Research On Laser Launcher Of Laser-induced Chlorophyll Fluorescence

Plant growth and development are a variety of plant physiological and biochemical changes in the overall performance. Therefore, changes in plant physiological ecology can also reflect the status of plant growth. Effective use of plant physiological and ecological information, the potential ability to exert plant, high efficiency, high quality plant production, so as to promote the effective management of plant cultivation, the growth of disease prevention and control, environmental impact analysis, a better implementation of the on-demand management of crop production .Detect biology of modern agriculture are an important part of scientific research, laser technology for the development of modern agriculture in the detection of Biology provides enormous potential for research tools. Over the last decade, developed by the laser detection biology analytical techniques have laser fluorescence spectroscopy technique, laser microprobe analysis techniques, laser Doppler scattering technology, laser Raman spectroscopy, laser light perturbation techniques, confocal laser scanning technology and so on. Characteristics of the laser is an excellent light source, the radiation beam energy in space, time and frequency are highly concentrated, with good direction, high brightness, good color, good coherence, spectral "purity" high. In analyzing the sample, the sample without pre-treatment, nor destroy the original sample, simple operation, fast analysis speed.Material in the ground state molecules absorb excitation light to the excited state after the transition, the excited state due to molecular rotation, vibration, such as loss of part of excitation energy, the decline in non-radiative transition to a low vibration level, and then dropped from a low vibration level to ground state, in this process, the excited state of the form of light elements will be absorbed by the release of energy, known as fluorescence. Plant's chlorophyll in vivo by laser irradiation will be issued a weak self-fluorescence, and the physiological responses of plants of all kinds of life information was included in the fluorescence spectrum inside.In the fluorescence analysis in order to improve detection sensitivity, the intensity of excitation light demanding, laser with the features:(1) The spectral distribution characteristics of the laser required to stimulate the fluorescence spectrum coverage.(2) Laser on the sample can provide sufficient energy, so that the full sample have a strong excitation and fluorescence radiation, thus enabling measurement with high sensitivity and low detection limit.(3) Laser has good stability and reliability, so that stimulated the process of stability, so that the results of measurement and analysis with good repeatability, fluorescence analysis in order to meet accuracy and precision requirements.(4) Small-angle laser radiation can be coupled with optical fiber coupling and high efficiency.(5) Laser long life, small size, low power consumption.Therefore, the use of laser as the excitation light can greatly enhance the fluorescence intensity, which greatly enhance the sensitivity analysis. Therefore this article in accordance with plant chlorophyll fluorescence excitation fluorescence spectra of conditions designed to meet the plant chlorophyll fluorescence excitation laser launchers.Laser emission laser devices are used in some laser diodes, laser diode is essentially a semiconductor diode, a semiconductor laser belong to. Semiconductor laser work is based on the basic principles of electromagnetic radiation with the semiconductor carrier within the interaction of semiconductors with the electron-photon interaction are also three basic processes - stimulated absorption, spontaneous emission and stimulated emission. When the PN junction semiconductor forward voltage has add, it will weaken the PN junction barrier, forcing the district electron from the N into P by PN junction area, hole area from P into N through PN junction area, near the junction of these into the non-PN balance of electrons and holes will happen compound, which emits a photon wavelength ofλ. Laser diode with low threshold current, high output power advantages. Compared with lasers, laser diodes with high efficiency, small size, the advantages of long life.The main research work and conclusions of the following areas:First of all, this paper, the significance of the subject, the purpose of this article and chlorophyll fluorescence excitation light source selection conditions, in access to relevant documents and materials at home and abroad under the premise of the basic principles of fluorescence generated by semiconductor lasers and the status quo at home and abroad, the basic principles of , characteristics and causes major damage to introduce.Secondly, according to the parameters of laser diodes and the fluorescence excitation test requirements of plants, design a laser diode driver, protection, feedback circuits, and in accordance with the requirements of the entire experimental set of four different parameters of the light-emitting laser diode lines, using single-chip microcomputer to control the selection of a line of switches and display.Finally, the laser emission lines of various real-time measurement, to verify the various circuits throughout the system stability and interoperability, and to accept the chlorophyll fluorescence excited by the perspective of the instrument, such as matching the experimental point of view. Designed and experience necessary to do the work of the future are summarized.