共查询到20条相似文献,搜索用时 859 毫秒
1.
M. A. Bryushinin V. V. Kulikov E. V. Mokrushina E. N. Mokhov A. A. Petrov I. A. Sokolov 《Physics of the Solid State》2014,56(10):1939-1946
The effect of the non-steady-state photoelectromotive force in 6H-SiC crystals irradiated by reactor neutrons has been investigated experimentally. The dependences of the signal amplitude on the phase modulation frequency, spatial frequency, light intensity, and amplitude of an external alternating-current (ac) electric field have been analyzed. The unusual frequency dependence of the signal has been explained in terms of the two-level semiconductor model taking into account shallow traps. The photoelectric parameters of the crystals have been determined for the light wavelength λ = 532 nm. 相似文献
2.
M. A. Bryushinin V. V. Kulikov Yu. A. Kumzerov E. V. Mokrushina A. A. Petrov I. A. Sokolov 《Physics of the Solid State》2014,56(8):1644-1653
The non-steady-state photoelectromotive force effect was experimentally studied in a semiconductor nanowire array, i.e., in a composite representing selenium in a chrysotile asbestos matrix. The sample was exposed to an oscillating interference pattern, and the material response was measured as an alternating electric current. The experiments were performed for two geometries in which the excited photocurrent was parallel or perpendicular to nanowires. The dependences of the signal amplitude on the phase modulation frequency, spatial frequency, light polarization, and temperature were obtained. The photoelectric parameters of the material were determined for the light wavelength λ = 633 nm. The effect was theoretically analyzed for the semiconductor model with shallow traps, which allowed the explanation of the observed increase in the signal amplitude in the presence of additional phase modulation. 相似文献
3.
We demonstrate a scheme for displacement measurement by use of the photoelectromotive force effect and a frequency-modulated laser diode. The measurement range can be adjusted by a change in the depth of frequency modulation, thus making the measurement method both simple and versatile. 相似文献
4.
A giant photovoltaic effect was revealed in silicon-type photoelectronic converters (solar cells) coated with specific antireflecting
films developed by our research group. More specifically, it was found that the ratio of photoconversion efficiency for a
solar cell with such an antireflective film on its surface to the efficiency for a solar cell without the film equals a second
power of relation of photoelectromotive force of a converter with the film to the photoelectromotive force of a converter
without the film. The film comprises an antireflecting coating that is high-efficient in the wavelength range of 450 to 1000
nm and that is synthesized on the basis of novel nanomaterials that provide the quasi-zero average complex refractive index
of nanocomposite film. 相似文献
5.
M. A. Bryushinin 《Technical Physics》2004,49(8):1016-1020
A nonlinear interaction of moving space-charge and photoconductivity gratings is experimentally investigated. In the presence
of a dc electric field, a crystal is irradiated with an oscillating interference pattern with a spatial frequency K and an oscillation frequency ω. An ac electric field with a frequency \gM is also applied to the sample. At certain frequencies
ω and \gM, the crystal exhibits two types of interacting oscillations: the space-charge grating moving with velocity |ω−Ω|/K and the photoconductivity grating moving with velocity −ω/K. The effect is studied using the method of the nonstationary photoelectromotive force in a photorefractive Bi12SiO20 crystal. 相似文献
6.
《中国物理快报》2016,(11)
In the backward propagation of acoustic waves,the direction of phase velocity is anti-parallel to that of group velocity.We propose a scheme to manipulate the backward propagation using a periodical structure.The dynamic backward propagation process is further experimentally observed.It is demonstrated that the oblique incident plane wave moves backward when it travels through the periodical structure and the backward shift can be controlled within a certain range. 相似文献
7.
We investigate the nonlinear optical interaction through a periodic waveguide structure consisting of two alternating segments with different linear and nonlinear optical properties. A coupled equation system has been used to calculate the intensity of fundamental and second harmonic waves and the phase shift of the fundamental. The model has been experimentally tested with good results, but the effect of the phase shift has not been considered. Comparison with the quasi-phase match (QPM) technique has been presented. The novel features introduced by alternating segments with different linear and nonlinear optical properties have been discussed. The model shows a more flexible approach, which can be used in designing optical components based on coherent nonlinear interaction. Applications are straightforward for frequency doubler and all-optical switch. 相似文献
8.
V. A. Ivanov I. A. Viktorov V. F. Gremenok E. P. Zaretskaya I. V. Bodnar’ 《Journal of Applied Spectroscopy》1997,64(1):136-139
Spectra of the photoelectromotive force of p-CuInSe2 single crystals obtained by directional crystallization of a stoichiometric-composition melt in an upright ampoule have been
investigated by the method of phase-sensitive detection. A difference in the phase shifts between the exciting light and the
arising photoelectromotive force in the extrinsic (impurity) and intrinsic regions of optical absorption is determined. The
lifetime in the region of optical self-absorption is found to equal τ=15·10−6 at T=77 K.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 1, pp. 129–131, January–February, 1997. 相似文献
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11.
《Current Applied Physics》2003,3(5):449-455
In the design of the split-type free displacer Stirling cryocooler, the motion of the displacer is very important to the cooling capacity, which depends on the working gas pressure, the swept volume in the compression space and the expansion space, the operating frequency, the phase shift between the piston and the displacer, and other factors. This study describes design and manufacture of the Stirling cryocooler actuated by the electric force of the dual linear motor. The cool-down characteristics of the cold end with laser displacement sensor in the expander of the Stirling cryocooler were evaluated. The charging pressure was 15 kgf/cm2 and the operating frequency was 50 Hz. The input power and the lowest temperature were about 32 W and 67 K, respectively. The displacement of the piston was measured by LVDTs (linear variable differential transformers), the displacement of the displacer was measured by the laser optic method, and the phase shift between piston and displacer was investigated. As the peak-to-peak pressure of the compressor increased, the peak-to-peak displacement of the displacer increased. The peak-to-peak displacement of the displacer increased in the range of 0–64.5 Hz (the resonant frequency of the displacer), but decreased steeply when the operating frequency was higher than the resonant frequency. Finally, when the phase shift between the displacements of the piston and the displacer was 45°, the operating frequency was optimum and was decided by the resonant frequency of the expander, the mass and cross-sectional area of the displacer and the constants of friction and flow resistance. 相似文献
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13.
Relationship measurement between ac-Stark shift of ~(40)Ca~+ clock transition and laser polarization direction 下载免费PDF全文
Ac-Stark shift of atom levels is caused by an ac-electromagnetic field. As an electromagnetic wave, laser light does induce ac-Stark shift. It is proved experimentally that if the light is linearly polarized, the dynamic polarizability changes with polarization direction. The polarization direction of the linearly-polarized laser is tuned by 720?, and the ac-Stark shifts of the 4S_(1/2),m=±1/2→3D_(5/2,m=±1/2) clock transitions in ~(40)Ca~+ are measured in steps of 10?. The frequency shifts change with laser polarization in a periodical manner and have values opposite to each other. 相似文献
14.
Compensation of dispersion-induced power fading for highly linear radio-over-fiber link using carrier phase-shifted double sideband modulation 总被引:2,自引:0,他引:2
A carrier phase-shifted (CPS) double sideband (DSB) modulation technique in radio-over-fiber (RoF) system is proposed and experimentally demonstrated. By tuning the biases in a single-drive dual parallel Mach-Zehnder modulator (SD-DPMZM), the optical carrier in the DSB spectrum acquires additional phase shift. The transmittance response of a dispersive RoF link is thus being controlled and shifted in the frequency domain. Experiments successfully turned the maximum transmission frequency to 10?GHz and 15?GHz for both 25 and 39?km fiber links. This is also a highly linear scheme, of which a spurious-free dynamic range (SFDR) of 111.3?dB·Hz2/3 is experimentally obtained. 相似文献
15.
An experimental method for measurement of subpixel microdisplacements of speckle structure based on the parameters of the linear phase shift in the field of the complex spatial spectrum of the displaced structure is proposed and experimentally implemented. The phase shift is determined when a phase shift of spectrum is numerically added and the correlation analysis of the resulting linear phase shift in the spatial spectrum of specklegrams is performed. The method provides additional possibilities in the measurements using digital speckle photography when the period of interference fringes formed in the total spatial spectrum of specklegrams is significantly greater than the spectral width.
相似文献16.
利用平板波导法研究了不同入射角度下周期排列开口谐振环负磁导率材料、周期排列金属杆负介电常数材料以及左手材料微波反射特性,并利用劈尖法研究了左手材料的负折射特性.实验结果表明:负磁导率材料反射率曲线形成反射峰,其对应的反射峰频率与材料的谐振频率一致;负介电常数材料反射率接近0dB;左手材料出现单个反射较小的反射峰,其峰值反射率随入射角度的增大而变大,即反射能力增强,且反射峰与透射峰有相对频移.劈尖法测量还表明,左手材料在9800MHz频率附近出现负折射现象,其折射率n为-0.796.
关键词:
左手材料
反射
负折射率 相似文献
17.
多孔硅(PS)的可见光致发光的发现[1],引起人们对PS的光电特性及其在光电器件上应用可能性的广泛探索.已报道用PS制成发出可见光的电致发光器件[2]及高灵敏的光探测器件[3].本文将报道PS层与金属接触,光照时能出现很强的光生伏特效应,利用这一特性有可能制成高效的光电转换器件. 相似文献
18.
提出了一种激光多普勒频移测量方法, 此方法利用正弦相位调制使信号光在原频率成分基础上产生正负一阶边带, 再由Fabry-Perot干涉仪对调制光振幅和相位进行调整, 使其产生固定频率的拍频信号, 利用此拍频信号的振幅随频率变化而变化的性质来进行多普勒频移测量. 通过理论分析证明该方法具有很高的测量精度, 加工装调难度不大, 兼顾了普通相干与非相干探测方法的优势. 另外通过实验证明该方法的正确性与可行性, 并通过与普通非相干方式比较发现该方法在测量精度上可以提高 约1个数量级.
关键词:
多普勒频移
相位调制
Fabry-Perot干涉仪
拍频 相似文献
19.
《Laser \u0026amp; Photonics Reviews》2017,11(6)
The well‐known linear Doppler effect arises from the linear motion between source and observer, while the less well‐known rotational Doppler effect arises from the rotational motion. Here, we present both theories and experiments illustrating the relationship between the rotational and linear Doppler effects. A spiral phaseplate is used to generate a light beam carrying orbital angular momentum and the frequency shift is measured arising from its rotational and/or linear motion. By considering either the motion‐induced time‐evolving phase or the momentum and energy conservation in light‐matter interactions, we derive the rotational Doppler shift, linear Doppler shift, and overall Doppler shift associated with rotational and linear motions. We demonstrate the relationship between rotational and linear Doppler shifts, either of which can be derived from the other effect, thereby illustrating their shared origin. Moreover, the close relationship between rotational and linear Doppler effects is also deduced for a more general moving rough surface. 相似文献