Fiber optic spectrometers transmit optical signals through optical fibers and perform spectral detection, which are widely used in scientific research and industrial fields. Fiber optic spectrometer is an instrument based on the principle of optical dispersion, which conducts optical signals through optical fibers to achieve rapid and high-precision analysis of parameters such as wavelength and intensity of light. It has been widely used in scientific research, industry, environmental protection, medical and other fields due to its advantages of small size, fast response speed, and high flexibility (remote measurement), gradually replacing some traditional large-scale spectral analysis equipment.
The working principle of fiber optic spectrometer is based on the dispersion and photoelectric conversion of light. The core process is as follows:
Light signal acquisition: A light source (such as a white light source, laser, or LED) generates a light signal and illuminates the sample to be tested. After the sample absorbs, reflects, or transmits the optical signal, the light carrying the sample information enters the optical fiber.
Optical signal transmission: Optical fibers transmit optical signals to the inside of the spectrometer, maintaining signal integrity and reducing optical interference.
Optical signal decomposition: The optical signal enters the collimating objective through the incident slit, becomes quasi parallel light, and is irradiated onto the grating. Grating utilizes the principle of diffraction to disperse light of different wavelengths, forming a spectrum.
Optical signal focusing: The imaging mirror focuses the dispersed spectrum onto the receiving surface of the array detector (such as CCD), forming a spectral plane.
Optoelectronic conversion and data processing: The detector converts the optical signal into an electrical signal, which is then subjected to analog-to-digital conversion (A/D) and amplification. The data processing system analyzes and presents spectral information, such as wavelength and intensity distribution.
Precautions for use
Fiber optic and probe maintenance: Fiber optic end faces are prone to dust and oil contamination, which can cause attenuation of optical signals. Regular wiping with anhydrous ethanol is necessary (using specialized lens paper to avoid scratching); The probe should avoid collisions and high temperatures (especially plastic probes, which can age over time due to high temperatures).
Environmental interference control: During measurement, it is necessary to avoid direct exposure to strong light (such as sunlight, strong lighting), especially for visible spectrum analysis, as external stray light can affect signal accuracy; When measuring with high precision, it is necessary to control the ambient temperature (temperature fluctuations can cause changes in the performance of gratings and detectors, and it is recommended to use them in a stable environment of 20-25 ℃).
Calibration and verification: Regularly calibrate with standard samples (such as mercury lamps and deuterium lamps for wavelength calibration, and standard whiteboards for intensity calibration) to ensure the accuracy of measurement data; After long-term disuse, the first start-up should be preheated for more than 30 minutes, and the measurement should be carried out after the instrument is stable.
Sample pretreatment: Process the sample according to the measurement type (reflection, transmission, fluorescence). For transmission measurement, ensure that the sample is uniform, bubble free (liquid), or scratch free (solid film); Reflection measurement needs to ensure that the sample surface is flat and avoid diffuse reflection interference.