阅读说明：本技术 一种基于光纤超透镜的稀土离子上转换光谱高效测量系统 (Rare earth ion up-conversion spectrum efficient measurement system based on optical fiber superlens ) 是由 王杰 韩迎东 程振洲 刘铁根 胡浩丰 万浩然 李凡 杨佳麒 于 2019-10-04 设计创作，主要内容包括：本发明属于无机纳米材料光谱探测领域,涉及一种基于光纤超透镜的稀土离子上转换光谱高效测量系统的设计,该系统由激光器、端面刻有超透镜的传输激发光的光纤、放置稀土掺杂上转换纳米颗粒的可开合微腔、对应于激发光波长的带通滤光片、对应于激发光波长的低通滤光片、端面刻有超透镜的传输发射光的多模光纤和光谱仪组成。相比于传统上转换光谱测量系统,本发明提供的测量系统可以将入射激发光聚焦在微腔中的上转换纳米颗粒上,提高入射在纳米颗粒上的激发光强度,进而提高其上转换发光强度,同时,纳米颗粒的发射光经多模光纤端面的超透镜收集进入多模光纤,实现高效率的荧光收集。这样便可极大的提升稀土离子上转换光谱的测量效率。(The invention belongs to the field of inorganic nano material spectrum detection, and relates to a design of a rare earth ion up-conversion spectrum efficient measurement system based on an optical fiber superlens. Compared with the traditional upconversion spectrum measurement system, the measurement system provided by the invention can focus incident exciting light on upconversion nano particles in the microcavity, improve the intensity of the exciting light incident on the nano particles, further improve the upconversion luminous intensity, and meanwhile, the emitted light of the nano particles enters the multimode fiber through the superlens on the end face of the multimode fiber, so that high-efficiency fluorescence collection is realized. Therefore, the measurement efficiency of the rare earth ion up-conversion spectrum can be greatly improved.)

1. The utility model provides a high-efficient measurement system of rare earth ion up-conversion spectrum based on super lens of optic fibre which characterized in that: the device comprises a laser, an optical fiber which is provided with a superlens on the end face and transmits exciting light, an openable microcavity for placing rare earth doped up-conversion nanoparticles, a band-pass filter corresponding to the wavelength of the exciting light, a low-pass filter corresponding to the wavelength of the exciting light, a multimode optical fiber which is provided with a superlens on the end face and transmits emitted light, and a spectrometer, wherein the seven parts are total;

exciting light emitted from a laser is transmitted by an optical fiber which is engraved with a super lens on the end face and transmits the exciting light, and the exciting light is focused at the position of the upconversion nanoparticles by utilizing the focusing effect of the super lens on the end face of the optical fiber to excite the upconversion nanoparticles to generate upconversion luminescence; and then, by utilizing the focusing action of a superlens positioned on the end face of the multimode fiber, the emitted light generated by the up-conversion nano particles is efficiently collected and enters the multimode fiber with the superlens carved on the end face to transmit the emitted light, and then the emitted light is transmitted through the multimode fiber with the superlens carved on the end face to enter a handheld spectrometer for subsequent spectral analysis and display, so that the efficient measurement of the up-conversion spectrum of the nano particles is realized.

2. The system for efficient measurement of rare earth ion up-conversion spectra based on fiber-optic superlens of claim 1, wherein: the emission center wavelength of the laser is the wavelength that is capable of exciting the rare earth doped upconversion nanoparticles to produce upconversion luminescence, including excitation light wavelengths near 808nm, near 980nm, and near 1550 nm.

3. The system for efficient measurement of rare earth ion up-conversion spectra based on fiber-optic superlens of claim 1, wherein: the superlens is composed of periodic microstructures, and realizes focusing of incident exciting light.

4. The system for efficient measurement of rare earth ion up-conversion spectra based on fiber-optic superlens of claim 1, wherein: the band-pass filter corresponding to the wavelength of the exciting light is placed between the optical fiber which is etched with the superlens on the end face and transmits the exciting light and the rare earth doped up-conversion nano particles.

5. The system for efficient measurement of rare earth ion up-conversion spectra based on fiber-optic superlens of claim 1, wherein: a low pass filter corresponding to the wavelength of the excitation light is placed between the rare earth doped upconversion nanoparticles and the multimode optical fiber transmitting the emission light, the end face of which is engraved with a superlens.

6. The system for efficient measurement of rare earth ion up-conversion spectra based on fiber-optic superlens of claim 1, wherein: the superlens is composed of periodic microstructures, and can realize the chromatism-free focusing at the same position for incident parallel light with the wavelength range of 300nm-1200 nm.

7. The system for efficient measurement of rare earth ion up-conversion spectra based on fiber-optic superlens of claim 1, wherein: the rare earth doped up-conversion nano particles to be measured are placed in the openable microcavity, and the horizontal distances from the single-mode fiber end face super lens and the multi-mode fiber end face super lens for transmitting exciting light are respectively the focal lengths of the end face super lens and the multi-mode fiber end face super lens of the fiber for transmitting exciting light.

8. The system for efficient measurement of rare earth ion up-conversion spectrum based on fiber-optic superlens according to claim 3 or 6, wherein: the superlens for focusing incident excitation light and shaping emergent fluorescence is engraved on the chip, and then the chip is respectively attached to the end faces of the optical fiber for transmitting excitation light and the multimode optical fiber for transmitting emitted light.

Technical Field

The invention belongs to the field of inorganic nano material spectrum detection, and particularly relates to a rare earth ion up-conversion spectrum efficient measurement system based on an optical fiber superlens.

Background

The rare earth doped up-conversion nanoparticles can convert low-energy near-infrared pump light into high-energy visible light or ultraviolet light for emission through the interaction between exciting light and doped ions, namely, generate so-called up-conversion luminescence. In recent years of research, rare earth doped up-conversion nanoparticles have received great attention due to their excellent optical properties such as abundant emission wavelengths, sharp emission peaks, low background fluorescence signals, long luminescence lifetime, and high fluorescence stability. The excellent optical characteristics also enable the rare earth doped up-conversion nanoparticles to be very suitable for the fields of fluorescence anti-counterfeiting, three-dimensional display, biological imaging, photodynamic therapy and the like.

In the research on the rare earth doped up-conversion nanoparticle luminescence mechanism and application, the detection of the rare earth ion up-conversion spectrum is important. The spectral measurement system is the most direct device for obtaining the luminescence spectrum, and the up-conversion luminescence characteristics of the rare earth ions can be obtained from the luminescence spectrum, so that the corresponding luminescence mechanism and the luminescence process can be researched through the luminescence characteristics. Therefore, the measurement efficiency of the spectral measurement system directly determines the accuracy of the obtained experimental data. The systems commonly used for rare earth ion up-conversion spectrum measurement at present can be divided into two types according to the size: the first type is a large-volume table spectrometer externally connected with an excitation light source, and a sample bin, a diffraction grating, a collimating lens and a detector are integrated in the table spectrometer. When the device is used, a sample is placed in the sample bin, appropriate exciting light is selected, and the luminescence spectrum test of the sample can be performed after parameters are reasonably set. The second type is a small-sized hand-held fiber optic spectrometer equipped with an excitation light source, which consists of an incident multimode fiber, a diffraction grating, a collimating lens and a detector, and collects the emitted light of a sample using the fiber. On one hand, the first desktop spectrum testing system is large in size and cannot meet the requirements of a portable miniaturized spectrometer. On the other hand, the up-conversion luminescence quantum yield of rare earth ions is low, typically less than 5%. Therefore, when the up-conversion luminescence spectrum of the rare earth ions is measured, the efficiency of the test system is often required to be high enough, and especially when the up-conversion luminescence spectrum of the single-particle nanoparticles is measured, the second handheld device cannot meet the measurement requirement generally due to the fact that the number of particles is small and the total luminescence intensity is very weak. Therefore, how to simultaneously satisfy the volume miniaturization and high efficiency test of the spectrometer is a difficult problem faced by the current upconversion nanoparticle spectrum test.

In previous studies, researchers have generally performed the measurement of rare earth ion up-conversion spectra directly using one of the two spectral measurement systems, and there has been only a small amount of design and research on the up-conversion spectral measurement system. 2013, Liang Li et al in measuring Er under different magnetic fields ³⁺:YVO ₄When the up-conversion luminescence characteristics of the single crystal are realized, an up-conversion spectrum measuring system based on the optical fiber is provided. The measuring system consists of a laser, a lens group, a prism, a multimode optical fiber, a spectrometer and a sample chamber with a magnet. The excitation light and the emission light of the sample are transmitted through the same multimode optical fiber. When excited by excitation light, a sample in a magnetic field produces up-converted luminescence, after which the emitted light is transmitted through a multimode fiber and prisms and lenses to a spectrometer for spectroscopic measurements at different magnetic fields (Optics Letters,38,3754,2013). In the same year, Dayong Jin et al also proposed an optical fiber-based up-conversion spectroscopic measurement system when studying how to overcome concentration quenching by using ultra-high excitation power. The measuring system consists of a laser, an attenuator, a lens group, a dichroic mirror, a multimode fiber, a spectrometer and a cuvette. Similar to the design of Liang Li et al, the excitation and emission light in this measurement system are both transmitted by the same multimode fiber. But do notThe spectral measurement efficiency of the system is greatly improved due to the combination of the lens array and the use of a spectrometer with higher sensitivity (Nature Nanotechnology,8,729,2013). In 2019, when the Xiaogang Liu et al research on the realization of up-conversion luminescence amplification through a dielectric superlens modulation effect, an up-conversion spectrum measurement system based on a transparent dielectric microbead array is provided. The measurement system consists of a laser, a fluorescence microscope, a fiber spectrometer and a transparent dielectric microbead array. With the bidirectional wavefront modulation effect of the transparent dielectric beads, up-conversion spectroscopy measurements under excitation with excitation power below a threshold can be achieved (Nature Communications,10,1391,2019). However, no design research has been reported so far for a rare earth ion up-conversion spectrally efficient measurement system based on a fiber-optic superlens.

In the patent aspect, in 2017, people such as jones and the like at Qinghua university have invented a spectral measurement system and a measurement method, the system comprises a micro spectrometer, a standard reflecting plate and a mobile terminal, spectral data of the same standard can be obtained in different acquisition environments, the measurement applicability is improved, the accuracy and the stability of the spectral data are ensured, and a Chinese invention patent is applied (201710054763.8). 2018, Zhaoxiang Wei of southeast university, et al invented a fluorescence correlation spectroscopy measurement system, which utilizes a tapered optical fiber to limit the excitation light in the volume of the fly-lift, and utilizes an optical fiber to collect fluorescence signals to perform time-dependent photon counting, thereby obtaining fluorescence correlation spectra, and applied for Chinese invention patent (201811382587.1). In 2019, the continental Asian forest, China science and technology university, and the like invented a terahertz time-domain spectroscopy measurement system and method, the measurement system comprises a terahertz optical device, a cavity device and a vacuum device, the measurement system and method can successfully eliminate the interference of water vapor on background signals in the terahertz time-domain spectroscopy measurement process, no additional drying gas or drying unit is needed, and the Chinese invention patent is applied (201910179165.2). In the above patents relating to the design of the spectrum measuring system, the design of the rare earth ion up-conversion spectrum efficient measuring system based on the fiber super lens is not protected.

In summary, in recent years, although the spectrum test system and the spectrum test technology are continuously developed, the application range is also continuously expanded, and the spectrum test process of various materials is involved. However, the design of a high-efficiency measurement system for rare earth ion up-conversion spectroscopy based on a fiber-optic superlens has not been reported, and a patent related to the design is not published. In the method, the design of a rare earth ion up-conversion spectrum efficient measurement system based on a fiber super lens is provided by combining the development trends of low power consumption and miniaturization of the spectrum measurement system. Compared with a traditional spectrum measurement system, the optical fiber superlens is introduced, so that the whole spectrum measurement system has higher measurement efficiency on the basis of miniaturization, and an optical filter is added between the emergent end face of the laser and the sample and between the sample and the incident multimode optical fiber end face of the optical fiber spectrometer, so that the accuracy and the reliability of the spectrum measurement system are further improved. In addition, the measurement system has the advantages of low working energy consumption, high precision, low excitation light power threshold value, good portability and the like, and is expected to be applied to various up-conversion luminescence measurements as a novel up-conversion luminescence measurement system.

Disclosure of Invention

The invention aims to provide a design of a rare earth ion up-conversion spectrum efficient measurement system based on a fiber superlens.

The invention provides a rare earth ion up-conversion spectrum efficient measurement system based on an optical fiber superlens, which is characterized in that: the device comprises a laser, an optical fiber which is provided with a superlens on the end face and transmits exciting light, an openable microcavity which is used for placing rare earth doped up-conversion nano particles, a band-pass filter corresponding to the wavelength of the exciting light, a low-pass filter corresponding to the wavelength of the exciting light, a multimode optical fiber which is provided with a superlens on the end face and transmits emitted light and a spectrometer, wherein the seven parts are total.

Further, in the system for efficient measurement of rare earth ion up-conversion spectrum based on the fiber-optic superlens, the emission center wavelength of the laser may be a wavelength capable of exciting the rare earth-doped up-conversion nanoparticles to generate up-conversion luminescence, including excitation light wavelengths near 808nm, near 980nm and near 1550 nm.

Furthermore, in the efficient measurement system for the rare earth ion up-conversion spectrum based on the optical fiber superlens, the superlens carved on the end face of the optical fiber for transmitting the exciting light is composed of the periodic microstructure, so that the focusing of the incident exciting light can be realized.

Further, in the efficient measurement system for rare earth ion up-conversion spectrum based on the fiber-optic superlens, the band-pass filter corresponding to the wavelength of the excitation light must be placed between the fiber with the superlens on the end surface for transmitting the excitation light and the rare earth-doped up-conversion nanoparticles.

Further, in the efficient measurement system for rare earth ion up-conversion spectrum based on the fiber super lens, a low-pass filter corresponding to the wavelength of the excitation light must be placed between the rare earth doped up-conversion nanoparticles and the multimode fiber for transmitting the emission light, the end face of which is engraved with the super lens.

Furthermore, in the efficient measurement system for the rare earth ion up-conversion spectrum based on the optical fiber superlens, the superlens engraved on the end face of the multimode optical fiber for transmitting emitted light consists of periodic microstructures, and can realize the same position focusing without chromatic aberration for incident parallel light with the wavelength range of 300nm-1100 nm.

Furthermore, in the efficient measurement system for the rare earth ion up-conversion spectrum based on the fiber super lens, the rare earth doped up-conversion nanoparticles to be measured are placed in the openable microcavity, and the horizontal distances from the end face super lens of the fiber for transmitting the excitation light and the end face super lens of the multimode fiber are respectively the focal distances from the end face super lens of the fiber for transmitting the excitation light and the end face super lens of the multimode fiber.

Furthermore, the superlens for focusing incident excitation light and shaping emergent fluorescence can also be engraved on the chip, and then the chip is respectively attached to the end faces of the optical fiber for transmitting excitation light and the multimode optical fiber for transmitting emitted light, so as to realize the same effects of focusing incident excitation light and shaping emergent fluorescence.

The invention has the following beneficial effects:

the invention provides a design of a rare earth ion up-conversion spectrum efficient measurement system based on an optical fiber superlens. Compared with the traditional upconversion luminescence measurement system, the measurement system provided by the invention can focus incident exciting light on upconversion nanoparticles in a microcavity through a superlens on the end face of an optical fiber under the condition of the same output power of the laser, so that the intensity of the exciting light incident on the nanoparticles is improved, and the upconversion luminescence intensity of the nanoparticles is further improved. Then the emitted light of the nano particles is collected by a chromatic aberration-free super lens on the end face of the multimode optical fiber and enters the multimode optical fiber, so that high-efficiency fluorescence collection is realized. Therefore, the measurement efficiency of the luminescence of the rare earth doped up-conversion nanoparticles can be greatly improved. In addition, the measurement system has the advantages of low working energy consumption, small overall system size, portability and the like, and is expected to be applied to various up-conversion luminescence measurements as a novel up-conversion luminescence measurement system.

Drawings

FIG. 1 shows a NaYF based on fiber superlens in embodiment 1 of the present invention ₄A design drawing of a high-efficiency measurement system for up-conversion spectra on 20% Yb/2% Er nano particles;

FIG. 2 shows a NaYF based on fiber superlens in embodiment 1 of the present invention ₄A spectral measurement light path diagram of a 20% Yb/2% Er nanoparticle up-conversion spectral efficient measurement system;

in the figure: 1. a 980nm near infrared laser; 2. 980nm single-mode optical fibers with superlenses on the end faces; 3. placing an openable microcavity of the upconverting nanoparticle; 4. a 980nm bandpass filter; 5. a 980nm low-pass filter; 6. the end face of the multimode fiber is provided with a superlens for transmitting emitted light; 7. a handheld spectrometer; 8. a superlens at the end face of the single-mode optical fiber; 9. a superlens located at an end face of the multimode optical fiber; 10. up-converting the nanoparticles.

Detailed Description

The invention will be further described with reference to the accompanying drawings and examples. These examples are to be construed as merely illustrative and not limitative of the remainder of the disclosure in any way whatsoever. After reading the disclosure of the present invention, various changes or modifications made based on the principle of the present invention also fall within the scope of the present invention as defined in the appended claims.