- 标题
- 摘要
- 关键词
- 实验方案
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Spectral filtering of photovoltaic cells using novel bio-filter: Silver coated Hibiscus extract using methanol solution
摘要： Spectra filtering is a fairly new concept to control the damaging contributions of solar IR radiations to photovoltaic (PV) cells or panel. In this research, the bio-filter was synthesized and tested. The bio-filter was proposed as the panacea to filtering the solar IR radiations. The bio-filter performance was adjudged to show little success, as it was 3% lower than the normal performance in the monocrystalline solar PV panel and 50% higher than the normal performance in the polycrystalline solar PV panel. The varying results in the polycrystalline and monocrystalline PV panels may arise as a result of unequal coating of the panel. Hence, the coating technique is recommended to be uniform and precise in further research work.
关键词： bio-filter,Hibiscus extract,photovoltaic cells,methanol solution,spectral filtering
更新于2025-09-23 15:19:57
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Reflection in-line and off-axis hybrid digital holography
摘要： We propose an in-line and off-axis hybrid holographic method for imaging reflective objects. The in-line and off-axis digital holograms are recorded by a Michelson interferometer. The approximate phase of object wave is obtained by spectral filtering approach from the off-axis hologram, and it is used as an initial input in an iterative procedure for retrieving the complex field of the object from the in-line hologram. In this way, the output of the iterative procedure can produce higher quality amplitude and phase images compared to only in-line or off-axis digital holography. The performance of this method has been demonstrated by acquiring the amplitude and phase images of a resolution target and a microelectronic chip.
关键词： Reflective object,Phase retrieval,Spectral filtering,Digital holography
更新于2025-09-16 10:30:52
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Effect of spectral filtering on pulse duration in dissipative soliton resonance (DSR) regime of modelocked fiber laser
摘要： The effect of spectral filtering on pulse duration in an all-normal-dispersion laser operating in a dissipative soliton resonance (DSR) regime is studied numerically and compared with the results obtained by solving the analytical expressions. It is observed that the spectral filtering reduces the pulse duration in the DSR regime. The numerically simulated trend of the variation of flat-top pulse duration as a function of the gain for different spectral transmission bandwidths of the filter shows good qualitative agreement with the experimental results.
关键词： modelocked fiber laser,pulse duration,spectral filtering,dissipative soliton resonance
更新于2025-09-16 10:30:52
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - All-Polarization-Maintaining Dual-Color/Dual-Comb Yb:Fiber Laser
摘要： Dual-comb spectroscopy systems based on two pulse trains emitted from a single laser cavity benefit from passive mutual coherence between the two pulse trains, which leads to common-mode noise cancellation in the down converted radio-frequency (RF)-comb [1]. Due to their robustness, single cavity dual-color/dual-comb fiber lasers are promising candidates for such spectroscopy systems [2,3]. Here, we present a novel method to generate two pulse trains out of a single fiber laser cavity based on mechanical spectral filtering, which offers two key features: dynamical adjustment of the spectral separation between the two pulse trains and tuning of the difference in repetition rates. After demonstrating the concept in a 23-MHz nonlinear polarization evolution (NPE) mode-locked ytterbium (Yb) laser [4], we have now for the first time implemented this concept in a nonlinear amplified loop mirror (NALM) mode-locked all-polarization maintaining (PM) Yb:fiber laser operating at a repetition rate of 77 MHz, thus improving both the stability as well as the non-aliasing dual-comb bandwidth. The laser contains a free-space arm with a transmission grating compressor, in which the spectral components of the intra-cavity light are spatially dispersed (Fig.1(a)). By introducing a small beam block into the grating compressor, we split the spectrum into two separate regions. We show that these two spectral regions can be independently mode-locked, thus creating two pulse trains with slightly different repetition rates (Fig.1(b-d)). Due to the spatial distribution of the spectral components, we can vary the width of the spectral cut between the two spectra by rotating the beam block (Fig. 1(b), blue curves). Furthermore, adjusting the grating spacing (and thus the amount of dispersion) allows us to tune the difference in the repetition rate ?frep from 1-6 kHz (Fig. 1(e)). After spectral separation at the cavity output, the pulse centered around 1030 nm is amplified and broadened in a nonlinear fiber to create a spectral overlap with the 1060 nm-pulse (Fig. 1(f)). The overlapping spectrum is bandpass-filtered around 1055 nm and sent onto a photodiode (PD). An oscilloscope trace of the PD output shows interferograms (Fig. 1(f), inset) occurring with a periodicity of 1/?frep, which correspond to the Fourier-transform of the down-converted RF comb that is generated by the beating of both optical combs.
关键词： repetition rate tuning,polarization maintaining,Yb:fiber laser,spectral filtering,Dual-comb spectroscopy
更新于2025-09-11 14:15:04