Photoelectric device and microsystem
2019, 48(6): 620001.
doi: 10.3788/IRLA201948.0620001
As the quantitative precision of remote sensing information is higher and higher,the polarization correction factor attracts more attention. Therefore, the research on the polarization feature of remote sensors and obtaining normalized Muller elements is necessary, which play an important role in the quantitative research of remote sensing information and polarization correction. However, the polarization sensitivity cannot reflect the polarization feature, which is the comprehensive reflection of polarization response. The analytic method of normalized Muller elements was studied by Fourier series fitting, and the polarization response of remote sensors was obtained. And then the normalized Muller elements m2, m3 were calculated by the polarization response, based on Fourier series fitting. The normalized Muller elements at different Fourier orders were analyzed, and the relative deviation was better than 0.12%. Finally the test error of normalized Muller elements was analyzed, which was better than 0.96%, and the research has further application for the normalized Mueller elements of the remote sensors.
2019, 48(6): 620002.
doi: 10.3788/IRLA201948.0620002
As a new type of spatial light modulator, Digital Micromirror Device(DMD) has the advantages of high resolution, low production cost and high processing efficiency. It is very flexible to use, so the laboratory built a near infrared spectrometer based on DMD. First, the basic working principle of DMD near-infrared spectrometer was introduced. Secondly, the wavelength of spectrometer was calibrated, a method based on the correlation coefficient of the same sample absorbance curve was proposed to normalize the inter-wavelength difference, so that the inter-station difference of the wavelength was theoretically less than 0.1 nm, which meet the requirements when the model was transferred. The selection criteria of different coding templates for DMD near-infrared spectrometer were obtained by comparing the noise and signal-to-noise ratio test under strong light and weak light conditions:the scanning method was better than the Hadamard method under strong light conditions, the opposite in weak light. Finally, the actual sample gasoline and diesel were tested by the spectrometer, and the test results showed that the spectrometer performance was stable. The near-infrared spectrometer based on DMD has a detection wavelength range of 1 330 to 2 500 nm, absorbance deviation is less than 0.000 4 AU.
2019, 48(5): 520001.
doi: 10.3788/IRLA201948.0520001
Phase shifter is one of basic integrated optical structures, and wavelength dependence of its phase shift value determines operation wavelength range of devices. An experimental investigation was conducted on silica-based integrated optical phase shifter designed respectively in two different regimes, length difference regime (LDR) and refractive index difference regime (RIDR), aiming at wavelength dependence of phase shifter. Phase shifters of 180 were respectively designed in the two regimes and inserted between two interference arms of Mach-Zehnder interferometers(MZI). Based on these two structures, a quantitative comparison on phase shift wavelength dependence was made by measuring wavelength dependence of MZI insertion loss. Experimental results show that the operation wavelength range of phase shifters designed in the RIDR was approximately 1.8-1.9 times that designed in the LDR. Analysis shows that the experimental results are in agreement with the theoretical calculations, which proves that phase shifter designed in RIDR possesses weaker wavelength dependence and thus wider operation wavelength range.
2019, 48(5): 520002.
doi: 10.3788/IRLA201948.0520002
High insertion loss filter components like tunable bandpass filters(TBPF) are commonly used to tune the sideband output wavelengths in continuous-wave(CW) all-fiber optical parametric oscillators (FOPO). Aiming at reducing the high ring-cavity loss mainly caused by the insertion-loss of the bandpass filter, a low cavity-loss tunable CW FOPO based on multimode interference(MMI) filter was proposed. Cascaded single-mode-multimode-single-mode(SMS) fiber devices were fabricated as filter devices by selecting multimode fibers with different lengths and core-sizes. And their insertion-losses at selected wavelengths were less than 1 dB, and the total losses of the FOPO ring cavity were not more than 5 dB. By applying an axial pulling force to the SMS device to adjust the transmission spectrum of the filter device, the double-sideband output wavelengths could be tunable in the range of 1 494-1 501 nm and 1 638-1 629 nm.
2019, 48(5): 520003.
doi: 10.3788/IRLA201948.0520003
A broadband terahertz (THz) polarization beam splitter (PBS) was proposed. The PBS was based on subwavelength grating sandwiched between silica layers, which could split an arbitrarily polarized optical beam into two orthogonal, linearly polarized components, and then reflected the TE mode and transmit the TM mode. It was shown that THz PBS could efficiently operate from 3.5 THz to 5.5 THz, with high diffraction efficiencies and extinction ratios. In the process of PBS manufacture, there would be unavoidable deviations of the geometric parameters, which may affect its properties, i.e. the diffraction efficiencies and extinction ratios. Therefore, some structure parameters were calculated. Those values suggested that the designed PBS allows sufficient manufacture tolerances. When D1 ranged from 1 m to 1.2 m and thickness D3 ranged from 2.8 m to 3 m, the values of T0TM are always more than 96.9% and those of R0TE are more than 98.7%. And the values of Tc and Rc were respectively kept higher than 31 dB and 33.4 dB. These results show the PBS with a frequency bandwidth of 2 THz, a large angle range of 10, an extinction ratios over 20 dB and a diffraction efficiencies over 90%, is obtained. This work may inspire related studies and achieve some potential applications in THz manipulation system.
2019, 48(5): 520004.
doi: 10.3788/IRLA201948.0520004
Atom Trap Trace Analysis(ATTA) technology, which is based on the theory of laser cooling and trapping, has the capability of high-sensitivity detection of the radioactive isotope of Krypton and wide applications in the fields of geophysics and environmental science. Zeeman slower, as a key component of the ATTA instrument, is used to generate continuous atomic beam with low velocity. With the advantages of stable magnetic distribution, easy installment and debugging, no constant current power or cooling requirement, the Zeeman slower based on permanent magnet is getting more and more attention in recent years. In this paper, a Zeeman slower based on the toroidal permanent magnet was designed, the spatial distribution of the magnetic field of this slower was calculated by finite element analysis, a prototype was manufactured according to the design parameters, and its magnetic field along the axis was also measured. The lengths of the slower and its effective deceleration area were 51.2 cm and 46.9 cm, separately. The maximum deviation between the measured and theoretical magnetic field was less than 3.6 G, and the average deviation was 1.3 G. Furthermore, the deceleration process of the atomic beam in the designed and actual magnetic field distribution was simulated, and the influence of the radial variation of magnetic field distribution on the deceleration process of the atomic beam was analyzed. The result shows that the Zeeman slower in this paper is able to decelerate the velocity of the atomic beam with a diameter less than 20 mm from the maximum initial value of 250 m/s to the final value of 50 m/s.
2019, 48(4): 420001.
doi: 10.3788/IRLA201948.0420001
Optical interferometers are key devices in constructing aperture synthesis telescope. Compared with optical interferometers implemented with conventional discrete elements, integrated optical phase-shift interferometers possess ultra-compact structure, and thus can be applied in aperture synthesis telescope to optimize its structure and improve its stability as well. Silica based integrated optical phase-shift interferometer was studied, in aspects of its design, fabrication, as well as its characterization. Results show that the two direction couplers in interferometer chip possess well consistency in terms of their coupling efficiency, thanks to integrated optical waveguide technology itself. Excess loss of interferometer chip was measured to be as low as 1.8 dB, with uniformity of 0.1 dB. Phase shift error was estimated by measuring MZ interferometers, and results exhibit that error of 90 phase shifter is approximately 1.5 . Analysis show that silica based waveguide technology is promising in fabrication of optical phase-shift interferometers utilized in aperture synthesis telescope.
2019, 48(4): 420002.
doi: 10.3788/IRLA201948.0420002
The structural damage caused by micro-electro-mechanical system(MEMS) stress concentration in tunable vertical cavity surface emitting lasers(VCSEL) of GaAs-based and InP-based materials was studied. A bowknot MEMS cantilever structure was designed to reduce the von Mises stress at the fixed end of the cantilever and ensure the reliability of the device while ensuring the maximum displacement was invariable. The COMSOL software was used to optimize and analyze the influence of various parameters of the bowknot cantilever structure on the mechanical properties. The results show that the maximum von Mises stress at the fixed end of the optimized bowknot MEMS cantilever structure is reduced by 64% compared to the equal-section cantilever structure. The free spectral range of a bowknot MEMS wavelength-tunable VCSEL for GaAs-based materials is up to 45 nm.
2019, 48(3): 320001.
doi: 10.3788/IRLA201948.0320001
To verify the sensitivity of the single event transient effects of SiGe BiCMOS linear devices, a typical operational amplifier THS4304 and a voltage regulator TPS760 were selected to study the single event effects with pulsed laser. In the experiments, a method was proposed to determine the laser threshold energy of single event transient by gradual changing energy. And the sensitive region of single event effects within the device was analyzed by point-by-step scanning method. On this basis, the interaction between the pulse laser energy and the single event transient was analyzed, and the single event effects cross section was obtained, which provided a reference for the selection and application of the SiGe BiCMOS devices in the satellite electronic system and the design of the radiation hardening.
2019, 48(3): 320002.
doi: 10.3788/IRLA201948.0320002
In order to obtain high diffraction efficiency, high extinction ratio, wide spectrum, and large angle tolerance grating structure, a polarizing beam splitter with inverted trapezoidal double layer metal grating structure working in the near-infrared wavelength region was proposed. The PBS structure included a high refractive index dielectric layer and cut the photoresist of the grating region into an inverted trapezoidal structure, which increased the transmission efficiency and extinction ratio of the grating. Rigorous coupled-wave analysis method was used to simulate and optimize the polarization beam splitter parameters. The results show that more than 97% transmission efficiency of the transverse magnetic wave and over 95% reflection efficiency of the transverse electric wave can be achieved in the wavelength range from 1 290 to 1 840 nm. The corresponding maximum extinction ratios for the transmittance and reflectance are 33 dB and 53 dB, respectively. The proposed grating has an extinction ratios over 22 dB in the 1 550 nm wavelength and a large angle from -40 to 40, which meets the requirements for the high-performance polarizing beam splitters. Compared with the commonly used double layer metal rectangular gratings, the proposed inverted trapezoidal double layer structure exhibits higher transmittance and reflectance, which has greater design flexibility.
2019, 48(3): 320003.
doi: 10.3788/IRLA201948.0320003
The laser feedback technique had the advantage of high sensitivity, which could fulfill the displacement and deformation measurement of targets with black and rough surfaces without the need of cooperative target mirrors. In this paper, in order to eliminate the influences of environment (including air pressure, base vibration, drift in temperature, etc.) on measurement accuracy, steady orthogonally polarized microchip laser was designed and assembled. The orthogonally polarized laser feedback system was built with optical components and electric circuits. The system had capability to achieve long-distance measurement and work in steady state. The system could effectively reduce the influences of environment and improve the accuracy of the laser feedback interferometer.
2019, 48(3): 320004.
doi: 10.3788/IRLA201948.0302004
Based on the rigorous vectorial diffraction theory, the mechanism that the subwavelength gratings convert circular polarized light into linear polarized light was analyzed. Based on the analysis results, a design method of controlling polarization state of output beam with grating spatial distribution was proposed. Using this method, several subwavelength grating polarizers with annular gratings areas were designed. By changing the number of the annular gratings areas, different type of cylindrical vector beams can be obtained. Using the Richards-Wolf vectorial diffraction method, the amplitude and intensity distributions of the different components in the vicinity of focus were calculated on high numerical aperture condition. Most of the intensity distributions in the vicinity of focus were flattop distributions. The full width at half maxima of intensity is 1.541 in radial direction. Compared with other type of beams such as linearly polarized beam, radially polarized beam and azimuthally polarized beam, the optical performances of the output beams from the polarizers designed in this research are distinctly particular.
2019, 48(1): 120001.
doi: 10.3788/IRLA201948.0120001
A kind of multitap complex coefficient microwave photonic filter was proposed based on novel tunable multi-wavelength fiber laser and stimulated Brillouin scattering (SBS). The complex coefficient was realized based on a phase shift introduced by SBS. The phase shift was controlled by adjusting the pump power of SBS, and so the center frequency of the filter was adjusted continuously. 16 laser signals with wavelength intervals of 0.338 nm were obtained based on a tunable multi-wavelength high erbium doped fiber laser in experiment. And then, the influence on this filter by the length of SBS gain medium, the number of the taps and the wavelength interval were researched by simulation.
2019, 48(1): 120002.
doi: 10.3788/IRLA201948.0120002
Aimed at the light scattering problem from the particles on optical surfaces of the systems in practical applications, and taken Al2O3 particles in air as an example, the variations of the bidirectional reflection distribution function (BRDF) with the scattering angle on the surfaces of optical components were simulated and analyzed based on Mie scattering theory, and then the total integral scattering (TIS) value of the surface was calculated quantitatively. On this basis, the effect of the BRDF and the TIS value were further analyzed under the conditions of different air cleanliness levels, the direction of the optical component surface, the exposure time. The results indicate that, the air cleanliness levels, the direction of the optical component surface and the exposure time have effect on scattering of the optical surface, in which the direction of optical components has significant impact on the scattering of the surfaces. When the particles buildup on horizontal upward facing surfaces (TIS=3.9310-3), the amount of scattering increases by an order of magnitude compared with that of the vertical ones (TIS=4.0710-4), and increases by two orders of magnitude compared with that of the downward ones (TIS=5.2210-5). Finally, based on the Cassegrain telescope, aimed at the tolerance of the particles on the primary mirror, the exposure time reaching the tolerance was carried out with different air cleanliness levels. The results can provide reference for particle control and reliability for effective detection of the weak signal in practice.
2019, 48(1): 120003.
doi: 10.3788/IRLA201948.0120003
Aiming at the limitations of single pyroelectric infrared sensor (PIR) array in the target trajectory measurement, the method of using four PIR array sensing platforms to form the square perceptive model was put forward to measure the target trajectory. In this study, eight PIR probes were used to form M word array, with each probe evenly distributed at 45 degrees intervals. Four PIR array sensing platforms were arranged at the four vertices of the square model, and 32 senor angle data fusion through the adaptive weighted fusion algorithm of multi-sonsor data. At last, four sensing platforms used the coordinate and time information of the detected target to calculate the target's motion trajectory and obtained the target's speed. The experimental results show that this method can effectively make up for the deficiency of the function which can only realize positioning and low accuracy of single PIR array, and realize the accurate measurement of motion trajectory and the prediction of the target position in time sequence. So, this method has great theoretical significance and practical application value.
2019, 48(1): 120004.
doi: 10.3788/IRLA201948.0120004
ZnO-based photodetectors (PDs) have a small on/off ratio and long response time, which hamper their practical UV detection. Herein, a facile method to prepare a nanodiamond (ND)-decorated ZnO nanowire (ZNW) ultraviolet photodetector was demonstrated. This hybrid ZnO-ND UV photodetector considerably improved photodetection performance compared with bare ZnO. This hybrid device simultaneously exhibited remarkable detectivity, rapid response, and decent current on/off ratio. This excellent performance was attributed to the synergistic effect between NDs and the ZNWs. These results introduce a new scenario for designing and fabricating an innovative optoelectronic system.
2018, 47(S1): 99-104.
doi: 10.3788/IRLA201746.S120001
Out-of-band response is a very important parameter of UVFPA detectors. As a wide-gap semiconductor material, AlGaN based ultraviolet detector exhibits excellent performance of the out-of-band response and rejection in ultraviolet detection. Visible blind AlGaN 6408 pixel ultraviolet focal plane arrays (UVFPA) detector was reported, whose spectral response range is 345-363.5 nm. To characterize the out-of-band response of the detector over a wide spectral range, by monochromatic spectral scanning, a response spectrum of the UVFPA was obtained with a wide range from UV to near IR. The result shows that the UVFPA detector has an excellent performance of out-of-band response. The ratio is 1.14% over the whole spectral band from 300 to 1 160 nm.
2018, 47(S1): 105-111.
Traditional imaging limits to the occlusion of the solid medium such as the wall and can not collect the image of the object which is out of sight. Moreover, the speed of light is supposed to be infinite in traditional imaging, so the imaging process is a steady-state light transport and irrelevant to the time of flight of light, which cannot reveal the specific characteristic of object in the light transport. Single-photon imaging is a technology which can detect very weak photon signal and capture the information of distance, intensity and image of objects synchronously. In this paper, a method of transient imaging for hidden object was introduced. In the imaging process, the time of flight of photon was considered as a variable in light transport to realize transient imaging, combining imaging for hidden object with photon counting and using single-photon array detector as a receiver to reconstruct hidden object. Further, this method was demonstrated by simulation. It provides the basic theory and framework for the transient imaging of hidden object using single-photon array detector, which can help to design the imaging system in real world in the future, as well as to achieve a better understanding of the nature of transient imaging for hidden object.
In order to further optimize time and frequency domain characteristics of fast steering mirror (FSM) for image motion compensation and thus to increase the definition of picture taken by moving camera, a control system based on linear extended state observer(LESO), zero phase error tracking control(ZPETC) and Kalman filter was designed. First, mathematical model of FSM driven by voice coil motor(VCM) was established. Next, principles of LESO, ZPETC and Kalman filter were clarified. Finally, experimental research for controlled object was made. Step response curves demonstrate that the settling time reaches 2.5 ms. Besides, compared to proportional-integral-differential(PID) control system, relative error of output converges to zero faster when it is less than 1%. Bode diagram shows that the bandwidth attains 369 Hz, which is more than 1.5 times that of PID control system. Meanwhile, phase lag reduces nearly a half. When disturbance is added, average relative error of the designed system reaches 0.028%, reduced by 75% compared to that of PID control system. Pictures taken by camera illustrate that this control method makes both subjective visual effect and objective evaluation parameters of image improve further.
2018, 47(S1): 119-124.
doi: 10.3788/IRLA201847.S120004
The cutoff frequency of single mode, dispersion and loss of a novel terahertz polyethylene photonic crystal fiber with triangle core were investigated by using the full-vector finite element method (FEM). The results show that the terahertz frequency range of the single-mode is tailored by the cladding pitch, cladding air hole and core air hole diameters. 0.1-5 THz broadband single-mode transmission is obtained and waveguide dispersion is limited in 0.5 ps/(nmkm) for wavelength of 60-450 m, and the transmission loss is 2.67 dB/m at 2.8 THz.
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