CS Optical Pumping Magnetic Sensor Spectrum Lamp Drive Circuit Design Based on PI Feedback Controller

2014 ◽  
Vol 568-570 ◽  
pp. 473-477 ◽  
Author(s):  
Chao Tan ◽  
Li Fang ◽  
Xue Bai
Keyword(s):  
Emission Intensity ◽  
Optical Pumping ◽  
Spectral Width ◽  
Control Measures ◽  
Experimental Result ◽  
Crystal Oscillator ◽  
Optical Source ◽  
Optical Pump ◽  
Rf Power Amplifier ◽  
Drive Circuit

The optical source is one of the key components for the optical pump magnetic field sensor, its spectral width, stability and emission intensity directly related to the sensitivity of the sensor. The CS Spectral Lamp drive signal source was produced by crystal oscillator and amplified by the power controllable RF power amplifier. For achieving the aim of luminous intensity controllable and more stability, the reference controllable analog PI negative feedback control measures were used in the drive circuit. Contrast experimental result show that: the emission intensity of CS spectrum lamp is more stable and less affected by temperature if using the drive circuit which discussed in this paper.

scholarly journals Study on estimation of creep behaviour of concrete at early age considering temperature effect

2019 ◽  
Vol 289 ◽  
pp. 10010
Author(s):  
Kayo Ohashi ◽  
Jun-ichi Arai ◽  
Toshiaki Mizobuchi
Keyword(s):  
Thermal Stress ◽  
Temperature Effect ◽  
Creep Strain ◽  
Prediction Accuracy ◽  
Creep Behaviour ◽  
Test Method ◽  
Control Measures ◽  
Experimental Result ◽  
Early Age ◽  
And Control

Clarifying the creep behaviour of concrete at early age not only improves the accuracy of temperature stress analysis but also contributes to prediction accuracy and control measures in cracks caused by thermal stress. However, most past researches on creep behaviour were investigated after 28 days. Currently, it is difficult to accurately perceive the creep behaviour of concrete at an early age in the test method of creep which is generally carried out. Therefore, it is necessary to evaluate the creep behaviour of concrete at early age and to establish a convenient test method to estimate the creep behaviour. Therefore, in this study, experiments were carried out for concrete at early age within one week. As the result of the experiments, it was shown that the creep strain is proportional to the load stress of concrete at an early age and the strain of specific creep decreases as the loaded age increases. In addition, based on the experimental results, an estimation equation for creep strain at early age was proposed. Within the scope of this experimental result, it was confirmed that the estimation equation proposed in this study accurately represented the creep behaviour of concrete at early age.

HIGH-POWER OPTICAL SOURCE USING DYE-DOPED POLYMER OPTICAL FIBER

1996 ◽  
Vol 05 (01) ◽  
pp. 73-88 ◽  
Author(s):  
T. YAMAMOTO ◽  
K. FUJII ◽  
A. TAGAYA ◽  
E. NIHEI ◽  
Y. KOIKE ◽  
...  
Keyword(s):  
Optical Fibers ◽  
High Power ◽  
Rhodamine 6G ◽  
Experimental Result ◽  
Polymer Optical Fiber ◽  
Optical Source ◽  
Strong Excitation ◽  
Basic Characteristics ◽  
Polymer Optical Fibers ◽  
Doped Polymer

Basic characteristics of organic-dye doped polymer optical fibers (DPOFs) are demonstrated. The devices contain laser dye, such as Rhodamine 6G (R6G) and Rhodamine B (RB) in the core region. Firstly, amplification characteristics of DPOF amplifiers (PO-FAs) excited by a pulse-operated, doubled Nd:YAG laser are demonstrated, e.g., a 250 mm-length of RB-POFA gives 1 kW (30 dB) of amplified signal at 591 nm. Next, an all solid state system of RB DPOF laser (POFL) is discussed by numerical simulation and the experimental result of high-power amplified spontaneous emission (ASE) by strong excitation of DPOF is shown.

scholarly journals High Sensitivity Optically Pumped Quantum Magnetometer

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Valentina Tiporlini ◽  
Kamal Alameh
Keyword(s):  
Magnetic Field ◽  
Pump Power ◽  
Optimal Design ◽  
Optical Pumping ◽  
High Sensitivity ◽  
Optically Pumped ◽  
Optical Pump ◽  
Operation Temperature ◽  
Quantum Magnetometer ◽  
Sinusoidal Magnetic Field

Quantum magnetometers based on optical pumping can achieve sensitivity as high as what SQUID-based devices can attain. In this paper, we discuss the principle of operation and the optimal design of an optically pumped quantum magnetometer. The ultimate intrinsic sensitivity is calculated showing that optimal performance of the magnetometer is attained with an optical pump power of 20 μW and an operation temperature of 48°C. Results show that the ultimate intrinsic sensitivity of the quantum magnetometer that can be achieved is 327 fT/Hz1/2over a bandwidth of 26 Hz and that this sensitivity drops to 130 pT/Hz1/2in the presence of environmental noise. The quantum magnetometer is shown to be capable of detecting a sinusoidal magnetic field of amplitude as low as 15 pT oscillating at 25 Hz.

Conditions for excited-state Raman and absorption processes during optical pumping

1981 ◽  
Vol 59 (18) ◽  
pp. 2792-2802 ◽  
Author(s):  
B. Halperin ◽  
J. A. Koningstein
Keyword(s):  
Excited State ◽  
Excited States ◽  
Optical Pumping ◽  
Excited Level ◽  
Tunable Laser ◽  
Laser Wavelength ◽  
Photon Flux ◽  
Optical Pump ◽  
Linear Behaviour ◽  
Transmission Studies

A theoretical analysis is presented for conditions of optical pumping of an electronic excited state and the subsequent induction of Raman scattering thereof, using the radiation of a tunable laser with a specific λ for pumping and Raman probing.The analysis shows that the number of excited states created by the optical pump can be estimated as a function of the photon flux from the (non-linear) behaviour of the transmission of the sample at the selected laser wavelength. It is shown that such transmission studies are a prerequisite before attempts are made to record any excited level Raman spectrum.

scholarly journals Xenon lamp control signal and drive circuit design of Er: YAG laser

2021 ◽  
Vol 257 ◽  
pp. 01059
Author(s):  
Chuncheng Chen ◽  
Zhiyi Lu ◽  
Yisong Fan ◽  
Qiang Guo
Keyword(s):  
Circuit Design ◽  
Pulse Width ◽  
Pulse Width Modulation ◽  
Laser Light ◽  
Xenon Lamp ◽  
Frequency Multiplication ◽  
Crystal Oscillator ◽  
Yag Laser ◽  
Drive Circuit ◽  
Stable Laser

When the Er: YAG laser pumped by a xenon lamp emits laser light, the energy, frequency and pulse width of the emitted light are closely related to the discharge of the xenon lamp. This article uses the 8MHz external crystal oscillator that comes with the STM32F4 development board, generates a clock source through frequency division and frequency multiplication, and configures a pulse width modulation (PWM) signal to control the laser. Since the signals sent by the development board are weak signals, it is necessary to design a corresponding drive circuit to amplify the power of the signal. Finally, the voltage of the pulsed xenon lamp is adjustable from 0 to 1400V, and the pulse width is adjustable from 50 to 300μs to achieve stable laser output.

scholarly journals Tunable GaAs metasurfaces for ultrafast image processing

2021 ◽  
Vol 2015 (1) ◽  
pp. 012057
Author(s):  
Viacheslav Iushkov ◽  
Alexander Shorokhov ◽  
Andrey Fedyanin
Keyword(s):  
Image Processing ◽  
Optical Switching ◽  
Optical Pumping ◽  
Relaxation Times ◽  
Optical Computing ◽  
Fused Silica ◽  
Optical Pump ◽  
Pump Probe ◽  
Ultrafast Optical ◽  
Ultrafast Switching

Abstract The design and construction of optical semiconductor metasurfaces for various applications have become an important topic in the last decade. However, most metasurfaces are static; they are optimized for only one exact purpose and typically realize only one operation. In this work, we discuss the basic methods for creating dynamic metasurfaces giving special attention to ultrafast optical switching and provide numerical modeling of metasurfaces made of GaAs material realizing different amplitude-phase profiles under asymmetrical optical pumping. The metasurfaces are composed of semiconductor discs immersed in a fused silica medium. We demonstrate that based on Fourier transform and spatial filtering methods, these structures can be used for image processing and optical computing. Ultrafast switching is achieved by using an optical pump-probe scheme. The characteristic relaxation times between the pumped state and the relaxed state are on the order of several picoseconds.

scholarly journals Superradiant lasing in inhomogeneously broadened ensembles with spatially varying coupling

2021 ◽  
Vol 1 ◽  
pp. 73
Author(s):  
Anna Bychek ◽  
Christoph Hotter ◽  
David Plankensteiner ◽  
Helmut Ritsch
Keyword(s):  
Optical Pumping ◽  
Spectral Width ◽  
Stimulated Emission ◽  
Optical Clock ◽  
Frequency Noise ◽  
Atomic Coherence ◽  
Atom Number ◽  
Large Bandwidth ◽  
Large Numbers ◽  
Spatially Varying

Background: Theoretical studies of superradiant lasing on optical clock transitions predict a superb frequency accuracy and precision closely tied to the bare atomic linewidth. Such a superradiant laser is also robust against cavity fluctuations when the spectral width of the lasing mode is much larger than that of the atomic medium. Recent predictions suggest that this unique feature persists even for a hot and thus strongly broadened ensemble, provided the effective atom number is large enough. Methods: Here we use a second-order cumulant expansion approach to study the power, linewidth and lineshifts of such a superradiant laser as a function of the inhomogeneous width of the ensemble including variations of the spatial atom-field coupling within the resonator. Results: We present conditions on the atom numbers, the pump and coupling strengths required to reach the buildup of collective atomic coherence as well as scaling and limitations for the achievable laser linewidth. Conclusions: We show how sufficiently large numbers of atoms subject to strong optical pumping can induce synchronization of the atomic dipoles over a large bandwidth. This generates collective stimulated emission of light into the cavity mode leading to narrow-band laser emission at the average of the atomic frequency distribution. The linewidth is orders of magnitudes smaller than that of the cavity as well as the inhomogeneous gain broadening and exhibits reduced sensitivity to cavity frequency noise.

Progress in Antimonide-Based Mid-IR Lasers

1999 ◽  
Vol 607 ◽  
Author(s):  
G.W. Turner ◽  
M.J. Manfra ◽  
H.K. Choi ◽  
A.K. Goyal ◽  
S.C. Buchter ◽  
...  
Keyword(s):  
Semiconductor Lasers ◽  
High Performance ◽  
Optical Pumping ◽  
Beam Quality ◽  
Power Conversion ◽  
Active Regions ◽  
High Gain ◽  
Optically Pumped ◽  
Optical Pump ◽  
Peak Output Power

AbstractMid-infrared optically pumped semiconductor lasers (OPSLs) are presently being investigated for a variety of commercial and military applications. Active regions in such optically pumped lasers must meet the dual requirements of high gain and low loss at mid-IR wavelengths, combined with sufficient absorption of the optical pump at shorter wavelengths for efficient power conversion. In this paper we report the successful growth, fabrication, and characterization of high-performance OPSLs that employ novel active regions consisting of combinations of GalnAsSb integrated-absorber layers with type-II GaInSb/InAs quantum well regions. With 1.85-µm optical pumping at 85 K, OPSLs with such active regions have exhibited a peak output power of 2.1 W at 3.9 pm, improved beam quality, power conversion efficiency of ∼8%, and characteristic temperatures of ∼47 K.

scholarly journals Superradiant lasing in inhomogeneously broadened ensembles with spatially varying coupling

2021 ◽  
Vol 1 ◽  
pp. 73
Author(s):  
Anna Bychek ◽  
Christoph Hotter ◽  
David Plankensteiner ◽  
Helmut Ritsch
Keyword(s):  
Optical Pumping ◽  
Spectral Width ◽  
Stimulated Emission ◽  
Optical Clock ◽  
Frequency Noise ◽  
Atomic Coherence ◽  
Atom Number ◽  
Large Bandwidth ◽  
Large Numbers ◽  
Spatially Varying

Background: Theoretical studies of superradiant lasing on optical clock transitions predict a superb frequency accuracy and precision closely tied to the bare atomic linewidth. Such a superradiant laser is also robust against cavity fluctuations when the spectral width of the lasing mode is much larger than that of the atomic medium. Recent predictions suggest that this unique feature persists even for a hot and thus strongly broadened ensemble, provided the effective atom number is large enough. Methods: Here we use a second-order cumulant expansion approach to study the power, linewidth and lineshifts of such a superradiant laser as a function of the inhomogeneous width of the ensemble including variations of the spatial atom-field coupling within the resonator. Results: We present conditions on the atom numbers, the pump and coupling strengths required to reach the buildup of collective atomic coherence as well as scaling and limitations for the achievable laser linewidth. Conclusions: We show how sufficiently large numbers of atoms subject to strong optical pumping can induce synchronization of the atomic dipoles over a large bandwidth. This generates collective stimulated emission of light into the cavity mode leading to narrow-band laser emission at the average of the atomic frequency distribution. The linewidth is orders of magnitudes smaller than that of the cavity as well as the inhomogeneous gain broadening and exhibits reduced sensitivity to cavity frequency noise.

scholarly journals Two-dimensional WSe2 flakes under high power optical excitation

2021 ◽  
Vol 7 (3) ◽  
pp. 109-113
Author(s):  
Kirill A. Brekhov ◽  
Sergey D. Lavrov ◽  
Andrey V. Kudryavtsev ◽  
Nikita A. Ilyin
Keyword(s):  
High Power ◽  
Optical Pumping ◽  
Transition Metal Dichalcogenides ◽  
Experimental Studies ◽  
Optical Excitation ◽  
Optical Response ◽  
Semiconductor Surface ◽  
High Concentration ◽  
Optical Pump ◽  
Thermalization Time

Quasi-2D layers of transition metal dichalcogenides are promising candidates for creating saturable absorbers for pulsed lasers. However, the peculiarities of intense electromagnetic radiation’s influence on such structures have not been thoroughly studied. This paper explores the dynamics of photoexcited carriers in WSe2 flakes through experimental studies. These studies found that WSe2 flakes significantly change their optical properties under the influence of a high-power optical pump, allowed estimating the thermalization time of these structures (about 2 ps), and found that full relaxation takes more than 10 ps. The concentration of carriers in the semiconductor surface layer was estimated to be about 1028 m–3. It was found that standard description models of the optical response based on exciton resonances and absorption by free carriers could not adequately describe the experiments’ results. Thus, for an accurate description of the optical response, it was necessary to consider the effects associated with Coulomb screening that are caused by the high concentration of photo-excited carriers of the optical pumping densities used in this experiment.

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