Phosphorus-based heterojunction tunnel field-effect transistors: from atomic insights to circuit renovations.

Tunnel field-effect transistors (TFETs) are gaining interest for low-power applications, but challenges like poor drive current, delayed saturation, and ambipolarity can hinder their performance. This work proposes a dopingless heterojunction TFET (DL-HTDET) utilizing advanced materials, all based on phosphorus, to address these issues. Our approach involves a comprehensive and accurate analysis of the DL-HTDET's behavior.

Ultra-broadband spectroscopy using a 2-11.5 µm IDFG-based supercontinuum source.

Supercontinuum sources based on intrapulse difference frequency generation (IDFG) from mode-locked lasers open new opportunities in mid-infrared gas spectroscopy. These sources provide high power and ultra-broadband spectral coverage in the molecular fingerprint region with very low relative intensity noise. Here, we demonstrate the performance of such a light source in combination with a multipass cell and a custom-built Fourier transform spectrometer (FTS) for multispecies trace gas detection.

Real-Time Measurement of CH in Human Breath Using a Compact CH/CO Sensor.

The presence of an elevated amount of methane (CH) in exhaled breath can be used as a non-invasive tool to monitor certain health conditions. A compact, inexpensive and transportable CH sensor is thus very interesting for this purpose. In addition, if the sensor is also able to simultaneously measure carbon dioxide (CO), one can extract the end-tidal concentration of exhaled CH.

LazyFox: fast and parallelized overlapping community detection in large graphs.

The detection of communities in graph datasets provides insight about a graph's underlying structure and is an important tool for various domains such as social sciences, marketing, traffic forecast, and drug discovery. While most existing algorithms provide fast approaches for community detection, their results usually contain strictly separated communities. However, most datasets would semantically allow for or even require overlapping communities that can only be determined at much higher computational cost.

Mid-infrared supercontinuum-based Fourier transform spectroscopy for plasma analysis.

Broadband mid-infrared (MIR) spectroscopy is a well-established and valuable diagnostic technique for reactive plasmas. Plasmas are complex systems and consist of numerous (reactive) types of molecules; it is challenging to measure and control reaction specificity with a good sensitivity. Here, we demonstrate the first use of a novel MIR supercontinuum (SC) source for quantitative plasma spectroscopy.

Fourier transform spectrometer based on high-repetition-rate mid-infrared supercontinuum sources for trace gas detection.

We present a fast-scanning Fourier transform spectrometer (FTS) in combination with high-repetition-rate mid-infrared supercontinuum sources, covering a wavelength range of 2-10.5 µm. We demonstrate the performance of the spectrometer for trace gas detection and compare various detection methods: baseband detection with a single photodetector, baseband balanced detection, and synchronous demodulation at the repetition rate of the supercontinuum source.

Fourier transform and grating-based spectroscopy with a mid-infrared supercontinuum source for trace gas detection in fruit quality monitoring.

We present a multi-species trace gas sensor based on a fast, compact home-built Fourier transform spectrometer (FTS) combined with a broadband mid-infrared supercontinuum (SC) source. The spectrometer covers the spectral bandwidth of the SC source (2 - 4 µm) and provides a best spectral resolution of 1 GHz in 6 seconds. It has a detection sensitivity of a few hundred of ppbv Hz for different gas species.

Broadband Time-Resolved Absorption and Dispersion Spectroscopy of Methane and Ethane in a Plasma Using a Mid-Infrared Dual-Comb Spectrometer.

Conventional mechanical Fourier Transform Spectrometers (FTS) can simultaneously measure absorption and dispersion spectra of gas-phase samples. However, they usually need very long measurement times to achieve time-resolved spectra with a good spectral and temporal resolution. Here, we present a mid-infrared dual-comb-based FTS in an asymmetric configuration, providing broadband absorption and dispersion spectra with a spectral resolution of 5 GHz (0.

Sensitive multi-species trace gas sensor based on a high repetition rate mid-infrared supercontinuum source.

We present a multi-species trace gas sensor based on a high-repetition-rate mid-infrared supercontinuum source, in combination with a 30 m multipass absorption cell, and a scanning grating spectrometer. The output of the spectrometer is demodulated by a digital lock-in amplifier, referenced to the repetition rate of the supercontinuum source. This improved the detection sensitivity of the system by a factor 5, as compared to direct baseband operation.

Sensitive and broadband measurement of dispersion in a cavity using a Fourier transform spectrometer with kHz resolution: erratum.

We correct the values of the group delay dispersion of the cavity mirrors and N, as well as the concentration of CO, obtained from the measurement of the center frequencies of cavity modes using a comb-based Fourier transform spectrometer. The corrected values of group delay dispersion are a factor of 3 higher, which implies that the precision and accuracy of the dispersion measurements is 0.3 fs and 3 fs, respectively.

Time-resolved mid-infrared dual-comb spectroscopy.

Dual-comb spectroscopy can provide broad spectral bandwidth and high spectral resolution in a short acquisition time, enabling time-resolved measurements. Specifically, spectroscopy in the mid-infrared wavelength range is of particular interest, since most of the molecules have their strongest rotational-vibrational transitions in this "fingerprint" region. Here we report time-resolved mid-infrared dual-comb spectroscopy, covering ~300 nm bandwidth around 3.

Mid-infrared supercontinuum-based upconversion detection for trace gas sensing.

Recent advancements of mid-infrared (MIR) supercontinuum light sources have opened up new possibilities in laser-based trace gas sensing. While the supercontinuum sources inherently support wide spectral coverage, the detection of broadband absorption signals with high speed and low cost is traditionally limited by the MIR detector arrays. In this work, we demonstrate that this limitation can be circumvented by upconverting the MIR signal into the near-infrared (NIR) region, where cost-effective silicon-based detector arrays can be utilized to measure broadband absorption.

Mid-infrared dual-comb spectroscopy with absolute frequency calibration using a passive optical reference.

We demonstrate an absolute-frequency-calibrated mid-infrared dual-comb spectrometer by using a reference absorption cell. The source is based on a singly-resonant OPO containing two MgO:PPLN crystals in a common ring cavity, synchronously pumped by two mode-locked Yb-fiber lasers. The repetition-rate of the two pumps are stabilized while their offset frequencies and the OPO cavity length are not actively controlled.

A Broadband Mid-Infrared Trace Gas Sensor Using Supercontinuum Light Source: Applications for Real-Time Quality Control for Fruit Storage.

We present a fully integrated and transportable multi-species trace gas sensor based on a mid-infrared (MIR) supercontinuum light source. The high brightness (surpassing synchrotron) and ultra-broad spectral bandwidth (2-4 μm) of this light source allows simultaneous detection of multiple broadband absorbing gas species. High sensitivity in the sub-ppmv level has been achieved by utilizing an astigmatic multipass cell.

Contralateral eye comparison of the phacoemulsification metrics, patient experience and clinical outcomes in patients undergoing bilateral cataract surgery with two commonly used femtosecond laser systems.

Purpose: The purpose of the study was to compare phacometrics, patient experience factors and clinical outcomes in patients undergoing bilateral laser-assisted cataract surgery using two common femtosecond laser platforms.

Setting: This study was conducted in Beverly Hills Institute of Ophthalmology, Beverly Hills, California, USA.

Study Design: This was a prospective, comparative, contralateral eye study.

Sensitive Spectroscopy of Acetone Using a Widely Tunable External-Cavity Quantum Cascade Laser.

We employed a single-mode, widely tunable (~300 cm) external-cavity quantum cascade laser operating around 8 µm for broadband direct absorption spectroscopy and wavelength modulation spectroscopy where a modulation frequency of 50 kHz was employed with high modulation amplitudes of up to 10 GHz. Using a compact multipass cell, we measured the entire molecular absorption band of acetone at ~7.4 µm with a spectral resolution of ~1 cm.

Laser spectroscopy for breath analysis: towards clinical implementation.

Detection and analysis of volatile compounds in exhaled breath represents an attractive tool for monitoring the metabolic status of a patient and disease diagnosis, since it is non-invasive and fast. Numerous studies have already demonstrated the benefit of breath analysis in clinical settings/applications and encouraged multidisciplinary research to reveal new insights regarding the origins, pathways, and pathophysiological roles of breath components. Many breath analysis methods are currently available to help explore these directions, ranging from mass spectrometry to laser-based spectroscopy and sensor arrays.

Sensitive and broadband measurement of dispersion in a cavity using a Fourier transform spectrometer with kHz resolution.

Optical cavities provide high sensitivity to dispersion since their resonance frequencies depend on the index of refraction. We present a direct, broadband, and accurate measurement of the modes of a high finesse cavity using an optical frequency comb and a mechanical Fourier transform spectrometer with a kHz-level resolution. We characterize 16000 longitudinal cavity modes spanning 16 THz of bandwidth in terms of center frequency, linewidth, and amplitude.

Fourier transform and Vernier spectroscopy using an optical frequency comb at 3-5.4 μm.

We present a versatile mid-infrared frequency comb spectroscopy system based on a doubly resonant optical parametric oscillator tunable in the 3-5.4 μm range and two detection methods: a Fourier transform spectrometer (FTS) and a continuous-filtering Vernier spectrometer (CF-VS). Using the FTS with a multipass cell, we measure high precision broadband absorption spectra of CH at 3.

Analysis of speech-based measures for detecting and monitoring Alzheimer's disease.

Automatic diagnosis of the Alzheimer's disease as well as monitoring of the diagnosed patients can make significant economic impact on societies. We investigated an automatic diagnosis approach through the use of speech based features. As opposed to standard tests, spontaneous conversations are carried and recorded with the subjects.

Noise-immune cavity-enhanced optical frequency comb spectroscopy.

We present a new method of optical frequency comb spectroscopy that combines cavity enhancement with frequency modulation to obtain immunity to laser frequency-to-amplitude noise conversion by the cavity modes and, thus, high absorption sensitivity over a broad spectral range. A frequency comb is locked to a cavity with a free spectral range (FSR) equal to 4/3 times the repetition rate of the laser, and phase-modulated at a frequency equal to the cavity FSR. The transmitted light is analyzed by a Fourier transform spectrometer with a high bandwidth detector.

Cavity-enhanced optical frequency comb spectroscopy of high-temperature H2O in a flame.

We demonstrate near-infrared cavity-enhanced optical frequency comb spectroscopy of water in a premixed methane/air flat flame. The detection system is based on an Er:fiber femtosecond laser, a high finesse optical cavity containing the flame, and a fast-scanning Fourier transform spectrometer (FTS). High absorption sensitivity is obtained by the combination of a high-bandwidth two-point comb-cavity lock and auto-balanced detection in the FTS.

Medical podcasting in Iran; pilot, implementation and attitude evaluation.

Podcasting has become a popular means of transferring knowledge in higher education through making lecture contents available to students at their convenience. Accessing courses on media players provides students with enhanced learning opportunities. Development of teaching methods able to cope with ever-changing nature of medicine is crucial to train the millennium students.