High Resolution Optical Fourier Transform Spectrum Measurement Method Research

Fourier transform spectrum measurement technique in infrared and near infrared band has gradually replaced spectral measurement technology as an important means of optical measurement, high flux, multi-channel, wide measurement range and high spectral calibration accuracy, etc, and in the visible light wave band, it still has high resolution, high measurement precision, high flux, etc.Technology based on the dual beam interference technology and folding, the Fourier transform spectrum measurement technology to optical wavelengths, by improving the optical path, improve the stability of the optical platform system to get high precision of interference pattern, improve the resolution of spectrum measurement system.In this paper, the overall design train of thought:using Michelson interferometer achieve dual intervention, for reference by photometry and light interference figure, two of the moving mirror fixed in the same way interferometer translation stage, have the same amount of moving mirror mobile.Reference light interference figure for photoelectric conversion, signal amplification and the zero comparison, get the positioning signal pulse, by metering interference figure for photoelectric conversion and signal amplification, use of reference light for the positioning of the pulse of the metering signal sampling.Through the data processing system of sampling signal Fourier transform processing, eventually gain spectrum, and achieve the goal of spectrum measurement.Laboratory there are many shortcomings of the original system, the error is bigger, when the system’s resolution cannot achieve the goal of spectrum measurement, which I have done a lot of improvement in the measuring system.Change the reference light source, the original reference light source frequency is not stable, lead to irregular sampling location changes, affect the measurement result, choose the single longitudinal mode stable He-Ne laser light source, to improve the frequency stability;Original system moving mirror mobile device installation platform processing precision rough, uneven mounting holes, and affect the light path in laymen, installed on the platform now add standard optical bread plate, and design the corresponding processing machine such as the installation, improve the system of quasi laymen;By metering part designs the new set of mirror adjustment device, the original system set installed in a large adjustment on the mirror, can’t adjust, we can install in optical bread plate at any position, cause the metering distance beam using the mirror mirror mirror approximately equal, improving metering for multiple frequency phase characteristic of light;The change of optical path difference by translation machine control, change the way the translation table driven, design a new circuit, change the translational ac drive way to dc drive mode, improve the translational vibration impact;Design a new amplifier circuit of photoelectric detection and signal to the reference light signal dc component and the metering ac component respectively.Found in the experiment process shall be limited to the factors of the experimental condition is unable to ensure accuracy of test conditions continue to improve, make the system resolution redesigned by photometric light path, on the light path folding, disguised enables the system to achieve the original system resolution twice, to improve the test performance of the system.This paper on the original experiment system was improved, the experimental results show that the new system greatly reduces the measuring error, improves the resolution of the system.Increasing the optical path of the photometric fold, the experimental results show that the system can measure the spectrum and greatly improve the resolution of the system.Results show that improvement is feasible, this article do system design is perfect and correct.