Journals >Laser & Optoelectronics Progress
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2010
Volume: 47 Issue 4
22 Article(s)
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Atmospheric Optics and Oceanic Optics
Atmospheric Correction of CBERS-02′s CCD Image
Chen Hao, Li Jian, and Ma Jinji
A group of reference calibration coefficients for China-Brazil earth resource satellite(CBERS)-02′s CCD data were attained by cross calibration method using LANDSAT-5′s TM data. A method based on meteorological information and ATCOR3 was used in the atmospheric correction of CBERS-02′s CCD four bands. The definition ofA group of reference calibration coefficients for China-Brazil earth resource satellite(CBERS)-02′s CCD data were attained by cross calibration method using LANDSAT-5′s TM data. A method based on meteorological information and ATCOR3 was used in the atmospheric correction of CBERS-02′s CCD four bands. The definition of image and normalized difference vegetation index (NDVI) before correction were compared with them after correction. The result shows that after atmospheric correction the image contrast is enhanced,the mean of NDVI is obviously improved and the difference of NDVI between vegetation and nonvegetation is increased. When the underlying surface is rugged terrain,the corner angle of mountain is distinct,the profile is clear and the original shape is recovered,which benefits the extract of remote sensing information..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 47, Issue 4, 40101 (2010)
Fiber Optics and Optical Communications
Ultraviolet Communication System Based on Deep LED
Zhao Ming, Xiao Shali, Wang Xi, Shi Jun, Huang Rui, and Jiang Rongrong
Considering the shortcomings of low data rate,low response speed,high driving voltage,low electrical to optical efficiency and excessive power of the existing short range ultraviolet (UV) communication system based on low pressure mercury lamps,an improved short-range UV communication system based on deep UV LED is proConsidering the shortcomings of low data rate,low response speed,high driving voltage,low electrical to optical efficiency and excessive power of the existing short range ultraviolet (UV) communication system based on low pressure mercury lamps,an improved short-range UV communication system based on deep UV LED is proposed. This system takes pulse position modulation (PPM) and adaptive maximum likelihood demodulation as the key technologies. Photomultiplier tube is used to detect the weak optical signal. The scheme is simulated and realized by field programmable gate array. The simulation and experiment results indicate that the data rate and electrical to optical efficiency of the proposed system are improved greatly,and system power and driving voltage are also decreased..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 47, Issue 4, 40602 (2010)
Error Analysis of Fiber Time Service Using Round-Trip Method
Ding Xiaoyu, Lu Lin, Zhang Baofu, and Dai Yufeng
The emergence of optical clock and the precision limits of the existing time synchronization space-based make fiber one of the major high-precision time service systems. A Round-Trip method that uses dense wavelength division multiplexing (DWDM) technology in a single fiber and achieves bidirectional time information tThe emergence of optical clock and the precision limits of the existing time synchronization space-based make fiber one of the major high-precision time service systems. A Round-Trip method that uses dense wavelength division multiplexing (DWDM) technology in a single fiber and achieves bidirectional time information transfer is introduced. This method restrains the delay time asymmetry of the optical time service using fiber business channel. The time deviation and random error are analysed by using typical parameters of various modules and the character of the fiber channel in the system,and the corresponding suppression of deviation and compensation of random error methods are brought forward. Theoretical analysis shows that the method can satisfy time-precision of nanosecond order of magnitude in the existing fiber distance relay. Taking advantage of the time interval,the delay time and the time stability of the major modules in the 50 km fiber time service system are measured,verifying the theoretical analysis..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 47, Issue 4, 40603 (2010)
Fourier Optics and Signal Processing
Measurement System of Stokes Parameters by Virtual Instrument
Wang Libo, Shi Zhidong, Yin Jun, and Chen Hua
By the method of rotating quarter-wave plate,an automatic measurement system for the Stokes parameters of polarization state has been set up. It can process and display 15 polarization ellipses per second. The virtual instrument in this system consists of a data acquisition card and the LabVIEW software. The rotating aBy the method of rotating quarter-wave plate,an automatic measurement system for the Stokes parameters of polarization state has been set up. It can process and display 15 polarization ellipses per second. The virtual instrument in this system consists of a data acquisition card and the LabVIEW software. The rotating angle is determined precisely by data interpolation and resample,so that the systematic error caused by the instability of rotating motor is depressed. The variation equation of transmitting light intensity with the rotating angle is deduced theoretically by Mueller matrix. The real-time acquired data is compared and fitted with the analytic equation. The coefficients of the variation equation and the correspondent Stokes parameters are given by Fourier transform. The field components and their phase difference of light wave are calculated. The distinction ratio,long axis orientation and spin-wise of polarization ellipse are determined. The influence of background noise on the measurement result is examined. The performances are compared between the two methods of rotating wave-plate and rotating analyzer..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 47, Issue 4, 40701 (2010)
A Novel De-Noising Algorithm of Fission Neutrons Signals by Photoelectric Detection
Jin Jing, Wei Biao, Feng Peng, Tang Yuelin, Ren Yong, and Mi Deling
The empirical mode decomposition (EMD) is applied to analysis and processing of the fission neutrons events based on photoelectric detection. A new model on the de-noise of fission neutrons signals is established with self-adapting double-smoothness-detecting (DSD) algorithm on intrinsic mode function (IMF),and waveletThe empirical mode decomposition (EMD) is applied to analysis and processing of the fission neutrons events based on photoelectric detection. A new model on the de-noise of fission neutrons signals is established with self-adapting double-smoothness-detecting (DSD) algorithm on intrinsic mode function (IMF),and wavelet threshold filter. With the simulated and survey data,a series of comparisons with other signal de-noise methods are made. On an equal footing,the EMD-based-DSD has a better adaptability on various fission neutrons signals. The signal-to-noise ratio of the treated signal is higher while the waveform is more even. The loss of useful information caused by over-de-noise is avoided. Moreover,the de-noise degree can be customized quantifiably..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 47, Issue 4, 40702 (2010)
Image Processing
Underwater Image Enhancement Algorithm Based on Contourlet Transform and Multi-Scale Retinex
Shi Dan, Li Qingwu, Fan Xinnan, and Huo Guanying
Considering the low contrast,fuzzy edge and strong noise of underwater images,an underwater image enhancement algorithm based on nonsubsampled Contourlet transform (NSCT) and multi-scale retinex is proposed. The underwater image is decomposed by nonsubsampled Contourlet transform. Then multi-scale Retinex (MSR) is usedConsidering the low contrast,fuzzy edge and strong noise of underwater images,an underwater image enhancement algorithm based on nonsubsampled Contourlet transform (NSCT) and multi-scale retinex is proposed. The underwater image is decomposed by nonsubsampled Contourlet transform. Then multi-scale Retinex (MSR) is used to enhance the image’s global contrast in the low frequency subband,and an improved Sigmoid function is used to process the coefficients at each scale in the directional bandpass subbands respectively,which suppresses small coefficients and enhances large coefficients by threshold denoising method. Finally,the enhanced coefficients are reconstructed to obtain enhanced image. Compared with the other traditional methods,the approach reduces the noise of original images,improves the contrast of the image,enhances object’s contour and achieves higher quantitative contrast assessment indicator..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 47, Issue 4, 41001 (2010)
Image Quality Assessment and Some Solving Approaches to Current Issues
Zhao Wenzhe, and Qin Shiyin
According to the current development trends in the image quality assessment,a series of assessment methodologies and their corresponding measures were comparatively analyzed in depth. Several conventional measures of performance indices are tested with samples from the image database of LIVE in U-Texas at Austin,based According to the current development trends in the image quality assessment,a series of assessment methodologies and their corresponding measures were comparatively analyzed in depth. Several conventional measures of performance indices are tested with samples from the image database of LIVE in U-Texas at Austin,based on which the monotonicity,veracity,and consistency of various index measures are discussed,expounded and commented by using the subjective scores in the database,so as to indicate their applicability and limitations. Thus the VQEG standard is employed to validate the correctness of the above results. Moreover,some important issues in engineering applications and possible solving approaches are proposed based on the current development trends and requirements of practical applications..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 47, Issue 4, 41002 (2010)
Instrumentation, Measurement and Metrology
Laser Self-Mixing Interference Vibrometer Based on Current Modulation and DSP Demodulation
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The modulation and demodulation technology of semiconductor laser self-mixing interference vibrometer is researched. With triangular wave modulation and DSP demodulation technology of self-mixing interference,a new type vibrometer is designed to achieve non-contact vibration measurement of a target. The theoretical modThe modulation and demodulation technology of semiconductor laser self-mixing interference vibrometer is researched. With triangular wave modulation and DSP demodulation technology of self-mixing interference,a new type vibrometer is designed to achieve non-contact vibration measurement of a target. The theoretical model of the laser self-mixing interference vibrometer is analyzed and simulation and measurement error analysis are done using matlab. The modulation and demodulation technology of the vibrometer system and DSP-based data acquisition and processing system are researched. The vibrometer is small-sized,low-cost and easy to collimate,and can measure the object whose vibration frequency range arrives 5 kHz,and the vibration scope measuring accuracy may achieve 0.325 μm. The instrument can measure the vibration frequency and amplitude data of the vibration object and restore the vibration wave..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 47, Issue 4, 41201 (2010)
Measurement Errors in 632.8 nm High Precision Phase-Shifting Fizeau Interferometer
Wei Haoming, Xing Tingwen, Li Yun, and Liu Zhixiang
To satisfy the need of nanometer measurement for high accuracy optical system,the design of nanometer measurement 632.8 nm phase-shifting Fizeau interferometer is presented. The elementary configuration and measuring principle of the 632.8 nm phase-shifting Fizeau interferometer to measure concave and convex surface arTo satisfy the need of nanometer measurement for high accuracy optical system,the design of nanometer measurement 632.8 nm phase-shifting Fizeau interferometer is presented. The elementary configuration and measuring principle of the 632.8 nm phase-shifting Fizeau interferometer to measure concave and convex surface are introduced. Some errors that affect the accuracy of interferometer are pointed out,including phase-shifting error,geometrical configuration induced error,vibration error and errors caused by CCD,laser source and fluctuating surroundings. The magnitude of measurement errors is obtained through analysis and simulation,among which phase-shifting error,geometrical configuration induced error,vibration error and fluctuating surroundings have great influence. Finally a group of system parameters and environment paraments for 632.8 nm phase-shifting Fizeau interferometer to realize nanometer measurement are given in theory..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 47, Issue 4, 41202 (2010)
Evaluation and Improve Ment of Beam Quality of Slab Laser
Hu Shijie, and Wu Jian
Several evaluation methods for laser beam quality were reviewed,their applicability for the outline characteristic of slab laser was analyzed and an evaluation method for slab laser was chosen. To get good beam quality of slab laser,a correlative technique can be used to improve beam quality of slab laser while the lasSeveral evaluation methods for laser beam quality were reviewed,their applicability for the outline characteristic of slab laser was analyzed and an evaluation method for slab laser was chosen. To get good beam quality of slab laser,a correlative technique can be used to improve beam quality of slab laser while the laser is designed. When the shape of the rectangle beam of slab laser is changed,the adaptive optics technique can be used to improve beam quality. For output beam of the practical slab laser,good quality beam can be got after adaptive optics is used..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 47, Issue 4, 41203 (2010)
Lasers and Laser Optics
Nanoaperture Vertical-Cavity Surface-Emitting Laser with Metal Nano-Particle
Gao Jianxia, Wang Ling′e, and Song Guofeng
Nano-aperture vertical-cavity surface-emitting lasers (VCSELs) with metal nano-particle are fabricated based on common 850 nm VCSELs. When the diameters of the aperture and the metal nano-particle are 400 nm and 100 nm respectively,the maximum far-field output power reaches 0.5 mW. The fabrication process is introducedNano-aperture vertical-cavity surface-emitting lasers (VCSELs) with metal nano-particle are fabricated based on common 850 nm VCSELs. When the diameters of the aperture and the metal nano-particle are 400 nm and 100 nm respectively,the maximum far-field output power reaches 0.5 mW. The fabrication process is introduced and the output power enhancement due to localized surface plasmon is also analyzed by experiment and theory..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 47, Issue 4, 41401 (2010)
Output Characteristics of Fiber Bragg Grating External Cavity Semiconductor Laser
Li Songbai, Deng Tao, and Wu Jiagui
Based on the ray tracing method,considering the gain distribution with wavelength,the expressions of the output spectrum and output power of the fiber grating external cavity semiconductor lasers (FGECL) are deduced firstly. Combining with carrier rate equation,the fine structure of output spectrum and output power areBased on the ray tracing method,considering the gain distribution with wavelength,the expressions of the output spectrum and output power of the fiber grating external cavity semiconductor lasers (FGECL) are deduced firstly. Combining with carrier rate equation,the fine structure of output spectrum and output power are numerically simulated. The results show that,in the reflective band width of grating the multi-peak structure appears,and the output spectrum becomes firmer with the decrease of the front facet reflectivity. The P-I characteristic of FGECL has been investigated. With the decrease of the front facet reflectivity,the fluctuation of the output power tends minimized and the P-I curve becomes generally a straight line..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 47, Issue 4, 41402 (2010)
Materials
Effect of CdS Concentration on Lifetime of Photoelectrons of (Zn,Cd) S:Cu,Cl Luminescent Materials
Tian Shaohua, Sun Mingsheng, and Li Zhiqiang
The decay process of photoelectrons of (Zn,Cd)S:Cu,Cl luminescence materials after excitation with short pulse laser was investigated by using microwave absorption dielectric spectrum detection technique. It is shown that with the concentration of CdS increasing,the lifetimes of photoelectrons and shallow-trapped electThe decay process of photoelectrons of (Zn,Cd)S:Cu,Cl luminescence materials after excitation with short pulse laser was investigated by using microwave absorption dielectric spectrum detection technique. It is shown that with the concentration of CdS increasing,the lifetimes of photoelectrons and shallow-trapped electrons have a descendent trend. Due to the factor that CdS arouses the descend of the conduction band bottom,it changes the forbidden bandwidth of the luminescent crystal and the combination rate of photoelectrons in conductive band and holes in value band increases,the lifetime of photoelectrons and shallow-trapped electrons is shortened. For the shallow traps shackling,the lifetime of shallow-trapped electrons is longer than that of photoelectrons..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 47, Issue 4, 41601 (2010)
Influence on Spectral Characteristics of Purple Jade by Heat Treatment
Chen Chen, Guo Shouguo, and Mao Jian
Purple jade sample was tested before and after heat treatment under oxidational atmosphere with X-ray diffractometer(XRD),ultraviolet visible (UV-VIS) absorption spectrosmeter and Raman spectrometer. XRD analysis results show that the major components of the sample are jadeite. The sample UV-VIS absorption spectra befoPurple jade sample was tested before and after heat treatment under oxidational atmosphere with X-ray diffractometer(XRD),ultraviolet visible (UV-VIS) absorption spectrosmeter and Raman spectrometer. XRD analysis results show that the major components of the sample are jadeite. The sample UV-VIS absorption spectra before and after heat treatment shows that after heat treatment the spikes at 437 nm and 580 nm almost disappear,while Raman spectra of purple jade brown section after heat treatment shows that the baseline presents rising trend. According to the above analysis,the following conclusion is drawn:the main color-causing ion is Fe2+,while Fe2+ changes to Fe3+after heat treatment and Fe2O3 is formed. Therefore the sample of purple jade shows brown after the heat treatment..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 47, Issue 4, 41602 (2010)
Experimental Study on Polishing Technology of K9 Optical Glass with Fixed Abrasive Pad
Lin Kui, Zhu Yongwei, Li Jun, Li Mao, and Li Suozhu
A new hydrophilic fixed abrasive polishing pad (FAP) was studied. Single factor experiment method was employed to explore the effect of polishing parameters such as polishing time,eccentricity,pressure,rotational speed,flow rate and pH value of slurry with FAP on material removal rate (MRR) and surface roughness of K9 A new hydrophilic fixed abrasive polishing pad (FAP) was studied. Single factor experiment method was employed to explore the effect of polishing parameters such as polishing time,eccentricity,pressure,rotational speed,flow rate and pH value of slurry with FAP on material removal rate (MRR) and surface roughness of K9 optical glass. Results show that MRR drops with time extension. After 20 min polishing,MRR reaches a maximum of 310 nm/min and surface roughness reaches a minimum of 2.73 nm. Large eccentricity distance and alkaline slurry are helpful to improve MRR. With the increase of rotational speed,MRR rises significantly. While in certain range,applied pressure and slurry flow rate have little effect on MRR..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 47, Issue 4, 41603 (2010)
Experimental Research for Binning Technique in Spectroscope
Zhou Wang, Shen Weimin, Zhou Jiankang, and Chen Xinhua
A method combining several pixels into a pixel using Binning technology is proposed,considering that delicacy of linear CCD is lower in spectral analysis. Thereby several performances of linear CCD,such as responsibility,sing-noise ratio and frame speed are enhanced. The researches include discussing the sign output stA method combining several pixels into a pixel using Binning technology is proposed,considering that delicacy of linear CCD is lower in spectral analysis. Thereby several performances of linear CCD,such as responsibility,sing-noise ratio and frame speed are enhanced. The researches include discussing the sign output structure of a CCD,and capturing the spectrum family,and analyzing data of sample. They indicate that combining sensitivity sub-family of spectrum together (Binning) through changing drive sequence of CCD,can get higher sensitivity and signal-noise-ratio (SNR). The influence of Binning on near pixels is discussed..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 47, Issue 4, 41604 (2010)
Medical Optics and Biotechnology
Dual-Wavelength Optical Coherence Tomography System
Ye Qing, Li Fuxin, Liu Yu, Zhou Wenyuan, Zhang Chunping, and Tian Jianguo
An optical coherence tomography (OCT) system with two low coherence sources emitting at 980 nm and 1300 nm is set up. Using this system,we acquire the OCT images of fresh pork at two wavelengths and different source powers respectively. We compare the images obtained at one wavelength with different source power and atAn optical coherence tomography (OCT) system with two low coherence sources emitting at 980 nm and 1300 nm is set up. Using this system,we acquire the OCT images of fresh pork at two wavelengths and different source powers respectively. We compare the images obtained at one wavelength with different source power and at two wavelengths with same source power. The corresponding curves of OCT signals versus detection depth are also discussed. The scattering coefficient change of the tissue with the light emitting at two different wavelengths is analyzed by fitting the curve. Results show that the increase of the source power can finitely improve the probe depth and the increase of the source wavelength can improve the probe depth remarkably. The influence of wavelength on parameters of OCT system and the reason for differences between images are also discussed..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 47, Issue 4, 41701 (2010)
Optical Design and Fabrication
Using Stochastic Parallel Gradient Descent Control Algorithm to Calibrate Sencond Mirror in Three-Mirror System
Han Xingzi, Yu Xin, and Dong Bing
The primary method for calibrating a co-axial three-mirror system is the computer-aided alignment method,and it is complicated for having to calculate wavefront error. Stochastic parallel gradient descent (SPGD) control algorithm is used to caliberate the second mirror of three-mirror system,with no need to calculate wThe primary method for calibrating a co-axial three-mirror system is the computer-aided alignment method,and it is complicated for having to calculate wavefront error. Stochastic parallel gradient descent (SPGD) control algorithm is used to caliberate the second mirror of three-mirror system,with no need to calculate wavefront error. Through adjusting the six degrees of freedom of the second mirror directly,finding system extremal value and then calibrating system error,the calibrating process is predigested. The major factors that will affect computing speed of SPGD algorithm are analysed and optimized,and the simulation results show that SPGD algorithm can distinctly improve peak-valley value and root-mean-square of the system..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 47, Issue 4, 42201 (2010)
Other Areas of Optics
Extraordinary Transmission of TE-Polarization through Periodic Arrays of Metallic Slits Covered with Dielectric Medium
Wang Yawei, Deng Xiaobin, Wang Lifeng, Liu Mingli, and Hang Guangcai
Subwavelength periodic structures have many specific properties different from the traditional structures. Based on these properties,new nano-photonics devices can be designed. Using finite difference time domain (FDTD) numerical simulation methods,abnormal transmission phenomenon under TE polarized light excitation isSubwavelength periodic structures have many specific properties different from the traditional structures. Based on these properties,new nano-photonics devices can be designed. Using finite difference time domain (FDTD) numerical simulation methods,abnormal transmission phenomenon under TE polarized light excitation is realized by adding dielectric coating in the subwavelength peridic metallic slits. By comparing effects of adding dielectric in different locations such as left or right surface of metal films and metallic slits for extraordinary transmission phenomenon,it is proved that dielectric coatings on the metal films can excite a surface wave which transmits in dielectric waveguides in the metal slits,and results in extraordinary transmission phenomenon..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 47, Issue 4, 43101 (2010)
Reviews
Technology and Progress of Compound-Axis Pointing in Satellite Laser Communication
Yan Aimin, Zhou Yu, Sun Jianfeng, and Liu Liren
The satellite laser communications are of potential applications and have reached a level of high data rate,compact and light construction,and low-power consumption in the world. One of the most key technologies is the design and control of pointing,acquisition and tracking (PAT) system. The composite axis system,consiThe satellite laser communications are of potential applications and have reached a level of high data rate,compact and light construction,and low-power consumption in the world. One of the most key technologies is the design and control of pointing,acquisition and tracking (PAT) system. The composite axis system,consisting of the coarse tracking system and the fine tracking system can accomplish the wide ranging and high accuracy tracking tasks. The properties and key technologies of PAT are discussed. And the scanning,acquisition,pointing and tracking processes are introduced. International progress of the compound-axis control system of PAT is reviewed. Finally,the application prospect of compound-axis control system is given..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 47, Issue 4, 40601 (2010)
Applications of Atomic Spectra Filtering and Atomic Frequency Discrimination in Optoelectronic Systems
Gong Shunsheng, Cheng Xuewu, Li Faquan, Yang Guotao, Yang Yong, and Wang Jiamin
Atomic filter is an optoelectronic device used for optical spectra filtering and optical frequency discrimination. As the working frequency of this device is determined by atomic or molecular transitions,the atomic fitler has ultra-high stability of working frequency,ultra-narrow working band-pass,good out-of-band suppAtomic filter is an optoelectronic device used for optical spectra filtering and optical frequency discrimination. As the working frequency of this device is determined by atomic or molecular transitions,the atomic fitler has ultra-high stability of working frequency,ultra-narrow working band-pass,good out-of-band suppression,high transmission,and so on. Therefore,the atomic filters are widely used in the fields of lidar and optical communication,and have enhanced the performance of lidar and optical communication systems. The principle,structure,development and some applications of the atomic filters are introduced and discussed..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 47, Issue 4, 42301 (2010)
Spectroscopy
Detecting Different Teas by Fourier Transform Infrared Spectroscopy
Yang Qun, and Wang Yilin
Unzymic Biluochun tea,zymic Pu-er tea,and half-zymic Oolong tea,were distinguished by Fourier transform infrared spectroscopy. Although they′re similar in infrared spectrum,the results still show differences in the characteristic peaks of infrared spectrum caused by difference between three kinds of teas of different zUnzymic Biluochun tea,zymic Pu-er tea,and half-zymic Oolong tea,were distinguished by Fourier transform infrared spectroscopy. Although they′re similar in infrared spectrum,the results still show differences in the characteristic peaks of infrared spectrum caused by difference between three kinds of teas of different zymic degree.The results show that zymic degrees of teas tie up with variety of absorbance band at about 1037,1147,1324,1520 and 1240 cm . According to the studies of the spectral peaks and absorbance rations,unzymic,half-zymic and zymic teas can be easily identified..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 47, Issue 4, 43001 (2010)
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