研究目的
To analyze and compare two methods of improving spatial resolution with FTIR spectroscopy in atmospheric-pressure plasma systems: diameter reduction and focusing optics.
研究成果
The focusing optics method improves the SNR compared to the diameter reduction method for sufficiently low plasma background infrared radiation levels. However, the diameter reduction method is less affected by high background plasma infrared radiation and its spatial resolution is limited only by the minimum allowable SNR. The choice between methods depends on the specific requirements of the measurement and the characteristics of the plasma system.
研究不足
The focusing optics method's ability to achieve sub-mm spatial resolution depends on the radiating area of the infrared light source in the spectrometer. The diameter reduction method's spatial resolution is limited by the minimum allowable SNR. Both methods are affected by the background infrared radiation from the plasma.
1：Experimental Design and Method Selection:
The study compares two methods for increasing spatial resolution in FTIR spectroscopy: diameter reduction and focusing optics. The diameter reduction method involves reducing the beam diameter with optical stops, while the focusing optics method uses lenses or mirrors to image the beam onto the sample.
2：Sample Selection and Data Sources:
The experiments were conducted using a nitrogen-filled 50 cm wide vacuum chamber with a plasma sample. Background spectra without plasma were obtained for comparison.
3：List of Experimental Equipment and Materials:
A JASCO FT/IR 6800 spectrometer operating in external beam mode, sapphire ports, MCT detector, iris diaphragms for diameter reduction, and 51.7 cm focal length gold off-axis parabolic mirrors for focusing optics.
4：7 cm focal length gold off-axis parabolic mirrors for focusing optics.
Experimental Procedures and Operational Workflow:
4. Experimental Procedures and Operational Workflow: For diameter reduction, the beam was sent through iris diaphragms to reduce its cross-sectional area. For focusing optics, the beam was imaged onto the sample using parabolic mirrors. The SNR for each method was analyzed and compared.
5：Data Analysis Methods:
The SNR was calculated for each method, taking into account the background infrared radiation from the sample. The spatial resolution achievable with each method was also evaluated.
独家科研数据包，助您复现前沿成果，加速创新突破
获取完整内容
