Multi-stage Amplification Research Articles

Ultra-phase-stable infrared light source at the watt level.

Ultrashort pulses at infrared wavelengths are advantageous when studying light-matter interaction. For the spectral region around 2 µm, multi-stage parametric amplification is the most common method to reach higher pulse energies. Yet it has been a key challenge for such systems to deliver waveform-stable pulses without active stabilization and synchronization systems. Here, we present a different approach for the generation of infrared pulses centered at 1.8 µm with watt-level average power utilizing only a single nonlinear crystal. Our laser system relies on a well-established Yb:YAG thin-disk technology at 1.03 µm wavelength combined with a hybrid two-stage broadening scheme. We show the high-power downconversion process via intra-pulse difference frequency generation, which leads to excellent passive stability of the carrier envelope phase below 20 mrad-comparable to modern oscillators. It also provides simple control over the central wavelength within a broad spectral range. The developed infrared source is employed to generate a multi-octave continuum from 500 nm to 2.5 µm opening the path toward sub-cycle pulse synthesis with extreme waveform stability.

Advances in Atomic Time Scale Imaging with a Fine Intrinsic Spatial Resolution

Atomic time scale imaging, opening a new era for studying dynamics in microcosmos, is presently attracting immense research interest on the global level due to its powerful ability. On the atom level, physics, chemistry, and biology are identical for researching atom motion and atomic state change. The light possesses twoness, the information carrier and the research resource. The most fundamental principle of this imaging is that light records the event-modulated light field by itself, so-called all-optical imaging. This paper can answer what is the essential standard to develop and evaluate atomic time scale imaging, what is the optimal imaging system, and what are the typical techniques to implement this imaging, up to now. At present, the best record in the experiment, made by multistage optical parametric amplification (MOPA), is realizing 50-fs resolved optical imaging with a spatial resolution of ~83 lp/mm at an effective framing rate of 15 × 10 12 fps for recording an ultrafast optical lattice with its rotating speed up to 13.5 × 10 12 rad/s.

Development of a high-voltage radio frequency power supply for quadrupole mass spectrometers with a wide dynamic measurement range

The core component of a quadrupole mass spectrometer is the quadrupole mass filter, serving a crucial role in ion analysis. It operates by applying two sets of high-voltage, high-frequency signals with equal amplitude and opposing phases through the radio frequency power supply, capitalizing on variations in the electric field and differences in mass-to-charge ratios to separate incoming ions. This study leverages direct digital frequency synthesis technology and multi-stage voltage amplification techniques to design a tailored radio frequency power supply for quadrupole mass spectrometers with a broad mass range. Practical testing demonstrates that this power supply generates radio frequency high-voltage signals with a peak-to-peak voltage ranging from 2.210 V to 4.220 kV at a resonant frequency of 1.240 MHz, facilitating the separation of ions with distinct m/z values. Furthermore, the radio frequency power supply is integrated into a Self-developed quadrupole mass spectrometer, enabling an assessment of the mass range, resolution, stability of the spectrometer. The results of these assessments confirm that the developed power supply accommodates scanning of m/z value ions in the range of 1 to 1067 while maintaining an absolute resolution of less than m/z = 1 units and an instrument stability of 2.00% over four hours.and keywords.

Design of a two-stage compliant asymmetric piezoelectrically actuated microgripper with parasitic motion compensation

The parasitic motion of microgripper jaws affect clamping accuracy. The parallelogram mechanism (PM) is often used as the last-stage of the multi-stage amplification mechanisms (AMs) because of its parallel clamping characteristics. However, the PM traditionally used in multi-stage AMs is asymmetrically stressed, which will affect its parallel clamping accuracy. Based on this, a PM with symmetrical forces is designed. The paper addresses the issue of parasitic motion in microgripper jaws and its impact on clamping accuracy, which is a relevant concern in micro-scale manipulation systems. The design of a symmetrically stressed PM for use in a two-stage asymmetric microgripper is a novel contribution to the field. Based on the minimum potential energy principle and the Castigliano's second theorem, the mechanical modeling of the mechanism's parasitic displacement, magnification and parallel clamping accuracy is carried out. Comparing the mechanical model, finite element analysis (FEA) and experimental measurement results, the values given by the three different methods are close. The method given in this paper to improve the clamping accuracy of the mechanism is also applicable to similar compliant mechanisms.

DNAzyme-driven bipedal DNA walker and catalytic hairpin assembly multistage signal amplified electrochemical biosensor based on porous AuNPs@Zr-MOF for detection of Pb2+

As a highly toxic and refractory heavy metal contaminant, Pb2+ seriously endangers human health. The problems of low sensitivity and high cost of signal labeling widely exist in common electrochemical biosensors. Herein, a Pb2+ electrochemical biosensor was constructed using a DNAzyme-driven bipedal DNA Walker and catalytic hairpin assembly as the multistage signal amplification strategy. Compared with Zr-MOF, AuNPs@Zr-MOF has a larger porosity and specific surface area, which can effectively load MB to amplify the current signal. Pb2+ can trigger a dual signal amplification reaction to gradually accumulate the signal of methylene blue/gold nanoparticle @ zirconium-based metal organic frameworks (MB/AuNPs@Zr-MOF) on the electrode. The ingeniously designed sensing strategy realized the analysis of Pb2+ with a wide linear range from 0.05 to 1000 nmol/L and a lower limit of detection (LOD) of 4.65 pmol/L. In addition, the sensor has strong anti-interference ability and can accurately detect Pb2+ in various food samples.

Integrated Encapsulation and Implementation of a Linear-Mode APD Detector for Single-Pixel Imaging Lidar

Single-pixel imaging lidar is a novel technology that leverages single-pixel detectors without spatial resolution and spatial light modulators to capture images by reconstruction. This technique has potential imaging capability in non-visible wavelengths compared with surface array detectors. An avalanche photodiode (APD) is a device in which the internal photoelectric effect and the avalanche multiplication effect are exploited to detect and amplify optical signals. An encapsulated APD detector, with an APD device as the core, is the preferred photodetector for lidar due to its high quantum efficiency in the near-infrared waveband. However, research into APD detectors in China is still in the exploratory period, when most of the work focuses on theoretical analysis and experimental verification. This is a far cry from foreign research levels in key technologies, and the required near-infrared APD detectors with high sensitivity and low noise have to be imported at a high price. In this present study, an encapsulated APD detector was designed in a linear mode by integrating a bare APD tube, a bias power circuit, a temperature control circuit and a signal processing circuit, and the corresponding theoretical analysis, circuit design, circuit simulation and experimental tests were carried out. Then, the APD detector was applied in the single-pixel imaging lidar system. The study showed that the bias power circuit could provide the APD with an operating voltage of DC 1.6 V to 300 V and a ripple voltage of less than 4.2 mV. Not only that, the temperature control circuit quickly changed the operating state of the Thermo Electric Cooler (TEC) to stabilize the ambient temperature of the APD and maintain it at 25 ± 0.3 °C within 5 h. The signal processing circuit was designed with a multi-stage amplification cascade structure, effectively raising the gain of signal amplification. By comparison, the trial also suggested that the encapsulated APD detector and the commercial Licel detector had a good agreement on the scattered signal, such as a repetition rate and pulse width response under the same lidar environment. Therefore, target objects in real atmospheric environments could be imaged by applying the encapsulated APD detector to the near-infrared single-pixel imaging lidar system.

Design and mechanical modeling of high-magnification and low-parasitic displacement microgripper with three-stage displacement amplification

The common point of multi-stage displacement amplification mechanisms (DAMs) is that the output end of the upper-stage DAM is connected to the input end of the next-stage DAM. Therefore, the input stiffness of the next-stage DAM will have an impedance effect on the output displacement of the upper-stage DAM. Based on this, the paper introduces a three-stage amplification microgripper, which is driven by a piezoelectric actuator. The three-stage DAM is composed of a compound rhombic mechanism, a bridge mechanism and two parallelogram mechanisms. Based on Cartesian second theorem and flexure beam theory, the mechanism's displacement magnification model, input force and output force relationship model, force-displacement relationship model, input stiffness model and parasitic displacement compensation model are established. The correctness of mechanical modeling is verified by simulation analysis and experiments. The results show that the mechanical model has high prediction accuracy.

Investigations of the High-Power, Single-Frequency, Sub-Microseconds, 1548-nm Fiber Laser Based on the Optical Pulse Modulation

High-power, single-frequency lasers are important in the applications of coherent optical communication, Doppler wind lidar, and remote sensing. Here, a 10-kHz, 353-μJ, single-frequency, 574-ns, 1548-nm fiber laser system was demonstrated based on the optical pulse modulation. The 1548-nm, single-frequency seed laser with the linewidth of 1.25 kHz was modulated by two acousto-optic modulators (AOMs) into a 10-kHz pulsed laser. Two cascaded fiber amplifiers were spliced after the AOMs to scale up the pulse energy. The amplified spontaneous emission (ASE) was inhibited by the multistage amplification construction and the optical bandpass filters. A customized pulse profile was proposed to pre-compensate the temporal modulation and inhibit the stimulated Brillouin scattering (SBS) effect. The pulse duration of the amplified single-frequency pulse was 574 ns, with the peak power of 753 W. A numerical model was also built for investigating the dynamic of the interaction process inside the power amplifier. The simulated results indicate the maximum output power of the 10-kHz, customized single-frequency laser can be 3.984 W with a pulse duration of 381 ns.

A high affinity borate ester bond molecularly imprinted sensor based on multistage amplification of UCNPs-NH2 electrochemiluminescence with bifunctional synergistic accelerator CeO2 @N-MC for ultrasensitive detection of ribavirin

A molecularly imprinted electrochemiluminescence sensor (MIECLS) was constructed to detect ribavirin (RBV) using a bifunctional synergistic accelerator as an enhancement tool combined with boronic acid affinity molecularly imprinted polymer (MIP). Amino-functionalized upconversion nanoparticles (UCNPs-NH2) generated an electrochemiluminescence signal and promoted the production of sulfate anion radicals (SO4−•), achieving self-enhancement. Nanosized ceria (CeO2) was spatially matched with the pores of nitrogen-doped mesoporous carbon (N-MC) to form CeO2@N-MC. N-MC not only prevented CeO2 from self-aggregation but also provided electron transfer channels. The doping of CeO2 provided cyclic catalytic sites (Ce3+/Ce4+) that promoted SO4−• generation, shortening the redox reaction distance. The high-speed electron transfer center and high-efficiency cycle catalytic center enabled the bifunctional synergistic effect of CeO2@N-MC, thus greatly improving the electrochemiluminescence signal. Simultaneously, MIP formed by the combination of covalent and noncovalent actions was grafted onto the electrochemiluminescence sensing interface to construct MIECLS. The detection range and the limit of detection (LOD) were found to be 1 × 10−9–5 × 10−6 mol L−1 and 2.27 × 10−10 mol L−1, respectively. MIECLS was used for the detection of RBV in real samples with the recoveries of 86.12–95.90 %, which was consistent with the HPLC results.

Beam-type metastructure with X-shape inertial amplification mechanisms for vibration suppression

A new type of beam-type metastructure periodically attaching single- or multi-stage X-shape inertial amplification (XIA) mechanisms is designed to realize efficient elastic wave attenuation and wide bandgaps benefiting the vibration suppression. Band structures of the unit cell and vibration response of the finite beam are validated numerically and experimentally. Numerical results show that compared with the triangular inertial amplification beams with the same added masses, XIA mechanisms generate wider bandgaps with higher attenuation constants at the same frequency band, for the same inertia amplification (IA) angle or same installation space. Parametric studies reveal that XIA mechanisms lead to the coupling effect of transverse wave and longitudinal wave, and induce a newly emerging bandgap. Moreover, the variations of IA angle, amplification ratio and number of stages apply basically similar effects on band structures, except the IA span. Finally, in order to explore practical applications on vibration suppression of XIA mechanisms, two schemes of multiple mechanisms in a unit cell and the hybrid unit cell are investigated. The proposed designs of XIA mechanisms have the potential to improve the capability of vibration suppression of the structures in engineering practices.

Two types of morphing wing designs based on multistage displacement amplification mechanisms

Two types of morphing wing designs based on multistage displacement amplification mechanisms

Long-distance modal power equalization with hybrid pumped FM-EDFA

In a few-mode fiber-based mode division multiplexing system, the different modes as distinct channels suffer from discrepant mode-dependent loss, leading to an intensive channel power imbalance and large bit error. The few-mode erbium-doped fiber amplifier (FM-EDFA) enables mode power regulation to ensure high-quality long-distance transmission. In this paper, we propose an FM-EDFA for long-haul equalization with a core and cladding hybrid pump structure. The particle swarm optimization is applied to determine the multilayered erbium ions doping profile. Based on the profile, targeted compensation for high-order modes with high loss is realized to mitigate the power difference in long-distance transmission. Compared with the single pump selection, the differential modal gain reduces from 6.553 dB to 1.239 dB in the hybrid pump with a 1000 km multistage amplification and transmission. We provide new ideas for loss compensation and power balance in long-distance transmission. This method has the ability of dynamic power adjustment while keeping the design simple.

Amplification and Transmission System With Matching Multi-Layer Ion-Doped FM-EDFA

System stability and robustness are highly desired in a mode division multiplexing (MDM) transmission system. The matching of the active fiber and transmission FMF effectively reduces the transmission impairments and is conducive to transmission stability. In this paper, we proposed and fabricated a well-matched triple-layered-core few-mode erbium-doped fiber (FM-EDF) for low differential modal gain (DMG) with multilayer ions doping adjustment. Based on the fabricated FM-EDF, the amplifier is constructed experimentally. By a simple LP <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">01</sub> pump mode, the modal gains are higher than 24 dB, and meanwhile, the DMG of 1.6 dB is obtained. The compatibility between the FM-EDF and the passive transmission FMF is verified in an MDM transmission system with a matching degree higher than 83%. Results show that after long-haul FMF transmission and single-stage amplification, the difference in the output signal power is lower than 1.8 dB at the receiver. The fabricated FM-EDF is beneficial for practical MDM systems with high mode stability, excellent fiber linkage integration, and signal channel equalization, which shows much potential for long-haul MDM transmission and multistage amplification.

Chemiluminescence resonance energy transfer-based multistage nucleic acid amplification circuits for MiRNA detection with low background.

Chemiluminescence resonance energy transfer (CRET)-based assays have shown great potential in biosensing due to their negligible background autofluorescence, yet are still limited by their low sensitivity and short half-life luminescence. Herein, a multistage CRET-based DNA circuit was constructed with amplified luminescence signals for accurate miRNA detection and fixed reactive oxygen species (ROS) signals for cell imaging. The DNA circuit is designed through an ingenious programmable catalytic hairpin assembly (CHA), hybridization chain reaction (HCR), and the use of DNAzyme to realize target-triggered precise regulation of distance between the donor and acceptor for CRET-mediated excitation of photosensitizers. In detail, the analyte catalyzes the hybridization of CHA reactants, which leads to the assembly of multiple HCR-mediated DNAzyme nanowires. Subsequently, DNAzymes catalyze the oxidation of luminol by H2O2, and the adjacent photosensitizer chlorin e6 (Ce6) anchored on the DNA nanostructure is stimulated by the CRET process, resulting in the amplified long-wavelength luminescence and the generation of single oxygen signals through further energy transfer to oxygen. The biomarker miRNA can be detected with great sensitivity by integrating the recognition module into a universal platform. Furthermore, the DNA circuit enables CRET-mediated intracellular miRNA imaging, by detecting singlet oxygen signals through a ROS probe. The significant amplification effect is attributed to the robust multiple recognition of the target and the guaranteed transduction of the CRET signal through programmable engineering of DNA nanostructures. The CRET-based DNA circuit achieves amplified long-wavelength luminescence for accurate miRNA detection with low background and ROS-mediated signal fixation for cell imaging, making it a promising candidate for early diagnosis and theranostics.

Magnetostrictive Vibration Harvester with a Multistage Amplifier and Its Application in Human Walking Energy Harvesting

In this paper, as a theoretical basis, a foot vibration harvester with a finite support mechanism is proposed based on the Villari effect of magnetostrictive materials and Faraday’s law of electromagnetic induction, where a rod-shaped Terfenol-D is used as a core element for energy conversion, and a multi-stage force amplification mechanism is used as a core mechanical structure. The purpose of the amplification mechanism is to amplify the input force provided to the Terfenol-D rod and increase the output electric power. Moreover, the amplification mechanism is designed based on the bridge amplification structure, microlever amplification structure, and wedge amplification mechanism. A mathematical model of the amplification mechanism was developed using the force analysis and unit stiffness matrix methods, and the size and structure were designed and optimized. The performed simulations yielded an output force amplification ratio of 18.04. Based on the optimization results, a prototype was fabricated, and experiments were conducted. Specifically, experiments on the effect of the bias magnetic field on the harvester’s harvesting capability were performed, and the operating characteristics were tested for one complete cycle. Moreover, the effects of the amplification mechanism and vibration harvester were tested for practical applications. The peak output voltage of the harvester was 397.5[Formula: see text]mV under 100 N excitation, and the output electrical power on a resistive load could reach 3.33[Formula: see text]mW. In the application of the human walking process, the voltage could reach a maximum value of 387.3[Formula: see text]mV. The results of the study initially prove that the designed vibration harvester can stably collect human walking vibration.

LD end-pumped Er,Pr:GYSGG single crystal fiber laser as a potential mid-infrared seed source applied in radiation environment

We demonstrate the influence of gamma-ray irradiation on the propagation loss and laser performance of an Er,Pr:GYSGG single crystal fiber (SCF). The size of SCF is Φ 0.75 mm × 70 mm and the diameter fluctuation is less than ±3.5%. The propagation loss coefficients of the samples are 0.07 and 0.09 dB cm−1 before and after irradiation, respectively, which is almost unaffected. The maximum output powers of 197 and 192 mW on the SCFs before and after irradiation are obtained under a 969 nm laser diode (LD) end-pumping, corresponding to the slope efficiencies of 8.1% and 7.9%, respectively. A very good beam quality factor Mx2/My2 of 1.11/1.13 is achieved. These results imply that the Er,Pr:GYSGG SCF laser can be used as a potential seed source for mid-infrared (MIR) multi-stage amplification laser apparatus applied in radiation environment.

2.3 W, Linearly-Polarized Superfluorescent Generation From a Polarization-Maintaining Er3+-Doped Fluoride Fiber Amplifier Around 2.8 μm

We present a high-power, polarization-maintaining (PM) Er <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3+</sup> -doped fluoride fiber amplifier, which enables watt- level, linearly-polarized (LP) superfluorescent outputs around 2.8 μm by using a non-PM Er <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3+</sup> -doped fluoride fiber superfluorescent source (FSS) after polarization controlling as the seed. Based on an optimized scheme, the gained superfluorescent signal with a 20 dB bandwidth of 95 nm (2710∼2805 nm) can yield a maximum power of 2.32 W and a polarization extinction ratio (PER) of up to ∼23.6 dB. To our knowledge, this is the first demonstration of a mid-infrared (mid-IR) PM fiber amplifier, and the power also represents, until now, the highest level from a FSS in the mid-IR. Further power scaling is only limited by the seed power, and can be anticipated by boosting seed power or/and adopting multi-stage amplification. This work provides an alternative way for high-power, LP, mid-IR FSS, enabling a range of real-world applications.

Magnetostrictive biomechanical energy harvester with a hybrid force amplifier

Vibrating energy harvesters, capable of converting mechanical energy into electrical energy, have attracted unprecedented interest in both academia and industry because of their great potential for harvesting energy induced by human activity and energy around the body, and to drive low-power wearable biosensors and electronics, micro-robots, and implantable biomedical devices. In this paper, based on the magnetostrictive inverse effect, we propose a magnetostrictive vibration harvester using Terfenol-D, which generates electrical energy when subjected to human movement. A hybrid force amplification frame is integrated in this harvester to amplify weak biological movements. The detailed mathematical model of the multi-stage force amplification process is established, the hybrid force amplifier is also designed in detail, and its structural dimensions are optimized. The position and form of the bias magnetic field arrangement based on the Terfenol-D harvester is systematically analyzed. The experiment shows that 4.13 V peak voltage and 426.4 mW peak power are generated when the harvester is fully compressed. The output power is 213.16 mW and 371.43 mW at an average acceleration of 2.5 g for slow walking and 4 g for jogging, respectively. The results of this study suggest that the combination of rod Terfenol-D and force amplification mechanisms can be used to design bio-vibrational energy harvester with excellent performance, which is especially suitable for self-powered wearable electronic devices.

Metal-organic framework-enabled surface state passivation integrating with single-nuclease-propelled multistage amplification for ultrasensitive lab-on-paper photoelectrochemical biosensing

The surface states and photoinduced corrosion in the photoelectrode can severely reduce the photocurrent signal and stability of photoelectrochemical (PEC) sensor, which imposes a great challenge on the improvement of analytical performance. Herein, metal–organic framework (MOF)-enabled surface passivation strategy is proposed to passivate surface states, suppress photocorrosion and facilitate interfacial charge transport. In the concrete, zeolitic imidazolate framework-8 (ZIF-8), which serves as the passivation layer, is in-situ assembled on the surface of paper-based ZnO nanorods (NRs) array to restrain the charge trapping at the surface states and keep ZnO NRs from photocorrosion, thereby substantially enhancing the photocurrent signal and durability. Moreover, the unique single-nuclease-propelled multistage amplification (SNMA) and triple-helix molecular switch (THMS)-conformation-transition-mediated signal quenching strategies are also designed to further improve the sensitivity. The SNMA process can convert target microRNA-141 into quadruple amount of useful output DNA strands (trigger DNA) in one duplex-specific nuclease (DSN) cleavage cycle assisted by succedent DSN cleavage of DNA duplexes, guaranteeing a higher target amplification efficiency. Subsequently, the THMS structure which anchors double amount of signal enhancers to the photoelectrode surface can be disassembled by the resulted trigger DNA, therefore achieving powerful signal amplification. Profiting from the MOF-enabled surface state passivation and elegantly designed signal amplification strategies, the ultrasensitive detection of microRNA-141 is realized with a liner range from 0.2 fM to 2 nM and detection limit of 72 aM, which provides a promising paradigm for developing high-performance lab-on-paper PEC biosensing platform.

Multistage nucleic acid amplification induced nano-aggregation for 3D hotspots-improved SERS detection of circulating miRNAs

Circulating miRNAs in the blood can regulate disease development and thus indicate disease states via their various expression levels. For these reasons, circulating miRNAs constitute useful biomarkers, and an approach to the accurate detection of circulating miRNAs is attractive in the diagnosis and treatment of diseases. However, methods for clinical detecting of circulating miRNA that take both sensitivity and practicality into account are still needed. Therefore, we aimed herein to solve some inherent problems in the actual detection using a robust surface-enhanced Raman scattering (SERS) platform with integrated nucleic acid amplification and nanoparticle aggregation to construct 3D hotspots for improving performance of analyzing circulating miRNAs. After target recognition and initial signal amplification by DNAzyme, we observed that release triggered an open hairpin DNA on gold nanoparticles (AuNPs), which then promote AuNP aggregation, causing the accumulation of a large number of hotspots in three-dimention. The SERS biosensor achieved a better performance than the sandwich-type separation detection, with a low detection limit (0.37 fM) and a broad linear range (1 fM–10 nM) in liquids. This SERS platform can be used as a powerful tool for the detection of circulating miRNAs, and it can be used to improve the sensitivity and accuracy of various clinical-disease diagnoses.Graphical