Traditional tools in temperature measurement such as thermocouples, thermistors, and platinum resistance thermometers are intensity modulated. It is well known that optical frequency has an enormous information capacity and accuracy that would be impossible to duplicate with intensity signals. The objective of this project is to develop an optical frequency-modulated whispering-gallery-mode (WGM) based on-chip dynamic ultrafine temperature measurement system that will enable high-temperature superconductor (HTS) on-chip dynamic thermal management and power applications.
Although optical WGMs in dielectric resonators have great potentials in molecular level and nanoscale detection and measurement technologies, many applications with WGMs suffer from thermal fluctuations due to the thermo-optic and thermal expansion effects. Nevertheless, the thermal effects can be transferred into precise temperature measurement and thermal characterization. This project proposes on-chip dynamic temperature monitoring, in which the sensor head is directly coated to the superconductor wire to form a thin ring and the contact temperature is measured through the WGM resonance frequency shift. The system will determine the critical temperature (< 100 K) in HTS with unprecedented fine resolution and accuracy. A coating study of dielectric materials on superconductor wires will be conducted to enable the fabrication of practical on-chip WGM annular micro-resonators. The project will focus on an extensive evaluation of the coated sensors including electrical, optical, and thermal aspects. A heat transfer analysis will enhance understanding thermal transport in HTS and the proposed sensors for many thermal management and power applications.
Intellectual Merit: This project will improve understanding the fundamentals of photo-electro-thermal effects of materials and the temperature dependence of superconductivity at the micro/nanoscale. It pushes cryogenic temperature measurement resolution to an unprecedented level, providing a new capability for high-end scientific, industrial, space and military systems. Other features of the proposed microsensor include high stability, fast response, and microelectronics compatibility. Superconductor electronics has been experiencing rapid development and the power applications of HTS rely on efficient on-chip dynamic thermal management. The proposed system will measure the actual superconducting wire temperature without interference; and thus, precisely determine the critical temperature. Any tiny temperature improvement in cryogenics and superconductivity could be a milestone. The investigators and their team have successfully conducted some initial studies. They are well-equipped and well-positioned to conduct the proposed research and to fulfill the education goals.
Broader Impacts: Successful development of the microsensor system updates necessary tools for precise measurement and scientific discovery. Compatibility with microelectronics will lead to integrated sensors for on-chip temperature monitoring which is still a challenging task. The project could potentially provide a powerful tool to study the HTS wire stability and be beneficial to the HTS wire and devices development and power applications in cables, motors, and transformers. The results obtained will be disseminated to the relevant research and engineering communities through publications, conference presentations and seminars. They may foster a commercial interest in applications to meet the demand for miniaturization, integration, low temperature, and high accuracy detection. The research and education will be quite useful for training graduate students and gaining meaningful research experience for undergraduates, in particular underrepresented minorities. It offers students the opportunities to expand their intellectual horizon to a bridge connecting the state-of-the-art engineering technologies and basic science. The curriculum and instructional labs at Rutgers will be improved. The international research and education collaboration will be enhanced.
