Study Of One-dimensional Subwavelength Structures For Infrared Transmission/Emission Manipulating

One-dimensional subwavelength structures infrared for transmission/emission manipulating can tune transmission/emission freely according to application requirements which has wide application prospects in the field of building energy saving and sensors.In this thesis,one-dimensional subwavelength structures of VO₂for infrared transmission manipulating and narrowband infrared emitter for infrared emission manipulating are studied.Firstly,a new method for ultra thin film thikness determination is proposed.Then we study on preparation and performance of VO₂ for transmission manipulating and narrowband infrared emitter for emission manipulating.The main findings are summarized as follows:1.Interference fitting method is proposed to characterize the thickness of nanometer ultrathin films.The influence of spectral noise of 1000:1 on the thickness of ultra-thin film determination is simulated theoretically.The determination limit of the interference fitting method can reach 1.0 nm in theory.Experimentally,the thickness of SiO₂ film was used to examine the interference fitting method.The interference fitting method can accurately determine 3.5 nm SiO₂ film,limited by the determination limit of reference method.A double-interference fitting method is proposed by introducing two independent spectra about the refractive index n and the thickness d.Make full use of the spectrum peaks information to reduce the spectral characterization system requirements.In the case of using a low-cost and low-precision fiber optic spectrometer,high-precision measurements can still be made by double-interference fitting method with a determination limit of 3.5 nm.2.A large area of vacuum annealing and real-time determination system,semi-automatic spectrum characterization system and two-dimensional graphics coating aided implement for preparation and determination of one-dimensional subwavelength structure were built successfully.Preparation of VO₂ thin films by room-temperature magnetron sputtering was studied.The effects of annealing parameters and the thickness of vanadium film on the infrared transmission change of VO₂ thin films were studied systematically.It was found that the thickness of vanadium was one of the crucial parameters in the annealing process.The annealing process is dominant by reaction control.A method of tuning the phase transition temperature of VO₂ thin film by controlling oxygen flow was proposed.The phase transition temperature of VO₂ thin film on the amorphous glass substrate can be tuned to 44.7?and the phase transition temperature of vanadium oxide film on crystal sapphire substrate can be tuned to 40.4?.This tuning effect comes from the introduction of V³⁺ions during anoxic annealing,and the V³⁺ions interrupting the V⁴⁺chain,which reducing the phase transition temperature.The preparation method of VO₂ thin film that phase transition temperature near room temperature by room-temperature magnetron sputtering has wide application prospect in intelligent energy-saving glass.In addition,the dual-target co-sputtering method was used to flexibly tune the phase transition temperature of tungsten-doped VO₂ thin films.In this way,the doping ratio can be controlled accurately,and the phase transition temperature of VO₂ thin film can be tuned flexibly.3.High-performance intelligent energy-saving film was prepared.The high temperature and low temperature spectra of VO₂ thin films were fitted by Drude model and Cauchy dispersion model,respectively.And the optical constants of high temperature and low temperature phases of VO₂ thin films were extracted.The effect of tungsten-doped VO₂ film thickness and antireflective film thickness on the performance of the film was simulated.The optimum film thickness was 70 nm for tungsten-doped VO₂ and 50 nm for SiO₂.According to the theoretical design results,a large area sample of 200 mm×200 mm was prepared.The infrared transmission change of the film is 40.4%,the peak transmittance is 46.3%,the infrared transmittance of the high temperature metal phase?100??is as low as 10.6%at the wavelength of 2400 nm and the phase transition temperature is 38.2?,which is suitable for intelligent energy-saving glass.4.Metal-distributed bragg reflector coupled narrowband infrared emitter was proposed and fabricated.The effects of coupling layer and DBR structure on the performance of narrowband infrared emitter are simulated.This kind of emitter was fabricated and its absorption and radiation characteristics were measured and analyzed.The emissivity of metal-distributed bragg reflector coupled narrowband infrared emitter can reach 92%,and Q-factor can reach 117,which was better than the international reported level.At the same time,a back-emitting narrowband infrared emitter is proposed,which can not only achieve higher infrared narrow-band emission,but also eliminate the secondary peak by increasing a long-wave pass film.It is an ideal narrowband infrared emitter.