The optical fiber spectrometer developed by Guangzhou Jingyi Optoelectronics, the world's largest consumer of optical fiber spectrum, uses an asymmetric interspersed optical structure. The design of this optical platform is to stop the improvement of the optical path on the base of the structure, so that the external components of the spectrometer are more compact, and can be installed in a measurement platform small enough to move the palm of the hand. Because the optical path is extended, the parallel array monochromatic light projected by the focusing mirror to the linear CCD array detector is expanded into a circular arc display at a certain Angle, and certain nonlinear errors will occur in the detection of optical signals.
The optical platform design of spectroscopic structure makes the microminiature optical fiber spectrometer without moving components, and the optical components are all reflective, which can increase the aberration to a certain level, and make the task spectral range not affected by the data. The optical piecemeal design of the miniaturized full-fixed parts of the instrument can meet the needs of complex working environment detection such as high vibration and narrow space.
Characteristics of instrument
With the introduction of new optoelectronic devices such as low loss optical fiber, low noise and high sensitivity CCD array detector, holographic grating and small and efficient semiconductor, the functions of micro-miniature spectral instruments have been improved.
(1) The charge coupled device (CCD) array is used as the detector to scan the spectrum without moving the grating, and the transient acquisition can be stopped, and the response speed is very fast (the measurement time is 13 ~ 15ms), and the computer is input in real time.
(2) The introduction of optical fiber technology makes the object to be measured free from the limit of the sample pool, and the sampling method becomes more sensitive. The optical fiber probe is used to lead the sample spectral source far from the spectral instrument to the spectral instrument to comply with the complex shape and status of the sample to be measured. The optical signal introduced by the optical fiber can also isolate the outside of the instrument from the external environment, which can strengthen the resistance to the harsh environment (wet climate, strong electric field disturbance, corrosive gas), ensure the temporary reliable operation of the spectrometer, and extend the service life.
(3) The use of computer technology has greatly improved the intelligent disposal ability of the spectrometer.
The optical fiber spectrometer measurement system also has the characteristics of modularity, which can be selected according to the different needs of the use of components (including a variety of different types of sampling fiber probes, dispersion elements, focusing optical systems and detectors, etc.), and build an optical platform. Although the measurement accuracy of the micro-fiber spectrometer is considered to be lower than that of the traditional off-line photometer designed with moving raster and photocell, it has reached the requirement of spectral analysis in the industrial field.
(4) Using holographic grating as a spectral device, low stray light, improve the measurement accuracy.
Application of microminiature optical fiber spectrometer in process monitoring
With the emergence of micro-optical fiber spectrometers, spectral technology has also experienced a reaction from the laboratory to the consumer scene, and has been transformed into a suitable technology to design field instruments completely centered on the sample under test. In practical consumption, the online measurement fragments of ultraviolet, visible light, near infrared, Raman scattering and fluorescence analysis platforms are presented.
Fluorescence profiling
Fluorescence measurement requires highly sensitive detectors and ineffective filters that can distinguish the absolutely weak fluorescence of the photosynthetic sample that excites the light source. Optical fiber spectrometer can detect the surface fluorescence of solution and powder in the range of 360-1000nm, the use of fluorescence analysis technology can also measure the relative content of oxygen in the sample, can be LED excitation light source and micro-spectrometer with optical fiber fluorescence probe composed of oxygen concentration sensor measurement fragments, according to the quenching level of fluorescence and oxygen concentration related principle to stop real-time monitoring.
Optical fiber spectrometer with modular and sensitivity, compact instrument structure, exquisite, external no moving parts, wavelength cover range (190-2500nm), fast measurement speed (less than 0.1 seconds) and other advantages, suitable for industrial online monitoring, and the spectrometer selection of low cost general purpose detector, greatly reduce the use of the price threshold. In recent years, the development of chemometrics, optical fiber and computer technology has provided a very broad application space for the online monitoring system centered on optical fiber spectrometer.
