Active and accurate temperature control of terahertz functional devices via micro-hotplate system

Based on the problem that the intensity of excitation source is not easy to regulate by the traditional active control method, this paper presents an accurate temperature control system based on micro-hotplate for the first time. This system realizes the active control of terahertz metamaterial functional devices, and implements various functions by using the proposed accurate temperature control process. The temperature control characteristics of micro-hotplate are introduced into the design of terahertz functional devices by taking a vanadium dioxide (VO₂ ) metamaterial absorber as an example. In this design, a silicon-based micro-hotplate is used to heat the metamaterial absorber. According to the phase transition characteristics of VO₂ , the alteration of temperature leads to conductivity change, so as to realize the active control of the absorber. At the same time, this paper also analyzes the heating and cooling time of the micro-hotplate. The simulation results show that, by using the micro-hotplate to heat the metamaterial functional devices, the temperature adjustment speed is reasonably high and the controllable performance is excellent. The test results shows that the surface temperature can be controlled between 40 ℃ and 80 ℃ , and the temperature difference of the working area can be kept within 1℃ . The temperature control of the micro-hotplate is accurately controlled, resulting in the great performance of the metamaterial functional devices.

Q3: A Compact Device for Quick, High Precision qPCR

An accurate and easy-to-use Q3 system for on-chip quantitative real-time Polymerase Chain Reaction (qPCR) is hereby demonstrated, and described in detail. The qPCR reactions take place inside a single-use Lab-on-a-Chip with multiple wells, each with 5 to 15 µL capacity. The same chip hosts a printed metal heater coupled with a calibrated sensor, for rapid and accurate temperature control inside the reaction mixture. The rest of the system is non-disposable and encased in a 7 × 14 × 8.5 (height) cm plastic shell weighing 300 g. Included in the non-disposable part is a fluorescence read-out system featuring up to four channels and a self-contained control and data storage system, interfacing with an external user-friendly software suite. Hereby, we illustrate the engineering details of the Q3 system and benchmark it with seamlessly ported testing protocols, showing that Q3 equals the performance of standard commercial systems. Overall, to the best of our knowledge, this is one of the most mature general-purpose systems for on-chip qPCR currently available.

Device for the detection of short trace gas pulses

A device for detection of short gas pulses at very low concentrations is presented. The approach is based on a special temperature modulation technique enabling a differential surface reduction (DSR) measurement of a metal oxide semiconductor (MOS) gas sensor. With this method, the sensor surface is highly covered with oxidized surface states at high temperature (e. g. 400 °C) initially. The temperature is then reduced abruptly to, e. g., 100 °C resulting in a state with strong excess of negative surface charge. Reactions of these surface charges with reducing gases are prevailing and lead to very high sensitivity. For the measurement a dedicated detector (electronics and fluidic system) is presented. The electronics allows a high-resolution conductance measurement of the sensitive layer and accurate temperature control. The fluidic system is examined in terms of peak shape and optimal sensor response via FEM simulations.