Gas identification and concentration measurements are important for both understanding and monitoring a variety of phenomena from industrial processes to environmental change.Here a novel mid-IR plasmonic gas sensor w...Gas identification and concentration measurements are important for both understanding and monitoring a variety of phenomena from industrial processes to environmental change.Here a novel mid-IR plasmonic gas sensor with on-chip direct readout is proposed based on unity integration of narrowband spectral response,localized field enhancement and thermal detection.A systematic investigation consisting of both optical and thermal simulations for gas sensing is presented for the first time in three sensing modes including refractive index sensing,absorption sensing and spectroscopy,respectively.It is found that a detection limit less than 100 ppm for CO2 could be realized by a combination of surface plasmon resonance enhancement and metal-organic framework gas enrichment with an enhancement factor over 8000 in an ultracompact optical interaction length of only several microns.Moreover,on-chip spectroscopy is demonstrated with the compressive sensing algorithm via a narrowband plasmonic sensor array.An array of 80 such sensors with an average resonance linewidth of 10 nm reconstructs the CO2 molecular absorption spectrum with the estimated resolution of approximately 0.01 nm far beyond the state-of-the-art spectrometer.The novel device design and analytical method are expected to provide a promising technique for extensive applications of distributed or portable mid-IR gas sensor.展开更多
We have UV-inscribed fiber Bragg gratings （FBGs）, long-period gratings （LPGs） and tilted fiber gratings （TFGs） into mid-IR 2μm range using three common optical fiber grating fabrication techniques （two-beam ho...We have UV-inscribed fiber Bragg gratings （FBGs）, long-period gratings （LPGs） and tilted fiber gratings （TFGs） into mid-IR 2μm range using three common optical fiber grating fabrication techniques （two-beam holographic, phase mask and point-by-point）. The fabricated FBGs have been evaluated for thermal and strain response. It has been revealed that the FBG devices with responses in mid-IR range are much more sensitive to temperature than that in near-IR range. To explore the unique cladding mode coupling function, we have investigated the thermal and refractive index sensitivities of LPGs and identified that the coupled cladding modes in mid-IR range are also much more sensitive to temperature and surrounding medium refractive index change. The 45° tilted fiber gratings （45°-TFGs） as polarizing devices in mid-IR have been investigated for their polarization extinction characteristics. As efficient reflection filters and in-cavity polarizers, the mid-IR FBGs and 45°-TFGs have been employed in fiber laser cavity to realize multi-wavelength 2μm Tm-doped CW and mode locked fiber lasers, respectively.展开更多
We demonstrate a mid-IR ZnGeP2 （ZGP） optical parametric oscillator （OPO） pumped by a dual-end-pumped actively aeoasto-optie Q-switched Ho：YAG ceramic laser. The maximum average output power of 35 W is obtained at...We demonstrate a mid-IR ZnGeP2 （ZGP） optical parametric oscillator （OPO） pumped by a dual-end-pumped actively aeoasto-optie Q-switched Ho：YAG ceramic laser. The maximum average output power of 35 W is obtained at a pulse repetition frequency of 20 kHz from the Ho：YAG ceramic laser. Under the maximum incident pump power of Ho：YAG ceramic laser, the maximum output power of 14 W is obtained from the ZGP OPO, corresponding to the slope efficiency of 49.6% with respect to the incident pump power. The wavelength can be tuned from 3.5 μm to 4.2μm （signal）, corresponding to 5.24.1 μm （idler）. The beam quality M2 is less than 2.3 from the ZGP OPO.展开更多
A novel widely tunable dual-wavelength mid-IR difference frequency generation （DFG） scheme with uniform grating periodically poled lithium niobate （PPLN） is presented in this paper. By using the temperature-depend...A novel widely tunable dual-wavelength mid-IR difference frequency generation （DFG） scheme with uniform grating periodically poled lithium niobate （PPLN） is presented in this paper. By using the temperature-dependent dispersion property of PPLN, the quasi-phase matching （QPM） peak for the pump may evolve into two separate ones and the wavelength spacing between them increases with the decrease of the crystal temperature. Such two pump QPM peaks may allow simultaneous dual-wavelength mid-IR laser radiations while properly setting the two fundamental pump wavelengths. With this scheme, mid-IR dual-wavelength laser radiations at around 3.228 and 3.548, 3.114 and 3.661, and 3.019 and 3.76 μm, are experimentally achieved for the crystal temperatures of 90, 65, and 30 ℃, respectively, based on the fiber laser fundamental lights.展开更多
Metalens are planar lenses composed of the subwavelengthh arrays,which have unconventional and versatile functionalities to manipulate the light fields compared with the traditional lens.It is noted that the most meta...Metalens are planar lenses composed of the subwavelengthh arrays,which have unconventional and versatile functionalities to manipulate the light fields compared with the traditional lens.It is noted that the most metalens are designed in a monochromatic mode in the visible or mid-infrared range(mid-IR),however,the broadband range is needed in many practical applications,such as spectroscopy,sensing,and imaging.Here,we design and demonstrate a broadband achromatic dielectric metalens in the mid-IR range of 4μm-5μm for near diffraction-limited(1.0a)focusing.The broadband achromatic propagation and focusing of the metalens are designed and simulated by constructing and optimizing the phase profile.The Pancharatnam-Berry(P-B)phases of all the elements contribute to the main phase increment of the whole phase profile of the metalens.The additional phase is constructed and optimized by using the random search algorithm to obtain the optimized size of all the elements.The focusing efficiency of the achromatic metalens is also optimized and averaged as the result of phase optimization within a wide band for the building elements,while it is lowered comparing with the regular metalens without broadband achromatic designing.Using this combined designing approach,various flat achromatic devices with the broadband metalens can find a new way for full-color detection and imaging.展开更多
Mid-infrared （mid-IR） （2-20 μm） photonics has numerous chemical and biologic ＂fingerprint＂ sensing applications due to characteristic vibrational transitions of molecules in the mid-IR spectral region. Unfortun...Mid-infrared （mid-IR） （2-20 μm） photonics has numerous chemical and biologic ＂fingerprint＂ sensing applications due to characteristic vibrational transitions of molecules in the mid-IR spectral region. Unfortunately, compared to visible light and telecommunication band wavelengths, photonic devices and applications have been difficult to develop at mid-IR wavelengths because of the intrinsic limitation of conventional materials. Breaking a new ground in the mid-IR science and technology calls for revolutionary materials. Graphene, a single atom layer of carbon arranged in a honey-comb lattice, has various promising optical and electrical properties because of its linear dispersion band structure and zero band gap features. In this review article, we discuss recent research develop- ments on mid-IR graphene photonics, in particular ultrafast lasers and photodetectors. Graphene-photonics-based biochemical applications, such as plasmonic sensing, photo- dynamic therapy, and florescence imaging are also reviewed.展开更多
Nonlinear optical(NLO)crystals have been playing an increasingly important role in laser science and technology.The NLO crystals used in the middle infrared(mid-IR)region,compared with the NLO crystals in the other wa...Nonlinear optical(NLO)crystals have been playing an increasingly important role in laser science and technology.The NLO crystals used in the middle infrared(mid-IR)region,compared with the NLO crystals in the other wavelength regions,are still not good enough for the application of high-energy laser.The main defect is that their laser damage thresholds(LDT)are low.Chinese scientists have made a lot of important contributions to the UV and visible NLO crystals.In the last decade,they also did a lot of work on the mid-IR NLO materials.The main purpose of these researches is to increase the LDT and simultaneously balance the other properties.This paper presents a brief summary of their research progress in this topic on three types of materials:chalcogenides,oxides,and halides.The emphasis is put on the design strategy and quality control of the crystals.展开更多
In the present paper,FT-mid-IR fiber optics spectroscopy was used to determine the thyroid tumor.A modified WQF-500 FTIR spectrometer with MCT detector and mid-IR fiber optics ATR accessory was used in this work.Percu...In the present paper,FT-mid-IR fiber optics spectroscopy was used to determine the thyroid tumor.A modified WQF-500 FTIR spectrometer with MCT detector and mid-IR fiber optics ATR accessory was used in this work.Percutaneous examination of the skin overlying the thyroid tumor was performed on five patients,in vivo detection and in vitro measurement of six patients in operation room was also carried out.The experimental data indicate that malignant and benign thyroid tumor could be distinguished from the spectra of percutaneous examination,the in vivo measurement and freshly resected thyroid tissues.The relative intensity and peak position of the IR bands in the region of 1 700-1 500 cm-1（amide Ⅰ and amide Ⅱ）,1 480-1 400 cm-1,and 1 320-1 200 cm-1 are reliable spectral marker or indexes for tumor detection.These results demonstrate that FT-mid-IR fiber optics spectroscopy exhibits prospect to develop a novel non-invasive method for thyroid tumor detection.展开更多
The non-invasive detection of breast tumor in vivo and in situ was first investigated by FTIR fiber optics technique. The experiment result indicates that there are significant differences between the spectra of skin ...The non-invasive detection of breast tumor in vivo and in situ was first investigated by FTIR fiber optics technique. The experiment result indicates that there are significant differences between the spectra of skin outside breast tumor and normal breast tissues in the peak position and relative intensity. The in vivo FTIR spectroscopy can provide the information concerning whether the suspected tissue is cancerous or not. This recent result means that in situ FTIR spectroscopic method with fiber optics can be developed as a non-invasive, rapid and in vivo technique for early breast tumor detection.展开更多
Our previous studies show that mid-FTIR spectroscopy can be used to distinguish malignant oral tissue from normal tissue under in vitro condition. Here, an in-situ FTIR spectroscopic measurement was performed to recor...Our previous studies show that mid-FTIR spectroscopy can be used to distinguish malignant oral tissue from normal tissue under in vitro condition. Here, an in-situ FTIR spectroscopic measurement was performed to record FTIR spectra of normal and malignant oral tissues including salivary gland, tongue, parotid gland, submandibular gland etc. during clinical examination. The FTIR spectra of various oral tissues were acquired when an ATR probe linked to the FTIR spectrometer via mid-IR optical fibers was pressed on the tissues of the patients. For example, a patient(male, 76 years old) with tumor on the left parotid and the corresponding normal tissue on the right parotid were measured and obvious differences were observed. The spectral features of normal tissue and tumor are in good agreement with the criteria established in our previous work. (1) 1 389 cm -1 band is quite strong in tumor, while the corresponding band in normal tissue is weaker than 1 452 cm -1 band. (2) In normal tissue, 1 250 cm -1 band is stronger, but the 1 250 cm -1 band disappeared in the skin of malignant tissue. The above results demonstrate that in vivo FTIR spectra are in good agreement with our previous results obtained under in vitro condition. We believe that in vivo FTIR spectroscopy, providing the first-hand information concerning whether the suspected tissue is cancerous or not, is helpful for doctors in clinical activity.展开更多
基金We are grateful for financial supports from National Key Research and Development Program of China(No.2019YFB2203402)National Natural Science Foundation of China(Nos.11774383,11774099,11874029)+3 种基金Guangdong Science and Technology Program International Cooperation Program(2018A050506039)Guangdong Natural Science Founds for Distinguished Young Scholars(No.2020B151502074),Pearl River Talent Plan Program of Guangdong(No.2019QN01X120)Fundamental Research Funds for the Central Universities,Royal Society Newton Advanced Fellowship(No.NA140301)Key Frontier Scientific Research Program of the Chinese Academy of Sciences(No.QYZDBSSW-JSC014).
文摘Gas identification and concentration measurements are important for both understanding and monitoring a variety of phenomena from industrial processes to environmental change.Here a novel mid-IR plasmonic gas sensor with on-chip direct readout is proposed based on unity integration of narrowband spectral response,localized field enhancement and thermal detection.A systematic investigation consisting of both optical and thermal simulations for gas sensing is presented for the first time in three sensing modes including refractive index sensing,absorption sensing and spectroscopy,respectively.It is found that a detection limit less than 100 ppm for CO2 could be realized by a combination of surface plasmon resonance enhancement and metal-organic framework gas enrichment with an enhancement factor over 8000 in an ultracompact optical interaction length of only several microns.Moreover,on-chip spectroscopy is demonstrated with the compressive sensing algorithm via a narrowband plasmonic sensor array.An array of 80 such sensors with an average resonance linewidth of 10 nm reconstructs the CO2 molecular absorption spectrum with the estimated resolution of approximately 0.01 nm far beyond the state-of-the-art spectrometer.The novel device design and analytical method are expected to provide a promising technique for extensive applications of distributed or portable mid-IR gas sensor.
文摘We have UV-inscribed fiber Bragg gratings （FBGs）, long-period gratings （LPGs） and tilted fiber gratings （TFGs） into mid-IR 2μm range using three common optical fiber grating fabrication techniques （two-beam holographic, phase mask and point-by-point）. The fabricated FBGs have been evaluated for thermal and strain response. It has been revealed that the FBG devices with responses in mid-IR range are much more sensitive to temperature than that in near-IR range. To explore the unique cladding mode coupling function, we have investigated the thermal and refractive index sensitivities of LPGs and identified that the coupled cladding modes in mid-IR range are also much more sensitive to temperature and surrounding medium refractive index change. The 45° tilted fiber gratings （45°-TFGs） as polarizing devices in mid-IR have been investigated for their polarization extinction characteristics. As efficient reflection filters and in-cavity polarizers, the mid-IR FBGs and 45°-TFGs have been employed in fiber laser cavity to realize multi-wavelength 2μm Tm-doped CW and mode locked fiber lasers, respectively.
基金Supported by the National Natural Science Foundation of China under Grant Nos 61308009,61405047 and 50990301the Fundamental Research Funds for the Central Universities under Grant Nos HIT.NSRIF.2014044 and HIT.NSRIF.2015042the Science Fund for Outstanding Youths of Heilongjiang Province under Grant No JQ201310
文摘We demonstrate a mid-IR ZnGeP2 （ZGP） optical parametric oscillator （OPO） pumped by a dual-end-pumped actively aeoasto-optie Q-switched Ho：YAG ceramic laser. The maximum average output power of 35 W is obtained at a pulse repetition frequency of 20 kHz from the Ho：YAG ceramic laser. Under the maximum incident pump power of Ho：YAG ceramic laser, the maximum output power of 14 W is obtained from the ZGP OPO, corresponding to the slope efficiency of 49.6% with respect to the incident pump power. The wavelength can be tuned from 3.5 μm to 4.2μm （signal）, corresponding to 5.24.1 μm （idler）. The beam quality M2 is less than 2.3 from the ZGP OPO.
基金Project supported by the National Natural Science Foundation of China(Grant No.11374161)the Open Research Project of Jiangsu Provincial Key Labo-ratory of Meteorological Observation and Information Processing,China(Grant No.KDXS1206)the Project Funded by the Priority Academic Program Development of Jiangsu Provincial Higher Education Institutions,China
文摘A novel widely tunable dual-wavelength mid-IR difference frequency generation （DFG） scheme with uniform grating periodically poled lithium niobate （PPLN） is presented in this paper. By using the temperature-dependent dispersion property of PPLN, the quasi-phase matching （QPM） peak for the pump may evolve into two separate ones and the wavelength spacing between them increases with the decrease of the crystal temperature. Such two pump QPM peaks may allow simultaneous dual-wavelength mid-IR laser radiations while properly setting the two fundamental pump wavelengths. With this scheme, mid-IR dual-wavelength laser radiations at around 3.228 and 3.548, 3.114 and 3.661, and 3.019 and 3.76 μm, are experimentally achieved for the crystal temperatures of 90, 65, and 30 ℃, respectively, based on the fiber laser fundamental lights.
基金supported by the Key Research&Development Project of Sichuan Provincial Department of Science and Technology(Grant No.2021YFG0369)State Grid Science and Technology Project(Grant No.55700-202127198A-0-0-00).
文摘Metalens are planar lenses composed of the subwavelengthh arrays,which have unconventional and versatile functionalities to manipulate the light fields compared with the traditional lens.It is noted that the most metalens are designed in a monochromatic mode in the visible or mid-infrared range(mid-IR),however,the broadband range is needed in many practical applications,such as spectroscopy,sensing,and imaging.Here,we design and demonstrate a broadband achromatic dielectric metalens in the mid-IR range of 4μm-5μm for near diffraction-limited(1.0a)focusing.The broadband achromatic propagation and focusing of the metalens are designed and simulated by constructing and optimizing the phase profile.The Pancharatnam-Berry(P-B)phases of all the elements contribute to the main phase increment of the whole phase profile of the metalens.The additional phase is constructed and optimized by using the random search algorithm to obtain the optimized size of all the elements.The focusing efficiency of the achromatic metalens is also optimized and averaged as the result of phase optimization within a wide band for the building elements,while it is lowered comparing with the regular metalens without broadband achromatic designing.Using this combined designing approach,various flat achromatic devices with the broadband metalens can find a new way for full-color detection and imaging.
文摘Mid-infrared （mid-IR） （2-20 μm） photonics has numerous chemical and biologic ＂fingerprint＂ sensing applications due to characteristic vibrational transitions of molecules in the mid-IR spectral region. Unfortunately, compared to visible light and telecommunication band wavelengths, photonic devices and applications have been difficult to develop at mid-IR wavelengths because of the intrinsic limitation of conventional materials. Breaking a new ground in the mid-IR science and technology calls for revolutionary materials. Graphene, a single atom layer of carbon arranged in a honey-comb lattice, has various promising optical and electrical properties because of its linear dispersion band structure and zero band gap features. In this review article, we discuss recent research develop- ments on mid-IR graphene photonics, in particular ultrafast lasers and photodetectors. Graphene-photonics-based biochemical applications, such as plasmonic sensing, photo- dynamic therapy, and florescence imaging are also reviewed.
基金This work was supported by the National Basic Research Project of China(No.2010CB630701)the National Natural Science Foundation of China(No.91022036).
文摘Nonlinear optical(NLO)crystals have been playing an increasingly important role in laser science and technology.The NLO crystals used in the middle infrared(mid-IR)region,compared with the NLO crystals in the other wavelength regions,are still not good enough for the application of high-energy laser.The main defect is that their laser damage thresholds(LDT)are low.Chinese scientists have made a lot of important contributions to the UV and visible NLO crystals.In the last decade,they also did a lot of work on the mid-IR NLO materials.The main purpose of these researches is to increase the LDT and simultaneously balance the other properties.This paper presents a brief summary of their research progress in this topic on three types of materials:chalcogenides,oxides,and halides.The emphasis is put on the design strategy and quality control of the crystals.
文摘In the present paper,FT-mid-IR fiber optics spectroscopy was used to determine the thyroid tumor.A modified WQF-500 FTIR spectrometer with MCT detector and mid-IR fiber optics ATR accessory was used in this work.Percutaneous examination of the skin overlying the thyroid tumor was performed on five patients,in vivo detection and in vitro measurement of six patients in operation room was also carried out.The experimental data indicate that malignant and benign thyroid tumor could be distinguished from the spectra of percutaneous examination,the in vivo measurement and freshly resected thyroid tissues.The relative intensity and peak position of the IR bands in the region of 1 700-1 500 cm-1（amide Ⅰ and amide Ⅱ）,1 480-1 400 cm-1,and 1 320-1 200 cm-1 are reliable spectral marker or indexes for tumor detection.These results demonstrate that FT-mid-IR fiber optics spectroscopy exhibits prospect to develop a novel non-invasive method for thyroid tumor detection.
文摘The non-invasive detection of breast tumor in vivo and in situ was first investigated by FTIR fiber optics technique. The experiment result indicates that there are significant differences between the spectra of skin outside breast tumor and normal breast tissues in the peak position and relative intensity. The in vivo FTIR spectroscopy can provide the information concerning whether the suspected tissue is cancerous or not. This recent result means that in situ FTIR spectroscopic method with fiber optics can be developed as a non-invasive, rapid and in vivo technique for early breast tumor detection.
文摘Our previous studies show that mid-FTIR spectroscopy can be used to distinguish malignant oral tissue from normal tissue under in vitro condition. Here, an in-situ FTIR spectroscopic measurement was performed to record FTIR spectra of normal and malignant oral tissues including salivary gland, tongue, parotid gland, submandibular gland etc. during clinical examination. The FTIR spectra of various oral tissues were acquired when an ATR probe linked to the FTIR spectrometer via mid-IR optical fibers was pressed on the tissues of the patients. For example, a patient(male, 76 years old) with tumor on the left parotid and the corresponding normal tissue on the right parotid were measured and obvious differences were observed. The spectral features of normal tissue and tumor are in good agreement with the criteria established in our previous work. (1) 1 389 cm -1 band is quite strong in tumor, while the corresponding band in normal tissue is weaker than 1 452 cm -1 band. (2) In normal tissue, 1 250 cm -1 band is stronger, but the 1 250 cm -1 band disappeared in the skin of malignant tissue. The above results demonstrate that in vivo FTIR spectra are in good agreement with our previous results obtained under in vitro condition. We believe that in vivo FTIR spectroscopy, providing the first-hand information concerning whether the suspected tissue is cancerous or not, is helpful for doctors in clinical activity.
