Journals >Frontiers of Optoelectronics
Contents
2014
Volume: 7 Issue 1
15 Article(s)
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Research Article
Recent advances in development of vertical-cavity based short pulse source at 1.55 μm
Zhuang ZHAO, Sophie BOUCHOULE, Jean-Christophe HARMAND, Gilles PATRIARCHE, Guy AUBIN, and Jean-Louis OUDAR
This paper reviews and discusses recent developments in passively mode-locked vertical external cavity surface emitting lasers (ML-VECSELs) for short pulse generation at 1.55 μm. After comparing MLVECSELs to other options for short pulse generation, we reviewed the results of ML-VECSELs operating at telecommunication wThis paper reviews and discusses recent developments in passively mode-locked vertical external cavity surface emitting lasers (ML-VECSELs) for short pulse generation at 1.55 μm. After comparing MLVECSELs to other options for short pulse generation, we reviewed the results of ML-VECSELs operating at telecommunication wavelength and point out the challenges in achieving sub-picosecond operation from a MLVECSEL at 1.55 μm. We described our recent work in the VECSELs and semiconductor saturable absorber mirrors (SESAMs), their structure design, optimization and characterization, with the goal of moving the pulse width from picosecond to sub-picosecond..
Frontiers of Optoelectronics
- Publication Date: Jan. 01, 1900
- Vol. 7, Issue 1, 1 (2014)
Semitransparent organic solar cells
Furong ZHU
The organic solar cell technology has attracted great interests due to its potential of low cost solution process capability. Bulk heterojunction organic solar cells offer a potentially much cheaper alternative way to harness solar energy, and can be made flexible and large area. They can also be made translucent and iThe organic solar cell technology has attracted great interests due to its potential of low cost solution process capability. Bulk heterojunction organic solar cells offer a potentially much cheaper alternative way to harness solar energy, and can be made flexible and large area. They can also be made translucent and in different colors. As a result, the inexpensive fabrication process such as solutionprocess techniques, mechanical flexibility, light weight and visible-light transparency features make organic solar technology attractive for application in new markets, such as smart sensors, power generating window panes, building architecture, greenhouses and outdoor lifestyle, etc. After a brief overview of basics of organic photovoltaics, the enhancement of semitransparent organic solar cells over the two competing performance indices of power conversion efficiency and transmittance will be discussed..
Frontiers of Optoelectronics
- Publication Date: Jan. 01, 1900
- Vol. 7, Issue 1, 20 (2014)
Recent progress of traditional Chinese medical science based on theory of biophoton
Xiuxiu WANG, Jinzhao HUANG, Jinxiang HAN, Meina YANG, Jingxiang PANG, and Xiaolei ZHAO
With the development of biophotonics, biophoton detection technology has been appropriately used. In this paper, the main features and fundamental conceptions of biophotonics were introduced basically. Then the coherence theory of biophoton emission was reviewed. Furthermore, based on this coherence concept, the quantuWith the development of biophotonics, biophoton detection technology has been appropriately used. In this paper, the main features and fundamental conceptions of biophotonics were introduced basically. Then the coherence theory of biophoton emission was reviewed. Furthermore, based on this coherence concept, the quantum theory of traditional Chinese medicine (TCM) and properties of Chinese medicinal herbs were presented. To show the nature of biophoton emission in living systems and clarify its basic detection mechanism, high sensitive detection system which allows non-invasive and non-destructive (or less) recording was finally presented..
Frontiers of Optoelectronics
- Publication Date: Jan. 01, 1900
- Vol. 7, Issue 1, 28 (2014)
Hydrazine processed Cu2SnS3 thin film and their application for photovoltaic devices
Jun HAN, Ying ZHOU, Yang Tian, Ziheng HUANG, Xiaohua WANG, Jie ZHONG, Zhe XIA, Bo YANG, Haisheng SONG, and Jiang TANG
Copper tin sulfide (Cu2SnS3) was a potential earth abundant absorber material for photovoltaic device application. In this contribution, triclinic Cu2SnS3 film with phase pure composition and large grain size was fabricated from a hydrazine solution process using Cu, Sn and S as the precursors. Absorption measurement rCopper tin sulfide (Cu2SnS3) was a potential earth abundant absorber material for photovoltaic device application. In this contribution, triclinic Cu2SnS3 film with phase pure composition and large grain size was fabricated from a hydrazine solution process using Cu, Sn and S as the precursors. Absorption measurement revealed this Cu2SnS3 film had a direct optical band gap of 0.88 eV, and Hall effect measurement indicated the film was p-type with hole mobility of 0.86 cm2/Vs. Finally Mo/Cu2SnS3/CdS/ZnO/AZO/Au was produced and the best device efficiency achieved was 0.78%. Also, this device showed improved device performance during ambient storage. This study laid some foundation for the further improvement of Cu2SnS3 solar cell..
Frontiers of Optoelectronics
- Publication Date: Jan. 01, 1900
- Vol. 7, Issue 1, 37 (2014)
Texturization and rounded process of silicon wafers for heterojunction with intrinsic thin-layer solar cells
KunpengMA, Xiangbin ZENG, Qingsong LEI, Junming XUE, Yanzeng WANG, and Chenguang ZHAO
Heterojunction with intrinsic thin-layer (HIT) solar cells are sensitive to interface state density. Traditional texture process for silicon solar cells is not suitable for HIT one. Thus, sodium hydroxide (NaOH), isopropanol (IPA) and mixed additive were tentatively introduced for the texturization of HIT solar cells iHeterojunction with intrinsic thin-layer (HIT) solar cells are sensitive to interface state density. Traditional texture process for silicon solar cells is not suitable for HIT one. Thus, sodium hydroxide (NaOH), isopropanol (IPA) and mixed additive were tentatively introduced for the texturization of HIT solar cells in this study. Then, a mixture including nitric acid (HNO3), hydrofluoric acid (HF) and glacial acetic acid (CH3COOH) was employed to round pyramid structure. The morphology of textured surface and the influence of etching time on surface reflectance were studied, and the relationship between etching time and surface reflectance, vertex angle of pyramid structure was analyzed. It was found that the mixture consisting of 1.1 wt% NaOH, 3 vol% IPA and 0.3 vol% additives with etching time of 22.5 min is the best for HIT solar cells under the condition of 80°C. Uniform pyramid structure was observed and the base width of pyramid was about 2-4 μm. The average surface reflectance was 11.68%. Finally the effect of different processes on the performance of HIT solar cells was investigated. It was shown that these texturization and rounding techniques used in this study can increase short circuit current (Jsc), but they have little influence on fill factor (FF) and open circuit voltage (Voc) of HIT solar cells..
Frontiers of Optoelectronics
- Publication Date: Jan. 01, 1900
- Vol. 7, Issue 1, 46 (2014)
Misalignments among stacked layers of metamaterial terahertz absorbers
Yinghui GUO, Lianshan YAN, Wei PAN, Bin LUO, Xiantao ZHANG, and Xiangang LUO
Misalignment among stacked layers of absorbers is inevitable in practice. Adverse effects induced by this undesired factor was investigated and analyzed in this paper. The absorption responses of thin terahertz metamaterial (MM) absorber with different degree of misalignment were simulated by finite-difference time-domMisalignment among stacked layers of absorbers is inevitable in practice. Adverse effects induced by this undesired factor was investigated and analyzed in this paper. The absorption responses of thin terahertz metamaterial (MM) absorber with different degree of misalignment were simulated by finite-difference time-domain (FDTD) method under both transverse magnetic (TM) and transverse electric (TE) polarization. Results show that slight misalignment deteriorates absorption response due to the decreased spatial resolution. The analyses are given in terms of the magnetic field distribution in the cross section. In addition, the depravation is changed with polarization, which depends on the direction of excursion..
Frontiers of Optoelectronics
- Publication Date: Jan. 01, 1900
- Vol. 7, Issue 1, 53 (2014)
A micro-spectrometer with phase modulation array
Tao YANG, Yuchao CHEN, Xing’ao LI, Wei HUANG, and Yongyuan ZHU
A micro-spectrometer with phase modulation array is investigated in this paper. The vital component of this micro-spectrometer is a micro-interferometer array, which is built on a charge-coupled device (CCD) or a complementary metal oxide semiconductor (CMOS). Each element of micro-interferometer array is formed by polA micro-spectrometer with phase modulation array is investigated in this paper. The vital component of this micro-spectrometer is a micro-interferometer array, which is built on a charge-coupled device (CCD) or a complementary metal oxide semiconductor (CMOS). Each element of micro-interferometer array is formed by polymethyl methacrylate (PMMA) grooves with different depth. When we illuminate the surface of the interferometer array, different interference intensity distribution would be formed at the bottom of each micro-interferometer. Optical power of this interferometer can be measured by the pixels of CCD or CMOS. The data can be substituted into a linear system. By solving the linear system with Tikhonov regularization method, spectrum of the incident beam can be reconstructed. Simulation results prove that the detection range of the spectrometer is a wide wavelength range covering from 300 to 1100 nm. Furthermore, the wavelength resolution of the device reaches picometer level. In comparison with conventional spectrometers, the novel spectrometer has distinct advantages of small size, low cost, high resolution, wide spectral measurement range, real-time measurement, and so on..
Frontiers of Optoelectronics
- Publication Date: Jan. 01, 1900
- Vol. 7, Issue 1, 59 (2014)
Boltzmann constant determined by fluorescent spectroscopy for verifying thermometers
Weiwei ZHANG, Yiqing GAO, and Xingdao HE
As is always accompanying temperature in physics fundamental principles, Boltzmann constant kB can be used to verify the accuracy of a thermometer. This paper presents a photoluminescent method to measure kB via temperature dependent fluorescence of phosphors. Diagram of a phosphor’s energy levels was simplified to illAs is always accompanying temperature in physics fundamental principles, Boltzmann constant kB can be used to verify the accuracy of a thermometer. This paper presents a photoluminescent method to measure kB via temperature dependent fluorescence of phosphors. Diagram of a phosphor’s energy levels was simplified to illustrate the principle of measurement. The relationship between kB and h*c (Planck constant h multiplying light speed in vacuum c) was experimentally derived. Finally, the determined kB was 1.38065×10-23 J/K. The determination could give a value of (1.38±0.1)×10-23 J/K even when the in-use spectrometer was with a poor resolution as about 2 nm. At the end, optimization of measuring conditions for the determination process was suggested..
Frontiers of Optoelectronics
- Publication Date: Jan. 01, 1900
- Vol. 7, Issue 1, 64 (2014)
Simulation analysis of combined UV/blue photodetector in CMOS process by technology computer-aided design
Changping CHEN, Xiangliang JIN, Lizhen TANG, Hongjiao YANG, and Jun LUO
A composite ultraviolet (UV)/blue photodetector structure has been proposed, which is composed of P-type silicon substrate, Pwell, Nwell and N-channel metaloxide-semiconductor field-effect transistor (NMOSFET) realized in the Pwell. In this photodetector, lateral ringshaped Pwell-Nwell junction was used to separate theA composite ultraviolet (UV)/blue photodetector structure has been proposed, which is composed of P-type silicon substrate, Pwell, Nwell and N-channel metaloxide-semiconductor field-effect transistor (NMOSFET) realized in the Pwell. In this photodetector, lateral ringshaped Pwell-Nwell junction was used to separate the photogenerated carriers, and non-equilibrium excess hole was injected to the Pwell bulk for changing the bulk potential and shifting the NMOSFET’s threshold voltage as well as the output drain current. By technology computer-aided design (TCAD) device, simulation and analysis of this proposed photodetector were carried out. Simulation results show that the combined photodetector has enhanced responsivity to UV/blue spectrum. Moreover, it exhibits very high sensitivity to weak and especially ultral-weak optical light. A sensitivity of 7000 A/W was obtained when an incident optical power of 0.01 μW was illuminated to the photodetector, which is 35000 times higher than the responsivity of a conventional silicon-based UV photodiode (usually is about 0.2 A/W). As a result, this proposed combined photodetector has great potential values for UV applications..
Frontiers of Optoelectronics
- Publication Date: Jan. 01, 1900
- Vol. 7, Issue 1, 69 (2014)
Multiband infrared luminescence of Er3+-Ho3+-Nd3+/Tm3+-codoped telluride glasses
Yaojing ZHANG, Lu SUN, Ying CHANG, Wenbin LI, and Chun JIANG
This paper reports the simultaneous emissions around 1.53, 1.80, 2.10, 2.70 and 3.00 μm in Er3+-Ho3+-Nd3+/Tm3+-codoped telluride glasses upon excitation of a conventional 808 nm laser diode. Both emission bands of 1.53 and 2.70 μm were assigned to the transitions of 4I13/2-4I15/2, 4I11/2 -4I13/2 of Er3+ ions, respectivThis paper reports the simultaneous emissions around 1.53, 1.80, 2.10, 2.70 and 3.00 μm in Er3+-Ho3+-Nd3+/Tm3+-codoped telluride glasses upon excitation of a conventional 808 nm laser diode. Both emission bands of 1.53 and 2.70 μm were assigned to the transitions of 4I13/2-4I15/2, 4I11/2 -4I13/2 of Er3+ ions, respectively, the emission near 1.80 mm was assigned to the transition 4F4 -4H6 of Tm3+ ions, and the emissions at 2.10 and 3.00 mm arose from the transitions of 5I7 -5I8, 5I6 -5I7 of Ho3+ ions. The materials are promising for ultra-broad band amplified spontaneous emission optical sources at near and middle infrared region..
Frontiers of Optoelectronics
- Publication Date: Jan. 01, 1900
- Vol. 7, Issue 1, 74 (2014)
Edge effect of optical surfacing process with different data extension algorithms
Yang LIU, Haobo CHENG, Zhichao DONG, and Hon-Yuen TAM
This study presents a strategy which integrates extra polishing path (EPP) and error map extension to weaken the edge effect in the ultraprecise optical surfacing process. Different data extension algorithms were presented and analyzed. The neighbor-hood average can be selected as the frequently-used method, as it has This study presents a strategy which integrates extra polishing path (EPP) and error map extension to weaken the edge effect in the ultraprecise optical surfacing process. Different data extension algorithms were presented and analyzed. The neighbor-hood average can be selected as the frequently-used method, as it has not bad precision and time-saving performance for most surface forms through the simulation results and practical experiment. The final error map was obtained, its peak-to-valley (PV) was 0.273l and root mean square (RMS) was 0.028l (l=632.8 nm). The edge effect was weakened and suppressed well through the experiment..
Frontiers of Optoelectronics
- Publication Date: Jan. 01, 1900
- Vol. 7, Issue 1, 77 (2014)
InAs/GaAs far infrared quantum ring inter-subband photodetector
Mohammad KARIMI, Kambiz ABEDI, and Mahdi ZAVVARI
In this paper, we presented a numerical analysis of absorption coefficient, dark current and specific detectivity for InAs/GaAs quantum ring inter-subband photodetector (QRIP). 3D Schrodinger equation was solved using finite difference method and based on effective mass approximation. Dimensions of quantum ring (QR) weIn this paper, we presented a numerical analysis of absorption coefficient, dark current and specific detectivity for InAs/GaAs quantum ring inter-subband photodetector (QRIP). 3D Schrodinger equation was solved using finite difference method and based on effective mass approximation. Dimensions of quantum ring (QR) were considered that inter-subband transition was to be accomplished for radiations of 20 μm. Resonant tunneling (RT) barriers were designed with tunneling probability of unity for electrons with energy of 0.062 meV to lower dark current of conventional QRIP. Numerical analyses show that inclusion of RT barriers can reduce dark current for about two orders of magnitude. Furthermore, specific detectivities for conventional QRIP and RT-QRIP were calculated respectively, and results at different temperatures were compared. It is suggested that specific detectivity for RT-QRIP is one order of magnitude higher than that for conventional QRIP. It is suggested that RT barriers considerably improve the specific detectivity of conventional QRIP at different temperatures..
Frontiers of Optoelectronics
- Publication Date: Jan. 01, 1900
- Vol. 7, Issue 1, 84 (2014)
Climate effects on performance of free space optical communication systems in Yemen
Abdulsalam G. ALKHOLIDI, and Khalil S. ALTOWIJ
Free space optical (FSO) communication has been considered as an alternative to radio relay link line-ofsight (LOS) communication systems. The total attenuation is a combination of atmospheric attenuation in the atmosphere and geometric losses. The purpose of this paper is to study the geometric loss versus link range Free space optical (FSO) communication has been considered as an alternative to radio relay link line-ofsight (LOS) communication systems. The total attenuation is a combination of atmospheric attenuation in the atmosphere and geometric losses. The purpose of this paper is to study the geometric loss versus link range (in km), divergence angle, transmitter aperture diameter, and receiver aperture diameter. Total attenuation versus low visibility, average visibility, beam divergence, link range and rainfall rate were presented in this paper. Atmospheric attenuation (in dB) and scattering coefficient (in km-1) for several Yemeni main cities were explored. The study was concentrated on received power versus low and average visibilities and link range. Series of related simulation results were illustrated and discussed in this paper about the climate effects on performance of FSO communication systems in Yemen..
Frontiers of Optoelectronics
- Publication Date: Jan. 01, 1900
- Vol. 7, Issue 1, 91 (2014)
Beam shaping of high power diode laser stack into homogeneous line
Mokhtar SLIMANI, Jun LIU, Jianguo XIN, and Jiabin CHEN
In this paper, analysis of beam shaping and homogenization of high power diode laser stack into a line focus with dimension of 10 mm×0.5 mm was reported. The beam shaping and homogenization was simulated by using ZemaX-ray tracing technique. The results have shown that intensity distribution after beam shaping andIn this paper, analysis of beam shaping and homogenization of high power diode laser stack into a line focus with dimension of 10 mm×0.5 mm was reported. The beam shaping and homogenization was simulated by using ZemaX-ray tracing technique. The results have shown that intensity distribution after beam shaping and homogenization at the work piece is a flat top for the slow axis with homogeneity over 95% and a Gaussian distribution for the fast axis..
Frontiers of Optoelectronics
- Publication Date: Jan. 01, 1900
- Vol. 7, Issue 1, 102 (2014)
Laser diode corner pumped Nd:KGW slab laser
H. AMAN, B. HUSSAIN, and A. AMAN
This paper reports the continuous wave (CW) and Q-switched operation of a diode pumped KGd (WO4):Nd (Nd:KGW) slab laser with a corner pumped geometry at the wavelength of 1067 nm. With an optical conversion efficiency of 38% and 34%, average powers of 23 and 20 W in CW and Q-switched modes were achieved respectively. TThis paper reports the continuous wave (CW) and Q-switched operation of a diode pumped KGd (WO4):Nd (Nd:KGW) slab laser with a corner pumped geometry at the wavelength of 1067 nm. With an optical conversion efficiency of 38% and 34%, average powers of 23 and 20 W in CW and Q-switched modes were achieved respectively. The maximum pulse energy of 27 mJ was observed with a repetition rate of 840 Hz..
Frontiers of Optoelectronics
- Publication Date: Jan. 01, 1900
- Vol. 7, Issue 1, 107 (2014)
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