Single-photon emission and multi-photon emission from single CdTeSe/ZnS quantum dots at room temperature

In this report, single-photon emission and ordered multi-photon emission from single colloidal CdTeSe/ZnS quantum dots at near-infrared wavelength were realized at room temperature. The fluorescence lifetime, blinking, and anti-bunching effect of this single quantum dots at different excitation powers were measured. The relationship between the excitation power and the emission of exciton, biexciton and multiexciton of single quantum dots at a wavelength of 800nm was obtained. The physical mechanism of photoluminescence of the single quantum dots was analyzed.

A Low Cost Silicon Based Thermal Camera for Volcanic Applications

<p class="western" lang="en-GB" align="justify">Volcanic gases and the chemical reactions inside volcanic emission plumes are of great interest because of their impact on atmospheric processes and climate. The evolution of many volcanic gas compounds is most likely strongly dependent on the general physical conditions during the emission processes. Particularly, the knowledge about the temperature of the lava, i.e. the origin of the gases, is crucial.</p> <p class="western" lang="en-GB" align="justify">Commercially available thermal cameras for the relevant temperature range (ca. 600-1200 °C) are still rather expensive, bulky, and have a limited spatial resolution.</p> <p class="western" lang="en-GB" align="justify">We present an approach to use a compact (‘point and shoot’) consumer digital camera with a silicon based detector as a thermometer to record the spatial temperature distribution and variations of volcanic lava. Silicon detectors are commonly sensitive in the near infrared wavelength range (until ca. 1100 nm), which readily allows measurements of temperatures above ca. 500 °C. The camera is modified to block the visible spectrum and the remaining colour filter (Bayer filter) characteristics are used to infer the temperature from differential intensity measurements.</p> <p class="western" lang="en-GB" align="justify">In the frame of this work, we performed a sensitivity study and calibrated the camera with a heated wire in the range of 600-1100 °C. Besides the advantages of superior mobility and simple handling, the 16 megapixel spatial resolution of the temperature measurement allows resolving detailed temperature distributions in highly dynamic volcanic emission processes.</p>

Исследование поверхностного окисления циркония активным тепловым методом

The possibility of testing the surface oxidation of zirconium has been investigated by the method of one-way active thermal non-destructive testing based on the analysis of radiation temperatures. The emissivity of the oxidized surface of zirconium samples obtained at different annealing temperatures was estimated at various stages and heating temperatures in the infrared wavelength range. It is shown that there is a principal possibility to remotely test the oxidation process of zirconium alloys used in the nuclear industry for the manufacture of fuel elements operating in the core of nuclear reactors.

Infrared antenna-like structures in mammalian fur

Many small animals, including shrews, most rodents and some marsupials, have fur composed of at least four types of hair, all with distinctive and complex anatomy. A ubiquitous and unexplained feature is periodic, internal banding with spacing in the 6–12 µm range that hints at an underlying infrared function. One bristle-like form, called guard hair, has the correct shape and internal periodic patterns to function as an infrared antenna. Optical analysis of guard hair from a wide range of species shows precise tuning to the optimum wavelength for thermal imaging. For heavily predated, nocturnal animals the ability to sense local infrared sources has a clear survival advantage. The tuned antennae, spectral filters and waveguides present in guard hair, all operating at a scale similar to the infrared wavelength, could be a rich source of bio-inspiration in the field of photonics. The tools developed in this work may enable us to understand the other hair types and their evolution.

Integrated NIR-HE based SPOT-5 image enhancement method for features preservation and edge detection

Recently, many researchers have directed their attention to methods of predicting shorelines by the use of multispectral images. Thus, a simple and optimised method using image enhancements is proposed to improve the low contrast of the Satellite pour l'Observation de la Terre-5 (SPOT-5) images in the detection of shorelines. The near-infrared (NIR) channel is important in this study to ensure the contrast of the vegetated area and sea classification, due to the high reflectance of leaves in the near infrared wavelength region. This study used five scenes of interest to show the different results in shoreline detection. The results demonstrated that the proposed method performed in an enhanced manner as compared to current methods when dealing with the low contrast ratio of SPOT-5 images. As a result, by utilising the near-infrared histogram equalization (NIR-HE), the contrast of all datasets was efficiently restored, producing a higher efficiency in edge detection, and achieving higher overall accuracy. The improved filtering method showed significantly better shoreline detection results than the other filter methods. It was concluded that this method would be useful for detecting and monitoring the shoreline edge in Tanjung Piai.