1) The photoresponse spectrum of the quantum dot pixels is calibrated by using a grating spectrometer at intervals of 4, and the schematic diagram is shown in fig. 12.

And extracting quantum dot pixel response spectrums corresponding to different channels to form a 400 x 400 square matrix, and naming the matrix as a transmittance matrix T. And each row in T represents 400 discrete values of the response spectrum of the corresponding quantum dot pixel at 380 nm-1180 nm.

(2) When a quantum point light source irradiates on a sample, the response values of pixels at different positions of a detector are expressed by a vector as: y = [ Y = ₁ y ₂ y ₃ …y ₄₀₀ ](ii) a Wherein y is _n Representing the nth detector pixel response value.

The sample spectrum is then:

the sample spectrum and the reconstructed spectrum are shown in FIG. 13, (1) is a spectrum measured in the detector; (2) is the original spectrum of the sample; and (3) is a spectrum obtained after spectral reconstruction. It can be seen that both the original spectrum and the reconstructed spectrum fit very well, so the patent can obtain the spectrum of the sample very well with very simple means.

Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations fall within the scope defined by the appended claims.

Claims

1. The utility model provides a quantum point light source chip spectrum appearance of no beam splitting system, includes quantum point light source chip (1) and photoelectric detector and data acquisition processing system (2), its characterized in that:

the quantum dot light source chip (1) consists of an excitation light source (11), a quantum dot array (12) and a long-wave pass filter (13), wherein the excitation light source (11) is a light source capable of exciting quantum dots to emit light, and the quantum dot array (12) is formed by periodically arranging quantum dots (121) with different light-emitting wavelengths on an excitation light transparent substrate (122);

the quantum dot light source chip (1) after the spectrum calibration is electrified and opened, so that the emitted light irradiates on a sample to be detected, then the corresponding photoelectric detector and the data acquisition and processing system (2) are used for acquiring light signals penetrating through the sample or reflected by the sample, and the spectrum information of the sample to be detected is formed after the spectrum reconstruction.

2. The quantum point light source chip spectrometer without the light splitting system as claimed in claim 1, wherein: the quantum dot array (12) is composed of quantum dots (121) with different light-emitting wavelengths and a substrate (122) transparent to exciting light, wherein the quantum dots (121) are made of different materials with the same size or the same materials with different sizes or the combination of the quantum dots and the substrate, and the quantum dots (121) adopt cadmium quantum dots, perovskite quantum dots, indium quantum dots, carbon quantum dots or silicon quantum dots; the substrate (122) which is transparent to the exciting light is made of glass, precious stone or quartz material.

3. The quantum point light source chip spectrometer without the light splitting system as claimed in claim 1, wherein: the photoelectric detector in the photoelectric detector and data acquisition processing system (2) adopts a CCD or a CMOS, the photoelectric detector and data acquisition processing system (2) adopts a mobile phone, and the mobile phone acquires light emitted by the light source array, converts the light into an electric signal after passing through a sample, and reconstructs a spectrum result through a processor in the mobile phone.

4. The spectral reconstruction method of the quantum dot light source chip spectrometer without the light splitting system, which is based on the claim 1, is characterized by comprising the following steps:

firstly, calibrating the spectral response of a quantum dot light source chip by using precision spectral equipment, extracting response spectra of pixels corresponding to quantum dots with different sizes to form a transmission matrix T, wherein each row in the T represents the spectral dispersion value of the quantum dot pixels with the same size, the number of the rows is consistent with the size number of the quantum dots, the selected waveband of a spectral vector is an effective detection waveband of a device, the number of the spectral vector discrete dots is matched with the size number of the quantum dots, and the transmission matrix T is a full-rank square matrix;

the reconstruction is performed as follows:

F＝T ^-1 Y

wherein, the column vector F is the discrete value of the finally obtained sample spectrum in the selected wave band, namely the spectrum of the sample; the column vector Y is the transmission spectrum detected by the detector.