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- 实验方案
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Highly Sensitive Polarization Photodetection Using a Pseudo-One-Dimensional Nb <sub/> (1– <i>x</i> ) </sub> Ti <sub/><i>x</i> </sub> S <sub/>3</sub> Alloy
摘要： Low-symmetry layered two-dimensional (2D) materials with strong in-plane optical anisotropy can potentially be applied for polarization photodetection. This is especially true for those 2D materials with a direct bandgap, who can efficiently absorb light with specific axial polarization. However, discovering such new anisotropic 2D materials with direct band structure is still extremely challenging. Here, we fabricate a photodetector using a pseudo-one-dimensional (pseudo-1D) Nb(1-x)TixS3 alloy device, and demonstrate that it is highly sensitive to the polarized light due to the strong in-plane optical anisotropy and direct bandgap of the alloy by combining the angle-resolved polarization Raman spectroscopy (ARPRS), azimuth-dependent reflectance difference microscopy (ADRDM), polarization-dependent absorption spectroscopy (PDAS), and hybrid functional theory calculations. As a consequence, the polarization photodetector of the Nb(1-x)TixS3 alloy shows a large photocurrent anisotropic ratio and a high photoresponse. The choice of low-symmetry layered pseudo-1D Nb(1-x)TixS3 alloy in polarization photodetection might open up new functionalities for novel optoelectronic device applications.
关键词： low-symmetry structure,in-plane optical anisotropy,pseudo-one-dimensional materials,Nb(1-x)TixS3 ternary alloy,polarization-sensitive photodetector
更新于2025-09-23 15:23:52
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Piezo-phototronic effect enhanced polarization-sensitive photodetectors based on cation-mixed organica??inorganic perovskite nanowires
摘要： Piezo-phototronic effect has been extensively investigated for the third generation semiconductor nanowires. Here, we present a demonstration that piezo-phototronic effect can even be applied to tune polarization-sensitive photodetectors based on cation-mixed organic–inorganic perovskite nanowires. A big anisotropic photoluminescence (PL) with linearly polarized light-excitation was found due to a strong spontaneous piezoelectric polarization besides the anisotropic crystal structure and morphology. The piezo-phototronic effect was utilized to tune the PL intensity, and an improved anisotropic PL ratio from 9.36 to 10.21 for linearly polarized light-excitation was obtained thanks to the modulation by piezo-potential. And a circularly polarization-sensitive PL characterized with circular dichroism ratio was also discovered, which was found to be modulated from 0.085 to 0.555 (with a 5.5-fold improvement) within the range of applied strain. The circular dichroism was resulted from the joint effects of the modulated Rashba spin–orbit coupling and the asymmetric carriers separation and recombination for right- and left-handed helicity due to the presence of effective piezo-potential. These findings not only reveal the promising optoelectronic applications of piezo-phototronic effect in perovskite-based polarization-sensitive photodetectors, but also illuminate fundamental understandings of their polarization properties of perovskite nanowires.
关键词： polarization-sensitive photodetectors,perovskite nanowires,Rashba spin–orbit coupling,Piezo-phototronic effect,photoluminescence
更新于2025-09-23 15:21:01
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Birefringence measurement of biological tissue based on polarization-sensitive digital holographic microscopy
摘要： We present a polarization-sensitive digital holography to measure the birefringence of biological tissues with complex structures. The birefringence measurement system is established by incorporating the modified Mach–Zehnder interferometer and lab-developed software. Normal and cancerous bladder tissue samples are measured by using the proposed experimental system. The polarization-dependent phase-shifted holograms are recorded by rotating the polarizer. Moreover, the hybrid reconstruction and least-square unwrapping algorithms are used to extract phase information of biological tissues at different polarization states. The birefringence of tissue is obtained from the above-phase distributions. The results show that polarization sensitivity exists in the normal bladder tissue and cancerous bladder tissue, and the median birefringence value of the cancerous tissue is significantly higher than that of the normal tissue. These results will provide reference for pathological research and clinic diagnoses.
关键词： Mach–Zehnder interferometer,birefringence,polarization-sensitive digital holography,biological tissue,phase distribution
更新于2025-09-23 15:21:01
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Simultaneous Investigation of Vascular and Retinal Pigment Epithelial Pathologies of Exudative Macular Diseases by Multifunctional Optical Coherence Tomography
摘要： To investigate exudative macular disease, multifunctional optical coherence tomography (MF-OCT) using a 1-lm probe band was developed. The clinical utility of MF-OCT was examined in a descriptive case series. METHODS. Ten eyes of nine subjects with exudative macular disease, including one eye with age-related macular degeneration (AMD), one eye with idiopathic neovascular maculopathy, and eight eyes with polypoidal choroidal vasculopathy (PCV), were investigated. Areas of 6 3 6 mm2 around the pathologic region were scanned with 512 3 1024 depth scans in 6.6 seconds. Structural OCT, Doppler optical coherence angiography (OCA), and cumulative phase retardation images were obtained with a single measurement. Each MF-OCT image visualized the structure, vasculature, and birefringence. Degree of polarization uniformity values were also obtained for selective visualization of the retinal pigment epithelium (RPE). The MF-OCT images were compared with conventional ophthalmic images. RESULTS. Abnormal vasculatures were observed with Doppler OCA in all eyes, which presented high similarity to indocyanine green angiography in the midphase. The RPE and exudation in the pathologic regions were discriminated in one eye with AMD and ?ve of eight eyes with PCV. Cumulative phase retardation visualized ?brosis scars in two of the PCV cases. CONCLUSIONS. Multifunctional OCT revealed depth-resolved abnormal vasculatures, the integrity of the RPE and choroid, discrimination of the RPE and exudation, and existence of ?brosis scars in exudative macular diseases. Interpretation of MF-OCT examination is well matched with conventional ophthalmic examination. These results suggest that MF-OCT can be used as a noninvasive ophthalmic examination tool prior to conventional examinations in clinical routines.
关键词： polarization-sensitive OCT,OCT angiography,optical coherence tomography,retinal pigment epithelium,exudative macular disease
更新于2025-09-23 15:21:01
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Polarization-Sensitive Self-Powered Type-II GeSe/MoS2 Van der Waals Heterojunction Photodetector
摘要： Polarization-sensitive photodetectors are highly desirable for high performance optical signal capture and stray light shielding in order to enhance the capability for detection and identification of targets in the dark, haze and other complex environments. Usually, filters and polarizers are utilized for conventional devices to achieve polarization-sensitive detection. Herein, to simplify the optical system, a 2-D self-powered polarization-sensitive photodetector is fabricated based on a stacked GeSe/MoS2 van der Waals (vdWs) heterojunction which facilitates efficient separation and transportation of the photogenerated carriers, due to type-II band alignment. Accordingly, a high performance self-powered photodetector is achieved with merits of a very large on-off ratio photocurrent at zero bias of currently 104 and a high responsivity (Rλ) of 105 mA/W with the external quantum efficiency (EQE) of 24.2%. Furthermore, a broad spectral photoresponse is extended from 380 nm to 1064 nm owing to the high absorption coefficient in a wide spectral region. One of the key benefits from these highly anisotropic orthorhombic structures of layered GeSe is self-powered polarization sensitive detection with a peak/valley ratio up to 2.95. This is realized irradiating with a 532 nm wavelength laser with which a maximum photoresponsivity of up to 590 mA/W is reached when the input polarization is parallel to the armchair direction. This work provides a facile route to fabricate self-powered polarization-sensitive photodetectors from GeSe/MoS2 vdW heterojunctions for integrated optoelectronic devices.
关键词： polarization sensitive photodetector,self-powered,type-II band alignment,GeSe/MoS2 heterojunction,broad spectral photoresponse
更新于2025-09-23 15:19:57
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Solution-processed one-dimensional CsCu <sub/>2</sub> I <sub/>3</sub> nanowires for polarization-sensitive and flexible ultraviolet photodetectors
摘要： Polarization-sensitive ultraviolet (UV) photodetectors are highly desired due to their great significance in many applications. As the newly-emerging functional semiconductors, the metal-halide perovskites have attracted huge attention in photodetection due to their excellent optoelectronic features. However, the ever-reported perovskites polarized photodetectors mainly focused on the visible/infrared-light region, and the devices targeted at the UV region have not been reported. Here, for the first time, ternary copper halides CsCu2I3 nanowire was used as the light absorber to achieve polarization-sensitive UV photodetection. By combining the intrinsic anisotropy of the asymmetry structure and external morphology anisotropy of CsCu2I3 nanowires, a record photocurrent anisotropy ratio of ~3.16 was achieved, and also the shortcomings of lead-toxicity and environmental instability for conventional lead-halide perovskites were overcome effectively. Moreover, such photodetectors fabricated on flexible substrate demonstrate good flexibility and stability, showing almost no photoresponse degradation after extremely bending for 1000 cycles. The results suggest that the lead-free CsCu2I3 nanowire is potentially an attractive candidate for high-performance polarization-sensitive UV photodetectors compatible for practical applications.
关键词： CsCu2I3 nanowires,Polarization-sensitive,metal-halide perovskites,lead-free,ultraviolet photodetectors,flexible substrate
更新于2025-09-19 17:13:59
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Exploiting Bulk Photovoltaic Effect in a 2D Trilayered Hybrid Ferroelectric for Highly Sensitive Polarized Light Detection
摘要： Polarized light detection is attracting increasing attention for its wide applications ranging from optical switches to high-resolution photodetectors. Two-dimensional (2D) hybrid perovskite-type ferroelectrics combining inherent light polarization dependence of bulk photovoltaic effect (BPVE) with their excellent semiconducting performances present significant potential in this portfolio. Here, we first report the BPVE-driven highly sensitive polarized light detection in a 2D trilayered hybrid perovskite ferroelectric, (allyammonium)2(ethylammonium)2Pb3Br10 (1), which shows superior BPVE with a near-bandgap photovoltage of ~ 2.5 V and a high on/off switching ratio of current (~ 104). Notably, driven by the superior BPVE, 1 exhibits highly sensitive polarized light detection with a polarization ratio as high as ~15, which is far more beyond than those of structural anisotropy-based monocomponent devices. As far as we know, this is the first realization of BPVE-driven polarized light detection in hybrid perovskite ferroelectrics. This work opens a new avenue for the design of highly sensitive polarized light detection by exploiting the sinusoidal behavior of BPVE current in 2D multilayered hybrid perovskite ferroelectrics.
关键词： Ferroelectric photovoltaic,Two-dimensional hybrid perovskite,Polarization-sensitive photodetection,Bulk photovoltaic effect,Ferroelectric material
更新于2025-09-12 10:27:22
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Exploiting Bulk Photovoltaic Effect in a 2D Trilayered Hybrid Ferroelectric for Highly Sensitive Polarized Light Detection
摘要： Polarized light detection is attracting increasing attention for its wide applications ranging from optical switches to high-resolution photodetectors. Two-dimensional (2D) hybrid perovskite-type ferroelectrics combining inherent light polarization dependence of bulk photovoltaic effect (BPVE) with their excellent semiconducting performances present significant potential in this portfolio. Here, we first report the BPVE-driven highly sensitive polarized light detection in a 2D trilayered hybrid perovskite ferroelectric, (allyammonium)2(ethylammonium)2Pb3Br10 (1), which shows superior BPVE with a near-bandgap photovoltage of ~ 2.5 V and a high on/off switching ratio of current (~ 104). Notably, driven by the superior BPVE, 1 exhibits highly sensitive polarized light detection with a polarization ratio as high as ~15, which is far more beyond than those of structural anisotropy-based monocomponent devices. As far as we know, this is the first realization of BPVE-driven polarized light detection in hybrid perovskite ferroelectrics. This work opens a new avenue for the design of highly sensitive polarized light detection by exploiting the sinusoidal behavior of BPVE current in 2D multilayered hybrid perovskite ferroelectrics.
关键词： Ferroelectric photovoltaic,Two-dimensional hybrid perovskite,Polarization-sensitive photodetection,Bulk photovoltaic effect,Ferroelectric material
更新于2025-09-12 10:27:22
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Mapping of Corneal Layer Thicknesses With Polarization-Sensitive Optical Coherence Tomography Using a Conical Scan Pattern
摘要： PURPOSE. We demonstrate segmentation and mapping of corneal layers (epithelium, Bowman’s layer, and stroma) across the entire cornea (limbus to limbus), using additional contrast provided by polarization-sensitive optical coherence tomography (PS-OCT) and analyze the reproducibility of the procedure. METHODS. A custom built PS-OCT system operating at 1045 nm central wavelength with conical scanning was used for image acquisition. Conical scanning allows for almost perpendicular beam incidence on the corneal surface and provides good signal quality over the entire ?eld of view. Epithelium, Bowman’s layer, and stroma were segmented using the additional contrast provided by PS-OCT. Thickness maps were computed and analyzed in sectors. Both eyes of 20 healthy volunteers were imaged at least three times to test this method and to quantify reproducibility. RESULTS. Thickness maps of the epithelium show signi?cant (P < 0.001) superior thinning and an inferior thickening. Bowman’s layer appears homogeneous within the central 7 to 8 mm diameter of the cornea and gets thinner toward the periphery until this layer disappears between 4 and 5.5 mm eccentricity from the center. Intersubject variations of the measured thicknesses of epithelium (coef?cient of variation [CV] ~8%), Bowman’s layer (CV~25%), and stroma (CV~10%) were observed. Very good reproducibility of thickness measurements of epithelium (CV < 3%), Bowman’s layer (CV < 5%), and stroma (CV < 2%) was found. Furthermore, a signi?cant correlation (P < 0.001) between layer thicknesses of the right and left eyes of the same subject was found. CONCLUSIONS. PS-OCT with conical scanning is a feasible approach for determining thickness maps of corneal layers on a large ?eld of view with high reproducibility.
关键词： cornea,optical coherence tomography,polarization-sensitive imaging,corneal epithelium,Bowman’s layer
更新于2025-09-10 09:29:36
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A polarization sensitive light scattering unit for high throughput screening
摘要： A simple, effective light scattering prototype sensitive to both polarized and depolarized scattering was constructed, and its performance was tested on a variety of pure liquids and optically isotropic and anisotropic polymer solutions and colloidal suspensions. The results, performance, and means to further improvement are reported here. Because of its simplicity and low cost, many identical units can be produced to construct a simultaneous multiple sample light scattering platform that can be used to monitor polymer and colloid solution stability, phase changes, aggregation, degradation, etc. Measurable depolarization was found for a variety of organic liquids and suspensions of both poly?uoroethylene and latex spheres. No detectable depolarization was found for various polymers.
关键词： light scattering,depolarized scattering,colloidal suspensions,polymer solutions,high throughput screening,polarization sensitive
更新于2025-09-10 09:29:36