InGaAs Detector Research Articles

Design of EPICS and Web-Based Remote Control Software of Near-Infrared Sky Brightness Monitor in Antarctica

The Near-infrared Sky Brightness Monitor (NIRBM) aims to measure the middle infrared sky background in Antarctica. The NIRBM mainly consists of an InGaAs detector, a chopper, a reflector, a cooler and a black body. The reflector can rotate to scan the sky with a field of view ranging from 0{\deg} to 180{\deg}. Electromechanical control and weak signal readout functions are accomplished by the same circuit, whose core chip is a STM32F407VG microcontroller. Considering the environment is harsh for humans in Antarctica, a multi-level remote control software system is designed and implemented. A set of EPICS IOCs are developed to control each hardware module independently via serial port communication with the STM32 microcontroller. The tornado web framework and PyEpics are introduced as a combination where PyEpics is used to monitor or change the EPICS Process Variables, functioning as a client for the EPICS framework. Tornado is responsible for the specific operation process of inter-device collaboration, and expose a set of interfaces to users to make calls. Considering the high delay and low bandwidth of the network environment, the tornado back-end is designed as a master-and-agent architecture to improve domestic user experience. The master node is deployed in Antarctic while multiple agent nodes can be deployed domestic. The master and agent nodes communicate with each other through the WebSocket protocol to exchange latest information so that bandwidth is saved. The GUI is implemented in the form of single-page application based on the Vue framework which communicates with tornado through WebSocket and AJAX requests. The web page integrates device control, data curve drawing, alarm display, auto observation and other functions together.

Highly sensitive long range surface plasmon based liquid sensor by shining the radially polarized light in bimetallic taper fiber structure

A new approach towards the enhancement of sensitivity in fiber optic liquid sensor is proposed, designed and simulated using the long range surface plasmon resonance technique shining the radially polarized light in bimetallic fiber structure, which comprises a fiber core coated with 40 nm and 10 nm thin Ag and Au layer respectively. The radially outward field distribution of the radially polarized light enables the multiple point plasmonic interaction on the whole fiber periphery which enhances the sensitivity as well as the dynamic range of refractive index sensing through the proposed sensor. A 13 times and 25 times better sensitivity has been estimated using NaCl and KCl solution as compared with the existing articles till date using p-polarized light. Minimum measurable concentration is 0.5 g/l and 1 g/l for NaCl and KCl solutions for a minimum change in output power of 30.04 μW and 25.60 μW respectively using InGaAs detector. With enhanced sensitivity and higher dynamic range of refractive index, this new idea explores the new avenues in the field of fibre optic liquid sensing applications.

Single-defect spectroscopy in the shortwave infrared

Chemical defects that fluoresce in the shortwave infrared open exciting opportunities in deep-penetration bioimaging, chemically specific sensing, and quantum technologies. However, the atomic size of defects and the high noise of infrared detectors have posed significant challenges to the studies of these unique emitters. Here we demonstrate high throughput single-defect spectroscopy in the shortwave infrared capable of quantitatively and spectrally resolving chemical defects at the single defect level. By cooling an InGaAs detector array down to −190 °C and implementing a nondestructive readout scheme, we are able to capture low light fluorescent events in the shortwave infrared with a signal-to-noise ratio improved by more than three orders-of-magnitude. As a demonstration, we show it is possible to resolve individual chemical defects in carbon nanotube semiconductors, simultaneously collecting a full spectrum for each defect within the entire field of view at the single defect limit.

Design and Characterization of the Multi-Band SWIR Receiver for the Lunar Flashlight CubeSat Mission

Lunar Flashlight (LF) is an innovative National Aeronautics and Space Administration (NASA) CubeSat mission that is dedicated to quantifying and mapping the water ice that is harbored in the permanently shadowed craters of the lunar South Pole. The primary goal is to understand the lunar resource potential for future human exploration of the Moon. To this end, the LF spacecraft will carry an active multi-band reflectometer, based on an optical receiver aligned with four high-power diode lasers emitting in the 1 to 2-μm shortwave infrared band, to measure the reflectance of the lunar surface from orbit near water ice absorption peaks. We present the detailed optical, mechanical, and thermal design of the receiver, which is required to fabricate this instrument within very demanding CubeSat resource allocations. The receiver has been optimized for solar stray light rejection from outside its field of view, and utilizes a 70 × 70-mm, aluminum, off-axis paraboloidal mirror with a focal length of 70 mm, which collects the reflected light from the Moon surface onto a single-pixel InGaAs detector with a 2-mm diameter, hence providing a 20-mrad field of view. The characterization of the flight receiver is also presented, and the results are in agreement with the expected performance obtained from simulations. Planned to be launched by NASA on the first Space Launch System (SLS) test flight, this highly mass-constrained and volume-constrained instrument payload will demonstrate several firsts, including being one of the first instruments onboard a CubeSat performing science measurements beyond low Earth orbit, and the first planetary mission to use multi-band active reflectometry from orbit.

结电容对不同光敏元尺寸InGaAs探测器I-V特性测试的影响

结电容对不同光敏元尺寸InGaAs探测器I-V特性测试的影响

Non-invasive soft breakdown localisation in low k dielectrics using photon emission microscopy and thermal laser stimulation

For the first time a non-invasive localisation of a soft breakdown (SBD) is shown. The localisation is completed on fully functional back end of line (BEOL) test structures. The test structures used, provided by the interuniversity microelectronics centre (imec), are metal insulator semiconductor (MIS) structures. The low k dielectric within the test structures is SiOCH type with OSG 2.0 (k = 2.0), 45% porosity and 40 nm thickness. Contacless faul isolation methods have been evaluated for detecting a SBD on these structures.We evaluated photon emission microscopy (PEM) with two different signal detectors, the Si – CCD and the InGaAs camera.A proof of concept for detecting a SBD with themal laser stimulation (TLS) is presented.Using a Si – CCD and up to 2000 s integration time, photon emission (PE) signals from a 2 μm × 2 μm test structure with a leakage current less than 1 nA are presented.With the InGaAs detector a localised SBD from a 2 μm × 2 μm test structure with a leakage current of 100 pA is shown.The detected SBDs have a resistance of 33 GΩ and 260 GΩ respectively thus the level of degradation is several orders of magnitude lower compared to a hard breakdown (HBD). Up to now it was only possible to localise defects at higher levels of degradation. Due to the high energy at these levels, original defect signatures for SBD are usually destroyed. To better control the process of degradation, a way to nearly freeze the degradation process is shown. This method was used to detect a 1 nA leakage current of a 2 μm × 2 μm structure with a resistance of 35 GΩ using optical beam induced resistance change (OBIRCH) which is a similar contactless fault isolation (CFI) method to TLS. The presented SBD localisations allow to plan accurate physical preparations for the first time.Physical analysis of PEM localised SBD and HBD have been performed and compared.Possibilities to further improve the presented SBD detection levels are discussed for OBIRCH. Limitations for PEM with Si – CCD and InGaAs detectors as a CFI for SBDs are discussed.

Influence of Incident Wavelength and Detector Material Selection on Fluorescence in the Application of Raman Spectroscopy to a Fungal Fermentation Process.

Raman spectroscopy is a novel tool used in the on-line monitoring and control of bioprocesses, offering both quantitative and qualitative determination of key process variables through spectroscopic analysis. However, the wide-spread application of Raman spectroscopy analysers to industrial fermentation processes has been hindered by problems related to the high background fluorescence signal associated with the analysis of biological samples. To address this issue, we investigated the influence of fluorescence on the spectra collected from two Raman spectroscopic devices with different wavelengths and detectors in the analysis of the critical process parameters (CPPs) and critical quality attributes (CQAs) of a fungal fermentation process. The spectra collected using a Raman analyser with the shorter wavelength (903 nm) and a charged coupled device detector (CCD) was corrupted by high fluorescence and was therefore unusable in the prediction of these CPPs and CQAs. In contrast, the spectra collected using a Raman analyser with the longer wavelength (993 nm) and an indium gallium arsenide (InGaAs) detector was only moderately affected by fluorescence and enabled the generation of accurate estimates of the fermentation’s critical variables. This novel work is the first direct comparison of two different Raman spectroscopy probes on the same process highlighting the significant detrimental effect caused by high fluorescence on spectra recorded throughout fermentation runs. Furthermore, this paper demonstrates the importance of correctly selecting both the incident wavelength and detector material type of the Raman spectroscopy devices to ensure corrupting fluorescence is minimised during bioprocess monitoring applications.

Testing irradiance and radiance methods for absolute radiation thermometry based on InGaAs detectors in the NIR at CEM/CSIC

After measuring thermodynamic temperatures in the range from 900 °C to 2500 °C, The Centro Español de Metrologia (CEM) in collaboration with the Instituto de Óptica of the Consejo Superior de Investigaciones Científicas (IO-CSIC) are currently involved in the measurement of thermodynamic temperatures down to 400 °C using radiometers based on InGaAs detectors with central wavelengths in the near-infrared spectral range (NIR). This communication summarizes the progress towards the extension of absolute radiation thermometry measurement range to lower temperatures.

Optical Pumped Gesn Waveguides Room Temperature Amplified Spontaneous Emission Observation

The successful epitaxial growth of Ge-on-Si has opened a new gateway for Si-based laser research. Ge is not a direct band gap material, however it possible to induce Ge towards direct band emission due to the small band gap energy differences between the direct and indirect. Recently lasing cavities have been successfully engineered by introducing tensile strain to the Ge lattice or through Sn alloying. The two methods have similar effects, lowering both direct and indirect band gaps of Ge with different rate. For a critical or higher Sn content, the direct band can become the lowest gap. This research is motivated by GeSn alloys with high potential to overcome many difficulties such as integration scale limits, excessive cost, extreme operating condition, etc in terms of engineering Si-based lasers. In this work, we explore the properties of optical emission from optically-pumped waveguides fabricated from GeSn alloys with Sn concentrations below the direct band gap transition. The fabrication process of the GeSn waveguides starts with growing undoped Ge buffer layers on Si (100) substrates using gas source molecular epitaxy with Ge4H10 and the wafers were annealed in situ at 650 °C for 3 min. After aqueous HF solution Ge virtual substrates cleaning, flows 5% Ge2H6 in H2 at 30 mTorr for 5 min for additional surface cleaning. Then the mixtures of Ge3H8, SnD4, and P(GeH3)3 (resulting in a concentration of 4.4% Sn in this research study) grows n-type doped GeSn films around 285-335 °C. On the GeSn surface, strip waveguides with width 3 μm and length 4 mm were BCl3 reactive ion etched by using standard UV contact photolithography. With plasma-enhanced chemical vapor deposition, a thickness of 180nm SiO2 was deposited for surface passivation after downright Ge buffer layer to Si interface etching process. For the experimental procedures, the waveguide with both end mirror polished, and one end is Al deposited to form the cavity. The other open end is aligned with a lens fiber as the collection prosses of the output. A 976 nm laser beam is shaped into a line and focused onto the top surface of the waveguide. The signal is collected by an optical fiber and sent through a grating spectrometer with an extended InGaAs detector for spectrum analysis or direct into the detector for power measurements. For spectral analysis each data points are generated by wavelength corresponded grating reflection angle and its amplitude within still pump level and sets of data are measured at different pump levels. The power curve measurements signal amplitude is mapped directly from different pump levels. Room temperature is maintained by using active cooling for all pumping operations. At 4.4% Sn, the material still has indirect bandgap as the lowest band and direct band energy is slightly above. This results in emission curves due to the indirect band gap and the direct band gap at lower output power from the spectrum analysis. It also shows that with increasing the pump level, the ratio between the emission power of the two processes increases and the two emission peaks separate further as the pump power is increased. Meanwhile the emission power from our waveguide versus pump power shows an exponential dependence, indicating the population inversion and optical gain at targeted spectrum reign. In this research the amplified spontaneous emission and its spectrum from optically pumped GeSn waveguide on Si at room temperature has been successfully observed. GeSn with 4.4% Sn content provides promising results as a gain material at mid-IR range.

Development of a Long-Wave Infrared Band-Edge (LWIR BE) thermometry instrument.

Accurate measurement of substrate temperature is one of the most critical process control parameters for molecular beam epitaxy (MBE) growth. Band-edge thermometry instruments have proven to be a valuable tool for process control during MBE growth of semiconductor films, providing as high as ±1 °C temperature resolution. The increasing use of InAs, GaSb, and AlSb iii-v materials necessitates a method for accurately measuring the temperature of their closely lattice-matched GaSb substrates. Current-technology instruments typically rely on InGaAs detector materials which have a maximum wavelength λ detection of ∼1.7 μm, but GaSb substrates have a band gap energy corresponding to λ > 2 μm. A band-edge thermometry instrument capable of λ > 2 μm has been developed using an InAs/InGaSb strained-layer superlattice detector sensitive to 2-9.5 μm long-wave IR wavelengths.

Spectral features of the Stokes part of supercontinuum generated by femtosecond light pulses in selected oxide crystals: A comparative study

The peculiarities of the Stokes part of supercontinuum (SC) generated by femtosecond light pulses at wavelength 800 nm in single crystals of Gd2SiO5(GSO), Ca4GdO(BO3)3(GCOB), Gd3Ga5O12(GGG), LiTaO3 (LTO) and LuVO4 (LVO) were investigated. Spectral bandwidth and intensity of SC were measured as a function of energy of incident 100 fs pulses employing a grating spectrograph coupled with an InGaAs detector and spatial characteristics of the beam inside crystal samples were monitored perpendicularly to the direction of propagation and recorded using an optical microscope coupled with a camera. It was found that spectral widths of the Stokes part of SC increase markedly with increasing energy of incident pulses for all crystals under study. For fixed focusing conditions the spectral widths of generated SC in GSO, GCOB and GGG wide band-gap crystals are relatively large with cut-off wavelengths close to 1500 nm. Bandwidths of SC generated in LVO and LTO crystals, characterized by band-gaps Eg inferior to three times incident photon energy, are markedly smaller with cut-off wavelengths of 1300 nm and 1150 nm, respectively. Increase of incident pulse energy affects SC spectra giving rise to plateau-like regions stretching to ca 1000 nm.

A 1064 nm Dispersive Raman Spectral Imaging System for Food Safety and Quality Evaluation

Raman spectral imaging is an effective method to analyze and evaluate the chemical composition and structure of a sample, and has many applications for food safety and quality research. This study developed a 1064 nm dispersive Raman spectral imaging system for surface and subsurface analysis of food samples. A 1064 nm laser module is used for sample excitation. A bifurcated optical fiber coupled with Raman probe is used to focus excitation laser on the sample and carry scattering signal to the spectrograph. A high throughput volume phase grating disperses the incoming Raman signal. A 512 pixels Indium-Gallium-Arsenide (InGaAs) detector receives the dispersed light signal. A motorized positioning table moves the sample in two-axis directions, accumulating hyperspectral image of the sample by the point-scan method. An interface software was developed in-house for parameterization, data acquisition, and data transfer. The system was spectrally calibrated using naphthalene and polystyrene. It has the Raman shift range of 142 to 1820 cm−1, the spectral resolution of 12 cm−1 at full width half maximum (FWHM). The spatial resolution of the system was evaluated using a standard resolution glass test chart. It has the spatial resolution of 0.1 mm. The application of the system was demonstrated by surface and subsurface detection of metanil yellow contamination in turmeric powder. Results indicate that the 1064 nm dispersive Raman spectral imaging system is a useful tool for food safety and quality evaluation.

Multi-frame linear regressive filter for the measurement of infrared pixel spatial response and MTF from sparse data.

A challenging point in the prediction of the image quality of infrared imaging systems is the evaluation of the detector modulation transfer function (MTF). In this paper, we present a linear method to get a 2D continuous MTF from sparse spectral data. Within the method, an object with a predictable sparse spatial spectrum is imaged by the focal plane array. The sparse data is then treated to return the 2D continuous MTF with the hypothesis that all the pixels have an identical spatial response. The linearity of the treatment is a key point to estimate directly the error bars of the resulting detector MTF. The test bench will be presented along with measurement tests on a 25 μm pitch InGaAs detector.

Image-guided Removal of Interproximal Lesions with a CO2 Laser.

Recent studies have shown that near-IR (NIR) imaging methods such as NIR reflectance can be used to image lesions on proximal surfaces, and optical coherence tomography (OCT) can be used to measure the depth of those lesions below the tooth surface. These imaging modalities can be used to acquire high contrast images of demineralized tooth surfaces, and 2-D and 3-D images can be extracted from this data. At NIR wavelengths longer than 1200-nm, there is no interference from stains and the contrast is only due to the increased light scattering of the demineralization. Previous studies have shown that image-guided laser ablation can be used to remove occlusal lesions, but its use for the removal of subsurface lesions on proximal surfaces has not been investigated. The objective of this study is to demonstrate that simultaneously scanned NIR and CO2 lasers can be used to selectively remove natural and artificial interproximal caries lesions with minimal damage to sound tooth structure. In this study, images of simulated and natural interproximal lesions on extracted teeth were imaged using a digital microscope, a scanned 1460-nm superluminescent laser diode with an InGaAs detector and a cross polarization OCT system operating at 1300-nm. The lesions were subsequently removed with a CO2 laser operating at 9.3-µm and the dental handpiece and the volume of sound tissue removed was compared.

InGaAsディテクタを用いたLSIエミッション裏面解析ツール (特集 LSI品質の保証のための提案)

InGaAsディテクタを用いたLSIエミッション裏面解析ツール (特集 LSI品質の保証のための提案)

基于InGaAs探测器的日光条件光子计数实验

基于InGaAs探测器的日光条件光子计数实验

On the InGaAs-based Photodetection Circuit for Scanning Near-Infrared Signal in the Wavelength Range of 1.0-2.0μm

Detection of scanning long wave near-infrared (NIR) signal is critical in numerous applications spanning the fields of military, industry, agriculture, environment, and medicine. In this paper, we present a low cost, high performance InGaAs-based photoelectric conversion and amplification circuit for detecting scanning NIR signal in the wavelength range of 1.0-2.0 μm. With a special focus on reducing the influence of dark current and dark current noise for improved detector efficiency and precision, this proposed circuit features a photovoltaic preamplifier, a low-pass filter, and a temperature control unit; the signal gain, the bandwidth and the noise of the entire circuit is tuned for the signal spectrum of interest. In particular, to make the InGaAs detector operate at the target temperature with little fluctuation, a low-cost closed-loop temperature control circuit is designed that delivers temperature control accuracy of ±0.1°C. Both simulation and experimental results have confirmed that the proposed detection circuit meets the specific performance requirements for its intended use in spectrometer.

InGaAs探测器的盲元分析及P电极优化

InGaAs探测器的盲元分析及P电极优化

Methane absorption spectroscopy on a silicon photonic chip

Infrared tunable diode-laser absorption spectroscopy (IR-TDLAS) is an enabling technology for trace-gas detection, with applications ranging from air-quality monitoring to medical diagnostics. However, such sensors typically utilize discrete optical components that pose practical cost limits for large-scale network deployments. Here, we leverage silicon photonics technology to demonstrate IR-TDLAS on an integrated CMOS-compatible platform for methane (CH4) spectroscopy. Using near-IR (1650 nm) light from a distributed-feedback laser and an uncooled InGaAs detector, the evanescent optical field of a high-index contrast nanoscale silicon waveguide is used to probe ambient CH4, yielding Gaussian-noise-limited sub-100 parts-per-million by volume detection limits. Our results demonstrate the feasibility of chip-scale photonic integration for realizing compact, cost-effective, and versatile gas sensors capable of tackling diverse energy and environmental challenges, such as natural-gas leak quantification and localization for fugitive-emissions monitoring.

Traceable spectral irradiance measurements in photovoltaics: Results of the PTB and JRC spectroradiometer comparison using different light sources

JRC ESTI and PTB performed a comparison of their respective reference standard spectroradiometers, aiming at improving knowledge on equivalence of spectral irradiance measurements and resulting uncertainty in calibration of photovoltaic devices. The comparison was conducted at the JRC premises using different light sources in order to test the reference instruments under various real-world operating conditions. The measured sources included four standard lamps (two calibrated by PTB and two calibrated by NPL), global natural sunlight under clear sky conditions, a steady-state xenon-halogen solar simulator for solar cell calibration (Wacom) and a steady-state xenon large area solar simulator (Apollo). The PTB system is composed of three compact array spectroradiometers (CAS) equipped with Si, InGaAs, and extended range InGaAs detectors, respectively, in order to cover the wavelength range from 250 to 2150nm. The JRC-ESTI used a rotating grating spectroradiometer composed of a single stage monochromator and a Si-PbS sandwich detector in order to cover a wavelength range from 300 to 2500nm, and, for the natural sunlight measurements, additionally a system composed of three compact array spectroradiometers covering the wavelength range from 300to1700nm. Before the comparison all instruments were calibrated in house by the owning institution using their respective procedures and traceability chains. The measured spectra were compared and deviations were found to generally be within combined uncertainties. Finally, exemplary spectral mismatch calculations were made to evaluate the impact of the deviations in spectral measurements on PV devices calibration. The deviations were mostly less than 0.5%, but in some cases exceeded 1%.