Emerging Imaging and Sensing Technologies for Security and Defence VI

In recent years the Earth observation (EO) programmes of the European Space Agency (ESA) have been dramatically extended. They now include activities that cover the entire spectrum of the wide EO domain, encompassing both upstream and downstream developments, i.e. related to flight elements (e.g. sensors, satellites, supporting technologies) and to ground elements (e.g. operations, data exploitation, scientific applications and services for institutions, businesses and citizens). In the field of EO research missions, ESA continues the successful series of Earth Explorer (EE) missions. The last additions to this series include missions under definition, namely Harmony (the tenth EE) and four candidates for the 11th EE: CAIRT (Changing Atmosphere InfraRed Tomography Explorer), Nitrosat (reactive nitrogen at the landscape scale), SEASTAR (ocean submesoscale dynamics and atmosphere-ocean processes), WIVERN (Wind Velocity Radar Nephoscope). On the smaller programmatic scale of the Scout missions, ESA is also developing two new missions: ESP-MACCS (Earth System Processes Monitored in the Atmosphere by a Constellation of CubeSats) and HydroGNSS (hydrological climate variables from GNSS reflectometry). Another cubesat-scale mission of technological flavor is also being developed, Φ-sat-2. Furthermore, in collaboration with NASA, ESA is defining a Mass change and Geosciences International Constellation (MAGIC) for monitoring gravity variations on a spatio-temporal scale that enables applications at regional level, continuing - with vast enhancements - the successful series of gravity mapping missions flown in the last two decades. The key features of all these missions will be outlined, with emphasis on those relying on optical payloads. ESA is also developing a panoply of new missions for other European institutions, namely Eumetsat and the European Union, which will be briefly reviewed too. These operational-type missions rely on established EO techniques. Nonetheless some new technologies are applied to expand functional and performance envelopes. A brief resume’ of their main features will be provided, with emphasis on the new Sentinel missions for the EU Copernicus programme.

Optronic systems for the defence market are available from the UV to the LWIR wavelengths but the ideal band very much depends on the particular application and their environment. This lecture will cover some of the more important features of each type of optronic sensor and using examples from the experience gained over many years of system development by Tecnobit for Airborne, Navel and Land sectors, suggests some broad recommendations.

Today, space is experiencing a revolution: from large space agencies, multimillion dollar budgets, and big satellite missions to spin-off companies, moderate budgets, and fleets of small satellites. Some have called this the “democratization” of space, in the sense that it is now more accessible than it was just a few years ago. To a large extent, this revolution has been fostered on one side by the standardization of the platforms’ mechanical interfaces, and on the other side by the technology developments coming from mobile communications. Standard platform’s mechanical interfaces have led to standard orbital deployers, and new launching capabilities. The technology developed for cell phones has brought more computing resources, with less power consumption and volume. Small satellites are used as pure technology demonstrators, for targeted scientific missions, mostly Earth Observation, some for Astronomy, and they are starting to enter in the field of communications, as huge satellite constellations are now becoming more possible. In this lecture, the most widely used nano/microsats form factors, and its main applications will be presented. Then, the main Scientific Earth Observation and Astronomy missions suitable to be boarded in SmallSats will be discussed, also in the context of the rising Constellations of SmallSats for Communication. Finally, the nanosat program at the Universitat Politècnica de Catalunya (UPC) will be introduced, and the results of the FSSCAT mission will be presented.

This paper discusses the use of smoke obscurants as countermeasures against high energy lasers (HEL). Potential success of the smoke does not depend only the performance of the smoke. The transmission loss in the smoke is part of a chain of system components, including warning sensors, smoke launchers, etc.. The core of the paper deals with experimental work on the following research questions: - Does smoke attenuate an incoming beam of a HEL? - Does the HEL affect the smoke itself? The experimental set-up with the TNO 30kW HEL and the scale model for the smoke transmission path will be shown. Selected experimental results will be shown and discussed. Finally we will compare the results to theoretical calculations and we will analyse the properties of an ideal HEL attenuation smoke.

Time correlated single photon counting (TCSPC) lidar is an attractive technique that allows high sensitivity, high range resolution lidar measurements. This is becoming an established technology in the near and short wave IR (NIR and SWIR) wavelength regions. Extension of TCSPC lidar to longer wavelength would benefit e.g. through possibilities for range resolved gas concentration measurements and by improved transmission through smoke and haze. Detection of single photons in the mid IR is however difficult because of the low photon energy. Up-conversion through sum frequency generation (SFG) with a NIR photon transfers the mid IR photons to shorter wavelength and allows detection with established room temperature silicon single photon avalanche detectors (SPAD). To reach high up conversion efficiency important factors are high NIR pump intensity, long interaction length and high nonlinearity. Engineered quasi phase-matched (QPM) nonlinear crystals can provide walk off free interaction with high nonlinearity at any desired wavelength within the transparency range of the crystal. By placing the nonlinear crystal inside the cavity of a continuous wave laser the high intra cavity power allows for high conversion efficiency without prior knowledge of the propagation delay of the mid IR photons. The concept is demonstrated through short range 3 µm lidar measurements against diffusely reflecting targets, using a PPRKTP nonlinear crystal inside a Nd:YVO4 laser cavity for up conversion to 790 nm. The measurements show 84 ps FWHM temporal width of the lidar response and below 1 mm range precision, as demonstrated by scanning 3D targets. The main challenge encountered has been the removal of leaked photons from the NIR pump diodes for the Nd laser, which seems to have some emission at the SFG wavelength.

Single photon-counting avalanche photo-diode (SPAD) can measure the photon flux from uncorrelated single photons. In present work, we show how the sensor photon count rate is related to the intensity or the radiant flux that is reflected from surfaces in the sensor’s field of view and incident on the sensor array. After a brief theoretical discussion of photon flux imaging, we examine various de-noising strategies and the effect of motion blur. Finally, we present the application of a fast super-resolution neural network (FSRCNN) to scale image by a scaling factor of 3× to obtain super-resolution images (32 × 32 → 96 × 96).

We show a novel architecture for massively parallel FMCW LiDAR based on multiheterodyne mixing of two triangular chirped soliton microcombs generated in integrated Si3N4 microresonators using a single laser source and a single coherent receiver. We demonstrate a proof of concept experiment with 5.6 MPix/s acquisition rates.

We demonstrate an optical ranging technique using stationary light with a broadband spectral envelop, based on a sub-threshold laser diode, with the time-of-flight information extracted from thermal photon bunching. In contrast, conventional ranging techniques require a light source with timing modulation in intensity, phase, or frequency, with which to correlate the reference and probe-to-target light beams. This timing modulation may allow a third party to identify the presence and location of the ranging instrument. A third party with information of the timing modulation specifications may also be able to reproduce and transmit a similar light beam to the instrument source, resulting in a false ranging measurement. In comparison, our stationary broadband light source will be more difficult to detect by a third party due to the lack of distinct features in temporal and spectral domains. And the measured thermal photon bunching signal used to extract the ranging information is an intrinsic quantum property of thermal light which cannot be replicated by a third party and is hence secured.

Timing measurements with single photon detectors have acquired a prominent role in many applications, especially where they allow the recovery of faint light signals in harsh environments. We present a new fully-integrated multifunctional Time-to-Amplitude Converter (TAC), featuring 8 channels with a full scale range up to 100ns and a linearity better than 1% of the LSB peak to peak. The maximum speed of the converter is obtained in the Fast-TAC configuration (80MHz), while the precision of the converter can be maximized by exploiting multiple channels to perform the same conversion, achieving an overall jitter as low as 1.4ps.

Detection and geo-positioning of laser sources by the collection of atmospherically scattered laser light is an important sensing capability for applications such as early identification of lasers that can temporarily blind pilots during the final phase of aircraft landing or identification of active laser sensors in the environment of operation. Recent work has shown that lasers can be detected through direct detection of Rayleigh scattering events. However, Rayleigh scattering intensity is strong at short wavelengths, but rapidly degrades as wavelength increases toward the near infrared. In this work we performed simulations of Mie scattering of laser beams interacting with single, micron-sized particles and validated these simulations by constructing a laboratory-scale testbed to directly measure the scattering intensity as a function of scattering angle and laser wavelength. Experimental results showed that estimated Mie scattering intensity from our simulations were in good agreement with experimental measurements. At 40 ms exposure time, we were able to detect laser light in a scene at a scattering angle up to 30 degrees with >99% detection probability and <1% false positive probability. Furthermore, consistent accurate localization of the laser within the frame was achieved with exposure time of 100 ms. Looking forward, we plan to use this approach to develop a sensor that will enable us to detect and locate disruptive near infrared lasers.

The inherent differences of the Compressed Sensing (CS) imaging technique result in advantages compared to conventional imaging for scenes containing a rather low amount of relevant data. Such information “sparsity” enables the reconstruction of images with a small number of low-resolution measurements, focusing on the relevant information already during the measurement process. The crucial “sparsity” requirement of the CS framework is fulfilled in certain threat detection applications like e.g. solar blind UV missile warning. To assess, whether CS technology is applicable for threat detection, where short acquisition times and robust and reliable detection are a must, we developed a universal framework for the assessment of the performance of compressed sensing algorithms. This framework includes the most promising algorithms from our past performance assessments and a selection of image quality metrics suited for conceivable applications. The currently implemented algorithms are TVAL3, NESTA, FPC and L1-primal-dual algorithms. Because of the structure of the realized framework, the integration of further algorithms and metrics as well as alternative image acquisition approaches is possible. The studied data sets include scenes were the approach of a threat is modelled for our single-pixel-camera setup as well as recordings done with solar blind UV- and IR-imagers that were broken down to single-pixel-measurements of varying compression.

We demonstrate a hybrid photonic integrated laser that exhibits an intrinsic linewidth of 40 Hz, while offering unsurpassed megahertz actuation bandwidth with the tuning range larger than 1 GHz, attained by a DFB laser self-injection locking to a high-Q Si3N4 microresonator with AlN piezoelectrical actuator, allowing both single-line operation and microcomb generation. We develop a compact FMCW LiDAR engine with triangular chirp optical signals at a rate up to 1 MHz, without requiring any linearisation.

A multispectral image camera captures image data within specific wavelength ranges in narrow wavelength bands across the electromagnetic spectrum. Images from a multispectral camera can extract additional information that the human eye or a normal camera fails to capture and thus have important applications in precision agriculture, forestry, medicine, and object identification. Multispectral cameras operating in the visible wavelengths are readily possible due to existing established optical filter technologies. Multispectral imaging in thermal wavelengths (7µm to 14µm) is an emerging research area due to its ability to identify objects precisely from emission spectrum for chemical detection, gas sensing, night vision and surveillance applications. The wavelength filtering in the thermal region requires large number of layers due to the long wavelengths using conventional techniques, and only limited number of materials are suitable for operating in the thermal wavelengths compared to their optical filter counter part in the visible region. The conventional filter technology has challenged the development of multispectral image camera operating in the thermal wavelengths. Here, we explore copper plasmonics on gallium arsenide (GaAs) substrate for the development of multispectral filters in thermal region for the first time. The filter geometry consists of periodic array of holes perforated in copper film deposited on a GaAs substrate and then covered with germanium. The filters were computationally investigated and optimised using finite element methods to find six suitable transmission peak wavelengths and then fabricated using microfabrication techniques. The spectral measurements of fabricated arrays showed a spectral width of around 0.85 µm at full width at half maximum and a 56 % peak transmittance for the filters with peak wavelengths of 8 µm, 9 µm, 10 µm , 11 µm , 12 µm and 13 µm. The filters were then mounted on FLIR lepton thermal sensors and integrated with in-house developed processing electronics to develop a thermal multispectral camera with six bands.

Quartz-enhanced photoacoustic spectroscopy (QEPAS) [1] is one of the most efficient ways to obtain sensitive, selective, robust gas sensors. The main drawback of QEPAS comes from usage of quartz tuning fork (QTF) as a mechanical transducer. QTF is not specifically design for photoacoustic gas sensing and its further integration is limited. As a solution we propose a silicone resonant MEMS based on capacitive transduction mechanism. This sensor, specifically designed for acoustic sensing purposes, can be an efficient transducer for sound wave detection able to advantageously replace a QTF. Capacitive transduction allows reaching high sensitivity of the sensor while choice of silicon is favorable in design flexibility, fabrication maturity, stability and further integration with CMOS electronics. We have developed and fabricated various resonator designs on silicon. Specific designs were created to sensor voltage output using an analytic model developed by our group [2]. Photoacoustic measurement was performed on calibrated mixtures of methane using commercial Eblana distributed feedback laser laser emitting at 1.63 μm. We achieved a reproducible limit of detection on methane: 1000ppmv in 5s for 2f detection and 700ppm in 5s for 1f detection (figure 1) (resonator resonance frequency 22.65 kHz and Q-factor of 250). Then, we compared the experimental results with standard QTF in off-beam configuration for which the limit of detection: 30ppmv in 5s for 2f detection and 25 ppm in 5s for 1f detection. Thus, the difference of detection limit between QTF and MEMS amounts factor 28 for 1f detection and 33 for 2f detection. [1] Kosterev, A. A., Bakhirkin, Y. A., Curl, R. F., & Tittel, F. K. (2002). Quartz-enhanced photoacoustic spectroscopy. Optics letters, 27(21), 1902-1904. [2] Trzpil, Wioletta, et al. "Analytic Optimization of Cantilevers for Photoacoustic Gas Sensor with Capacitive Transduction." Sensors 21.4 (2021): 1489.

Free-Space Optical (FSO) communication is a technology that enables ultra-high-rate data exchange and will be crucial in enabling secure Quantum Key Distribution (QKD) over long distances. However, FSO communication systems are comparatively complex technologies, comprising a variety of subsystems that all have to work together in a coordinated way. Hence, assessing the feasibility of establishing a (classical or quantum) link in a given communication scenario is a difficult task in itself. Here we introduce QCalc, a software tool that aims at easing and streamlining this process, allowing the user to keep track of all the relevant parameters in a link budget. This software computes the total transmissivity, and thus, the signal intensity observed at the receiver for any given parameters of the transceivers and the FSO communication channel. The estimated signal intensity can then be used to compute either the link budget in a classical communication scenario or the secure key rate of a QKD protocol.

GaN laser diodes have the potential to be a key enabler for many quantum technologies since the AlGaInN material system allows for laser diodes to be fabricated over a wide range of wavelengths from ultra-violet to visible. Novel applications for quantum technologies include GaN laser sources for cold-atom interferometry, such as next generation optical atomic clocks, quantum magnetometers, quantum imaging and quantum gravity sensors. GaN allows the development of very high specification laser diode sources that are portable, robust and provide practical solutions that are otherwise unobtainable using more conventional laser sources. Several approaches are taken to achieve the required linewidth, wavelength and power for cold-atom interferometry, including an extended cavity GaN laser diode (ECLD) system, and a distributed feedback (DFB) GaN laser diode with side-wall etched nano-gratings. We report our latest results on a range of AlGaInN diode-lasers targeted to meet optical atomic clock and quantum gravity sensor applications. This includes the [5s2S1/2-5p2P1/2] cooling transition in strontium+ ion optical clocks at 422 nm, the [5s21S0-5p1P1] cooling transition in neutral strontium clocks at 461 nm and the [5s2s1/2 – 6p2P3/2] transition in rubidium at 420 nm.

The Trojan-horse attacks on quantum key distribution (QKD) systems are known to be a threat to secure key sharing between two parties (Alice and Bob). To protect a QKD system against such attacks a variety of passive optical and active optical devices embedded in Alice’s and Bob’s setup are widely used. However, a security analysis against the Trojan-horse attack is required to ensure the unconditional security of a QKD system. We present a security analysis against the Trojan-horse attacks on a practical fiber-based QKD phase-coding system in 400–1700 nm spectral range. The obtained results made it possible to calculate the higher limit of average photon number returned to Eve and the probabilities of Eve’s success of the attack on a particular QKD system.

Harnessing quantum randomness for the generation of random numbers is an important concept crucial for information security and many other computer-related applications. Quantum random number generators (QRNGs) are evolving from bulky, slow, and expensive implementations towards chip-sized devices. Since computers are deterministic devices, and as such incapable of generating randomness, the prevailing modus operandi is that a QRNG is added to a computer, realizing what is known as "probabilistic Turing machine". State-of-the-art QRNGs use different hardware ports (USB, PCIe,...) and manufacturer-specific bit-transfer protocols, which limits their use by both hardware and software developers. In this work we propose an entirely different approach to use of randomness in a general digital environment (computers included), via a new, dedicated logic circuit: the random flip-flop (RFF), which is fully inter-operable with the standard logic circuits and can form an integral part of microprocessors, ultimately as an instruction-set extension. RFFs can be regarded as the missing link that closes the full set of logic elements; we show their use in digital and analog applications. We also build an RFF on a silicon chip using CMOS process. That, in principle, allows having any number of RFFs on a particular chip (e.g. microprocessor, FPGA, ASIC, ...), enabling both a very fast and massively parallel random number generation. Applications are endless, including recent trends in artificial intelligence, biomimetic stochastic computer and graphics processors. Integrated RFF does not need hardware ports nor bit-transfer protocols and allows an easy integration of randomness into higher programming languages.

Additive manufacturing – specifically 3D laser lithography – has become a powerful technology for the fabrication of 3D objects with sub-micrometric resolution. This technique has already been applied in a broad range of fields, including metamaterials, biomedicine, and optics. However, there is a growing interest in the incorporation of new features or functionalities in the printed structures that can open up new opportunities in the field.1,2 The lecture will present our latest advances in the design of functional polymer based photoresists for 3D laser lithography. In particular, a new class of on-demand cleavable materials will be introduced that can be removed after being printed (subtractive manufacturing).3 Futhermore, new photoresists based on stimuli-responsive materials for the preparation of dynamic and programable microstructures will be presented. We believe that these new materials will have significant impact on future applications, where the advantages of high resolution additive and response on-demand can be combined. [1] C. A. Spiegel, M. Hippler, A. Münschinger, M. Bastmeyer, C. Barner-Kowollik, M. Wegener, E. Blasco. Adv Funct Mater, 2020, 30, 1907615. [2] C. Barner-Kowollik, M. Bastmeyer, E. Blasco, G. Delaittre, P. Mueller, B. Richter, M. Wegener. Angew Chem Int Ed, 56, 15828 (2017). [3] R. Batchelor, T. Messer, M. Hippler, M. Wegener, C. Barner-Kowollik, E. Blasco. Adv Mater, 31, 1904085 (2019).

Most state-of the-art personal screening systems require the person under investigation to stand still. This is infeasible, however, for scenarios when high throughput is required, such as in stadiums, for concerts or sports events, with thousands of persons. Modern walk-through scanners also allow for a screening of moving persons. However, these systems reconstruct an image by using multiple-input-multiple-output (MIMO) radars, which require a large number of transmit and receive channels along a two-dimensional array. We propose a novel concept for security screening which does not require the person to stand still and only employs a one-dimensional array: Our approach is built on the use of inverse synthetic aperture radar (ISAR) imaging based on a vertical line array. For the proposed scanning system, this means that the moving person inversely samples a synthetic aperture along the horizontal dimension. Therefore, only the vertical dimension needs to be sampled by an antenna array. In order to reconstruct an image by the ISAR principle, the test subject’s velocity relative to the radar aperture needs to be known. Therefore, we employ an additional radar module in order to measure the person’s velocity, assuming that the person is moving parallel to the aperture plane. Experiments with a mannequin carrying threat objects were performed. The mannequin was moved on a traversing rail and its velocity was estimated by a commercial radar module emitting a chirp sequence signal. The estimation was in good accordance with the rail’s real moving speed. From the velocity estimation, an image was reconstructed along the horizontal direction by the ISAR principle. Along the vertical direction, the focusing was performed using a MIMO line array. That way, and by employing broadband signals, three-dimensional high-resolution images were obtainable. We used a millimeter-wave scanning system with 10 GHz bandwidth (70 GHz – 80 GHz), which allows for an image resolution of a few millimeters. Promising results were obtained from the measurements and different threat objects were made visible.

The Terahertz (THz) region is located between the infrared region and the RF/microwaves one. It’s the bridging region between Electronics (limited by the cutoff frequency of transistors) and Photonics (limited by the low energy). The broad range of potential applications of THz radiation has boosted the research on THz. Efficient coupling of the incoming electromagnetic (EM) radiation is a major challenge in terahertz technology. The THz beam area is usually larger than the detector (typically a Field-Effect Transistor, FET) whose active area is of hundreds of square-microns. Different methods are used to achieve an efficient coupling like the use of antennas integrated with the device, hemispherical silicon lenses placed close to the chip to focus the beam on the detector, and arrays of detectors. However, those methods are costly and complex to implement. Recently, in order to efficiently improve the coupling of the EM radiation and, hence, to increase the sensitivity of terahertz detectors and the resolution of the imaging system, we introduced the use of the terajet effect. It provides a simple method to improve the focusing of the terahertz beam by simply placing a low-loss dielectric particle with wavelength-scaled dimensions in front of the detector area. This makes possible to localize the radiation incident on the detector to sub-wavelength volumes and, thus, to overcome diffraction limitations, matching the size of the field localization region and the size of the sensitive part of both the FET and point-contact detectors. In the present work, we report on resolution enhancement of a terahertz imaging system using the terajet effect. A wavelength-scaled particle (a Teflon cube for simplicity) was used to localize incident radiation to a subwavelength volume and focus it directly onto the object. A strained-silicon modulation field effect transistor was used as a direct detector on an incident terahertz beam at 0.3 THz. At first, the terahertz imaging of the object was performed without the cube. A clear enhancement of the resolution of the terahertz image was obtained when the cube was placed in the focal point of the terahertz beam and in front of the object.

The physical security of government buildings, banks, schools, higher education institutions, train stations, airports and lastly but not least the people within them has been the key for the sustainability of our society. Day after day, technologies have been invented to improve the physical security of buildings. In this paper a Thru-Vision passive imager having a centre frequency of 250 GHz and a bandwidth of 36 GHz was used to scan images and detect different types of hidden objects under clothing. The clothing materials used in the experimental images were made of cotton, wool and leather. Experimental images show that millimetre-wave (MMW) radiations over the band (232-268) GHz can penetrate these materials and detect hidden objects. Experimental results indicate that the transmission over the MMW band is dependent on the clothing material, thickness and moisture content. The images obtained from the Thru-Vision passive imager provide information about the shape, the size and the dimensions of the hidden objects. These objects were a metal plate and a wax plate. Experimental images show that spraying water on textiles increases the loss over the MMW band and makes the objects less visible, but at the same time they remain detectable. Furthermore, the experimental measurements indicate that textiles made of cotton and wool have higher transmissions of MMW radiation and enabling more reliable object detection compared with leather. These findings indicate the potential of the MMW band of the electromagnetic spectrum for offering a non-contact method of screening people, a touchless pat-down security search for use in scenarios where harmful viruses and bacteria may prevail. This capability will increase the detection probabilities and reduce the false positives rates in security screening.

Passive millimeter-wave (PMMW) imaging has been demonstrated to detect a wide variety of hidden objects including handguns, gasoline, alcohols, explosives, knives, and so on. Since the 2000s, plenty of personnel security screening systems have been developed, but it is still difficult to reach the level of large-scale commercial application. There are two primary reasons limiting this technique. The first one is the lack of radiometer hardware performances, such as thermal sensitivity and spatial resolution. The second reason is the insufficiency of the obtained information. The existing systems usually have single polarization, single waveband, single observing direction. When the radiometer hardware performances are given, we can try to improve imaging and detecting performances by using multi-source information. Polarimetric imaging can obtain much more information about observing scenes. Some works have reported polarimetric imaging simulations and multiple linear polarization imaging experiments. However, there is no work reporting the independently circular polarization imaging experiments of indoor body security screening scenes. In this paper, we have constructed a new PMMW imaging system, which can generate circular polarization images. The imaging system mainly contains two circular polarization antennas, a W-band radiometer, a focal plane lens, an arc-shaped orbit for horizontal pixel, a plane reflector for vertical pixel, and a control computer. The radiometer is placed on the base of the arc-shaped orbit. By putting a left-hand or right-hand circularly polarized antenna on the flange of the radiometer, we can acquire the corresponding left-hand or right-hand circular polarization image. Circular polarization imaging experiments of several human security screening scenarios have been conducted and polarization characteristics have been analyzed. The experimental results indicate that circular polarization imaging can obtain different information from linear polarization imaging and can be helpful to improve image quality.

Prospects for the development of devices for visualizing terahertz (THz) radiation sources can be associated with the use of the results of old studies (1965-1978) on the absorption of THz radiation by metal nanoparticles. This "renaissance" demonstrate that metallic nanoparticles can be used as nanotransducers of invisible THz radiation to infrared (IR) radiation detectable by a commercial IR camera. The investigated THz-to-IR converters are matrices that are transparent both in the THz radiation range to be visualized and in the operating range of the IR camera; matrices contain embedded metal nanoparticles. The latter, when irradiated with THz rays, convert the energy of THz photons into heat and become nanosources of IR radiation for the IR camera. In metal nanoparticles, the mechanisms of absorption of THz radiation and its conversion into heat are realized through dissipation of the energy of THz photons due to multiple scattering of electrons, as well as because of excitation of two types of phonons (transverse and longitudinal ones). The conversion of THz energy into the energy of transverse phonons occurs directly, while dissipation and excitation of longitudinal phonons occurs indirectly, through the excitation of Fermi electrons. Polyvinylchloride was chosen as the matrix material, and gold nanoparticles were chosen as nanoparticles-fillers.

We reported electrochemiluminescence (ECL) in which light is emitted from the excited state of a redox-active material generated by electrochemical reactions. We applied AC driven system to enable quick emission response and high emission intensity. In this paper, we report that electrochemically triggered upconverted emission through triplet–triplet energy transfer (TTET) and subsequent triplet–triplet annihilation upconversion (TTA-UC) is observed for the first time in the electrochemiluminescence properties of a Ru complex/diphenylantracene (DPA) containing electrochemical cell.

A unique photocurrent response of a photovoltaic cell using photosynthetic protein bacteriorhodopsin (bR) is similar to that seen in the retinal ganglion cell, therefore, there are considerable interest in utilizing bR in visual sensors. A position sensitive detector (PSD) is a monolithic photosensor utilizing photodiode surface resistance. When a spot light strikes the PSD, an electric charge proportional to the light intensity is generated at the incident position. This electric charge is driven through the resistive layer and collected by two electrodes as photocurrents, while being divided in inverse proportion to the distance between the incident position and each electrode. In this study, we present 1D 10-cm-long PSD based on bR instead of organic semiconducting polymers. A bR-PSD consists of a dip-coated bR film on a high-resistivity indium-tin-oxide (ITO)-PET film, and counter ITO-PET. The position sensitive output signals of the PSD are measured in response to the intensity-modulated light of a green laser. Nonlinearity, δ=2×RMS deviation/full scale, is a measure of the distortion of the sensor output. An acceptable device has nonlinearities of less than 15%. When the position was detected at a beam diameter of φ = 5 mm, 40 mW/cm2, and the measurement interval 1 mm, the nonlinearity was 3.42%. Especially within an area of position detection error of less than 1%, the nonlinearity was 0.33%. When a beam diameter of φ = 1.5 mm and a measurement interval 500 μm, the nonlinearity showed 0.81% within the range of the light receiving centre of 2 cm. It satisfies 15%, which is the allowable range of general nonlinearity. The bR-PSD showed excellent linearity for all increments measured. Notably, the low cost (3 Euro) and simplicity of fabricating bR-PSD, and no requirement for a bias supply are two of the major advantages over conventional semiconductor material.

Infrared (IR) imaging has been an important technology in security and defense applications; however, its market has been expanding over years. Recently, the share of glass materials, such as chalcogenide glass, has been increasing in the IR optics market. This is because chalcogenide glass can transmit IR light and, thus, can be readily utilized in IR optics via press molding. For the IR optics market, Nippon Electric Glass Co., Ltd. has been developing an optical glass for the IR region. Herein, we introduce our novel IR-transmitting glass material (FI-02) and an IR lens unit made of FI-02. The most effective characteristic of FI-02 is its IR transmittance. It can transmit up to 20 µm wavelength IR light, and it has a very wide transmittance spectrum in the IR region compared to a germanium single crystal and conventional chalcogenide glass; therefore, it can be considered that FI-02 exhibits the best IR transmittance performance in the world. In addition, FI-02 has a high refractive index of 3.47 (at 10 µm wavelength). This is the highest refractive index among glass materials. Moreover, unlike the conventional chalcogenide glass, FI-02 does not include any harmful substances. To investigate FI-02’s performance as an IR lens material, we made two types of IR lens units, FL = 10.5 mm (Standard type) and FL = 2.04 mm (Super wide-angle type). Using the Standard type lens unit, we could capture an IR image with a better contrast than those captured using germanium or conventional chalcogenide glass lenses. Using the Super wide-angle type, we could capture a wider and less-distorted IR image because of FI-02’s high refractive index and easy formation of an aspherical shape by press molding. We believe that FI-02 is a superior IR optics material, and it contributes to improving performance and productivity of IR optics.

The paper discusses the development and application of nanostructured surface systems for a wide range of applications. By programming the parameters of the CAA-PVD (Controled Accelerated Arc-PVD) Deposition process, it becomes possible to effectively control the performance properties of surface modifying systems and products with such systems. Modification of the surface properties of products such as cutting tools, friction pairs and medical implants provides an optimal combination of properties such as surface hardness and plasticity, high adhesion to the substrate and low adhesion to the counterbody material. The strict determinism of the process parameters allows it to be included in the automatic control system of modern manufacturing with significant energy savings and a high level of environmental safety.

A new method for determining surface roughness based on improving the kinematics of the milling cutter movement during micro-cutting has the advantage of the precise spatial position of the micro cutter edge. A change in the components of the speed of movement and rotation during a complex movement of the cutter changes the mechanism of plunging of the cutting edge into the workpiece material. Based on the model developed in this work, the kinematic parameters of the cutter were determined, and new relationships between the cutter geometry and parameters of the technological process were discovered. The revealed new relationships made it possible to determine not only the mechanism of chip formation but also the dimensions of damages to the workpiece surface during plunger cutting.

In this work, a new mathematical model for determining the mechanism of plunging the cutting edge of end mills with a stable passage of the cutting into the workpiece material has been developed. The new mathematical model describes the chip width as a function of the feed rate, the number of teeth and the cutter diameter. The present work shows that the theoretical value of the width of the cut layer can be used as a key parameter controlling the cutting force and as a key factor determining the plunging mechanism. A comparison of model results with experimental data has shown that modeled and experimental heights of microroughness in the stable cutting sections are in agreement within 0.05 μm that indicates the high accuracy of the developed mathematical model.