terahertz आवृत्तियों के लिए एक अंडाकार waveguide समानांतर थाली ज्यामिति के आधार पर एक अपवर्तक सूचकांक संवेदक को लागू करने के लिए प्रक्रिया में वर्णित है यहाँ. विधि waveguide संरचना के गुंजयमान आवृत्ति में बदलाव की निगरानी के माध्यम से तरल पदार्थ की एक छोटी मात्रा के अपवर्तक सूचकांक के एक माप पैदावार
Refractive index (RI) sensing is a powerful noninvasive and label-free sensing technique for the identification, detection and monitoring of microfluidic samples with a wide range of possible sensor designs such as interferometers and resonators 1,2. Most of the existing RI sensing applications focus on biological materials in aqueous solutions in visible and IR frequencies, such as DNA hybridization and genome sequencing. At terahertz frequencies, applications include quality control, monitoring of industrial processes and sensing and detection applications involving nonpolar materials.
Several potential designs for refractive index sensors in the terahertz regime exist, including photonic crystal waveguides 3, asymmetric split-ring resonators 4, and photonic band gap structures integrated into parallel-plate waveguides 5. Many of these designs are based on optical resonators such as rings or cavities. The resonant frequencies of these structures are dependent on the refractive index of the material in or around the resonator. By monitoring the shifts in resonant frequency the refractive index of a sample can be accurately measured and this in turn can be used to identify a material, monitor contamination or dilution, etc.
The sensor design we use here is based on a simple parallel-plate waveguide 6,7. A rectangular groove machined into one face acts as a resonant cavity (Figures 1 and 2). When terahertz radiation is coupled into the waveguide and propagates in the lowest-order transverse-electric (TE1) mode, the result is a single strong resonant feature with a tunable resonant frequency that is dependent on the geometry of the groove 6,8. This groove can be filled with nonpolar liquid microfluidic samples which cause a shift in the observed resonant frequency that depends on the amount of liquid in the groove and its refractive index 9.
Our technique has an advantage over other terahertz techniques in its simplicity, both in fabrication and implementation, since the procedure can be accomplished with standard laboratory equipment without the need for a clean room or any special fabrication or experimental techniques. It can also be easily expanded to multichannel operation by the incorporation of multiple grooves 10. In this video we will describe our complete experimental procedure, from the design of the sensor to the data analysis and determination of the sample refractive index.
यह ध्यान दिया जाना चाहिए कि परीक्षण के अंतर्गत तरल के अपवर्तक सूचकांक एक व्यापक बैंडविड्थ पर गुहा प्रतिध्वनि की आवृत्ति पर ही निर्धारित नहीं है, करना चाहिए. यह कुछ अलग फायदे हैं. सबसे पहले, हालांकि हमा?…
The authors have nothing to disclose.
इस परियोजना के हिस्से में राष्ट्रीय विज्ञान फाउंडेशन द्वारा और संपर्क कार्यक्रम के माध्यम से वायु सेना अनुसंधान प्रयोगशाला द्वारा समर्थित किया गया.
Name of the reagent | Company | Catalogue number | Comments (optional) |
10 μl syringe | Hamilton | 80314 | High precision syringe |
Liquid alkanes | Acros Organics | Samples for calibration and testing | |
No specific equipment is required. Suitable test materials and solvents are left to the experimenter’s discretion. The high-precision syringes used in this procedure are listed in the table below, but the experimenter may wish to use syringes of a different volume or design, including digital syringes for improved accuracy. The test alkanes used in this experiment are also listed. |