Ultrafast evanescently coupled waveguide MUTC-PDs with high responsivity.

Novel evanescently coupled waveguide modified uni-traveling carrier photodiodes (MUTC-PDs) employing a thick multi-layer coupling waveguide are reported. To improve the optical-to-electrical (O/E) conversion efficiency, a thick multi-layer coupling waveguide with a gradually increased refractive index from the bottom layer to the absorption layer is utilized. The refractive index profile facilitates the upward transmission of incident light into the absorption region, thereby enhancing the evanescent coupling efficiency. Meanwhile, the coupling waveguide, with a total thickness of 1.75 µm, expands the mode field diameter, thereby reducing the input coupling loss. Additionally, the top layer of the coupling waveguide also serves as the drift layer. This configuration facilitates efficient light absorption within a short PD length, thus ensuring ultrawide bandwidth and high O/E conversion efficiency simultaneously. Without an additional spot size coupler or anti-reflection coating, the measured responsivity is as high as 0.38 A/W for the PD with an active area of 5 × 6 µm2. Meanwhile, an ultrawide 3-dB bandwidth of 153 GHz has been demonstrated.

Transfer-printed, tandem microscale light-emitting diodes for full-color displays.

Inorganic semiconductor-based microscale light-emitting diodes (micro-LEDs) have been widely considered the key solution to next-generation, ubiquitous lighting and display systems, with their efficiency, brightness, contrast, stability, and dynamic response superior to liquid crystal or organic-based counterparts. However, the reduction of micro-LED sizes leads to the deteriorated device performance and increased difficulties in manufacturing. Here, we report a tandem device scheme based on stacked red, green, and blue (RGB) micro-LEDs, for the realization of full-color lighting and displays. Thin-film micro-LEDs (size ∼100 µm, thickness ∼5 µm) based on III-V compound semiconductors are vertically assembled via epitaxial liftoff and transfer printing. A thin-film dielectric-based optical filter serves as a wavelength-selective interface for performance enhancement. Furthermore, we prototype arrays of tandem RGB micro-LEDs and demonstrate display capabilities. These materials and device strategies provide a viable path to advanced lighting and display systems.

Ultrafast MUTC photodiodes over 200†GHz with high saturation power.

Novel back-illuminated modified uni-traveling-carrier photodiodes (MUTC-PDs) with wide bandwidth and high saturation power are demonstrated. The effect of cliff layer doping on the electric field distribution is investigated to achieve fast carrier transport. MUTC-PDs with miniaturized device diameter and low contact resistance are fabricated to improve the RC-limited bandwidth. Meanwhile, inductive peaking is implemented to further extend the bandwidth. PDs with 3-µm and 3.6-µm-diameter exhibit a ultrawide bandwidth of 230 GHz and 200 GHz, together with -4.94 dBm and -2.14 dBm saturation power at 220 GHz and 200 GHz, respectively.

Extended ray-mapping method based on differentiable ray-tracing for non-paraxial and off-axis freeform illumination lens design.

The ray-mapping method has been widely used for designing freeform illumination lenses. However, in non-paraxial or off-axis situations, it remains challenging to obtain an integrable ray-mapping, often requiring a complex iterative correction process for the initial mapping. To address this challenge, we propose an extended ray-mapping method that incorporates differentiable ray-tracing into the design pipeline of the ray-mapping method. This enables accurate surface construction according to ray-mapping and efficient shape correction based on irradiance distribution. The proposed method involves two optimization stages. In the first stage, the freeform surface is preliminarily optimized to closely match the optimal transport mapping. The obtained freeform surface is then further optimized in the second stage to minimize the divergence between the target and simulated irradiance distributions. Additionally, the mean curvature of the freeform surface is also constrained in the second stage to facilitate the fabrication of the final freeform surface. Non-paraxial illumination lenses and off-axis illumination lenses have been designed using the proposed method within ten minutes, and simulations demonstrate that the approach is effective and robust.

Simple and accurate dispersion measurement of GaN microresonators with a fiber ring.

The dispersion characteristics of a microresonator are important for applications in nonlinear optics, and precise measurement of the dispersion profile is crucial to device design and optimization. Here we demonstrate the dispersion measurement of high-quality-factor gallium nitride (GaN) microrings by a single-mode fiber ring, which is simple and convenient to access. Once the dispersion parameters of the fiber ring have been determined by the opto-electric modulation method, the dispersion can be obtained from the microresonator dispersion profile by polynomial fitting. To further verify the accuracy of the proposed method, the dispersion of the GaN microrings is also evaluated with frequency comb-based spectroscopy. Dispersion profiles obtained with both methods are in good agreement with simulations based on the finite element method.

Efficient surface defect identification for optical components via multi-scale mixed Kernels and structural re-parameterization.

Surface defect identification plays a vital role in defective component rapid screening tasks in optics-related industries. However, the weakness and complexity of optical surface defects pose considerable challenges to their effective identification. To this end, a deep network based on multi-scale mixed kernels and structural re-parameterization is proposed to identify four manufacturing and two non-manufacturing optical surface defects. First, we design a multi-size mixed convolutional kernel with multiple receptive fields to extract rich shallow features for characterizing the defects with varying scales and irregular shapes. Then, we design an asymmetric mixed kernel integrating square, horizontal, vertical, and point convolutions to capture rotationally robust middle-and-deep features. Moreover, a structural re-parameterization strategy is introduced to equivalently convert the multi-branch architecture in the training phase into a deploy-friendly single-branch architecture in the inference phase, so that the model can obtain higher inference speed without losing any performance. Experiments on an optical surface defect dataset demonstrate that the proposed method is efficient and effective. It achieves a remarkable accuracy of 97.39% and an ultra-fast inference speed of 201.76 frames/second with only 5.23M parameters. Such a favorable accuracy-speed trade-off is capable of meeting the requirements of real-world optical surface defect identification applications.

Suppression of mid-spatial-frequency waviness by a universal random tree-shaped path in robotic bonnet polishing.

Mid-spatial-frequency (MSF) errors seriously damages the imaging performance of optical components. Path pattern is an important factor that affects the generation of MSF waviness in polishing. This paper proposes a versatile pseudo random tree-shaped path (RTSP) generation method imitating the growth rules of tree branch in nature, which can efficiently generate continuous, uniformly distributed and multi-directional paths on a specified surface. Furthermore, the effectiveness of RTSP to suppress MSF waviness is verified by numerical simulation and experimental results. Finally, the RTSP is applied to the polishing of Ti-6Al-4V titanium alloy mirror. Results indicate that grinding marks have been significantly removed, while no obvious MSF waviness is introduced.

Membrane multiple quantum well electro-optical modulator employing low loss high-k radio-frequency slot waveguides.

A membrane multiple quantum well (MQW) electro-optical (EO) modulator exploiting low loss high-k radio-frequency (RF) slot waveguides is proposed for sub-terahertz bandwidth. By employing high-k barium titanate (BTO) claddings in place of doped InP cladding layers in traditional InP-based MQW modulators, the proposed modulator exhibits enhanced modulation efficiency and bandwidth as well as reduced insertion loss. A low half-wave voltage-length product of 0.24 V·cm is estimated, together with over 240 GHz bandwidth for a 2-mm-long modulation region, thus allowing sub-terahertz operation.

Reduction of mid-spatial frequency errors on aspheric and freeform optics by circular-random path polishing.

Pseudo-random paths are a useful tool to reduce mid-spatial frequency errors created in the processing of optical surfaces by sub-aperture polishing tools. Several types of patterns have been proposed, including hexagonal, square and circular, but prior literature has largely focused on flat and gently curved surfaces. Here, an extension of the circular-random path to strongly curved aspheric and freeform surfaces is proposed. The main feature of the algorithm is to cover the entire surface to be polished with a uniformly distributed tool path. Aspheric condenser lenses are then polished with a regular raster and circular-random path. Analysis of the optical performance shows that the random path can reduce the amplitude of mid-spatial frequency errors and relative intensity of satellite images. These features are particularly desirable in short wavelength applications, such as mirrors for EUV and X-ray.

A single-chip multi-beam steering optical phased array: design rules and simulations.

A waveguide-based multi-beam steering device is proposed for light detection and ranging (LIDAR). The device integrates binary gratings with an optical phased array (OPA), thus enabling a single-chip LIDAR system. The device can provide an N×M beam array that covers a wide angular range while phase shifters help realize steering over a narrow angle range between the beams. The antenna structure for 1D beam splitting is realized by combining the design of a grating coupler and a beam splitter grating, and a uniform beam splitting is achieved along the other dimension using non-uniformly distributed antennas. To illustrate the design, an OPA with an 11×11 beam array is designed at a wavelength of 905 nm. The OPA achieves a wide total field of view (FOV) of 68.8° × 77° with a narrow beam-array-steering angle of 6.5°, enabling a wide-FOV 3D sensing with a high frame rate.

Virtually imaged phased-array-based 2D nonmechanical beam-steering device for FMCW LiDAR.

Nonmechanical beam-steering devices are of importance to achieve fast, compact, and reliable LiDAR. We propose a 2D nonmechanical beam-steering device based on a virtually imaged phased array (VIPA) for frequency-modulated continuous-wave (FMCW) LiDAR. In the design, 2D nonmechanical beam steering and high-resolution FMCW ranging can be achieved at the same time by wavelength tuning. The design formulas of the VIPA-based 2D disperser are greatly simplified by introducing appropriate approximation, and a feasible design procedure is proposed for the first time, to the best of our knowledge. Based on the proposed method, several design examples with different optimal properties are exhibited.

[Expression of Runt-related Transcription Factor 3 in Human Colon Cancer Cell Line HCT-116 Resistant to 5-Fluorouracil and the Mechanism of Drug Resistance].

Objective To establish a human colon cancer cell line HCT-116/5-FU resistant to 5-fluorouracil(5-FU)and explore the relationship between runt-related transcription factor 3(RUNX3)and drug resistance of colorectal cancer.Methods The human colon cancer cell line HCT-116/5-FU with resistance to 5-FU was established by low concentration gradient increment combined with high-dose intermittent shock.CCK-8 method was used to determine the half maximal inhibitory concentration(IC50)of 5-FU on the parent line HCT-116 and drug-resistant line HCT-116/5-FU.The cell growth curve was established for the calculation of population doubling time(TD).The mRNA levels and protein levels of RUNX3,P-glycoprotein(P-gp),multidrug resistance-associated protein 1(MRP1),and lung resistance-related protein(LRP)in HCT-116 and HCT-116/5-FU cells were determined by qRT-PCR and Western blotting,respectively.The RUNX3 expression in HCT-116 cells was knocked down by siRNA technique,and the cells were divided into RUNX3 knockdown groups(si-RUNX3-1 group and si-RUNX3-2 group)and negative control group(si-NC group).The knockdown efficiency was verified by qRT-PCR at the mRNA level and Western blotting at the protein level.The IC50 in si-RUNX3 groups and si-NC group was determined with CCK-8 method,and the expression of P-gp,MRP1,and LRP in the two groups was detected by Western blotting.Results A stable human colon cancer drug-resistant cell line HCT-116/5-FU was successfully constructed.HCT-116/5-FU showed the TD 1.38 times as long as that of HCT-116(P=0.002)and changed morphology.The mRNA level of RUNX3 in HCT-116/5-FU cells was significantly lower than that in HCT-116 cells(P=0.048),and those of P-gp(P=0.008),MRP1(P=0.001),and LRP(P=0.001)showed the opposite trend.The protein level of RUNX3 in HCT-116/5-FU cells was significantly lower than that in HCT-116(P<0.001),and those of P-gp,MRP1,and LRP presented the opposite trend(all P<0.001).The HCT-116 cell model with low expression of RUNX3 was successfully established.The mRNA level of RUNX3 had no significant difference between si-RUNX3-1 group and si-NC group(P=0.064),while the level in si-RUNX3-2 group was significantly lower than that in si-NC group(P=0.034).The protein levels of RUNX3 in si-RUNX3-1 group and si-RUNX3-2 group were lower than that in si-NC group(both P<0.001).The results demonstrated higher knocking efficiency in si-RUNX3-2 group,which was thus selected to complete the follow-up test.The IC50 of si-RUNX3 group was significantly higher than that of si-NC group(P<0.001),which indicated that the down-regulated expression of RUNX3 could reduce the sensitivity of HCT-116 cells to 5-FU.The relative protein levels of P-gp,MRP1,and LRP in si-RUNX3 group were significantly higher than those in si-NC group(all P<0.001).Conclusion The down-regulation of RUNX3 expression can reduce the sensitivity of HCT-116 cells to 5-FU,which is considered to be related to the up-regulated expression of P-gp,MRP1,and LRP.

Chromatically multi-focal optics based on micro-lens array design.

CCD arrays encode color information via uniformly distributed red, green and blue pixels. Therefore, even a perfectly achromatic system projecting an image onto a CCD plane cannot possibly associate a single object point with the 3 or more discrete pixels encoding color content. Here, we propose and demonstrate a micro-lens array (MLA) design that simultaneously corrects chromatic aberrations and separates color channels to spatially distinct pixels. Starting from a commercially available aspheric condenser lens, methods to design and assess the performance of a few microns deep MLA etched on the convex optical surface are detailed. Actual fabrication is carried out by fluid jet polishing, with an optical form deviation of 0.24 µm rms. Finally, the MLA is assessed with a narrowly collimated beam containing two wavelengths, which produces distinct spots of diameter 10-15 µm as expected.

Ginsenoside Rg1 Inhibits Cell Proliferation and Induces Markers of Cell Senescence in CD34+CD38- Leukemia Stem Cells Derived from KG1α Acute Myeloid Leukemia Cells by Activating the Sirtuin 1 (SIRT1)/Tuberous Sclerosis Complex 2 (TSC2) Signaling Pathway.

BACKGROUND Clinical relapse in acute myeloid leukemia (AML) is associated with the reduced treatment response of leukemia stem cells (LSCs). This study aimed to investigate the effects of the ginseng derivative, ginsenoside Rg1 (Rg1), on CD34+CD38- LSCs derived from KG1a human acute myeloid leukemia cells. MATERIAL AND METHODS CD34+CD38- LSCs were isolated from KG1a human acute myeloid leukemia cells by cell sorting. CD34+CD38- KG1alpha LSCs were divided into the control group and the Rg1 group (treated with Rg1). The cell counting kit-8 (CCK-8) assay evaluated the proliferation of CD34+CD38- KG1alpha LSCs and flow cytometry studied the cell cycle. The mixed colony-forming unit (CFU-Mix) assay and staining for senescence-associated beta-galactosidase (SA-ß-Gal) evaluated cell senescence. Expression of sirtuin 1 (SIRT1) and tuberous sclerosis complex 2 (TSC2) were evaluated using Western blot and quantitative reverse transcription-polymerase chain reaction (qRT-PCR). RESULTS CD34+CD38- KG1alpha LSCs were isolated at 98.72%. Rg1 significantly reduced the proliferation of CD34+CD38- KG1alpha LSCs compared with the control group (p<0.05). Cells in the G0/G1 phase were significantly increased, and cells in the G2/M and S phase were significantly reduced compared with the control group (p<0.05). Rg1 significantly increased SA-ß-Gal and reduced CFU-Mix formation compared with the control group (p<0.05), significantly down-regulated SIRT1 expression in CD34+CD38- KG1alpha LSCs compared with the control group (p<0.05), and significantly reduced TSC2 expression in CD34+CD38- KG1alpha LSCs compared with the control group (p<0.05). CONCLUSIONS Rg1 inhibited cell proliferation and induced cell senescence markers in CD34+CD38- KG1alpha LSCs by activating the SIRT1/TSC2 signaling pathway.

[Effect of ginsenoside Rg_1 in delaying premature ovarian failure induced by D-gal in mice through PI3K/Akt/mTOR autophagy pathway].

The aim of this paper was to study the role of phosphoinositide 3-kinase(PI3 K), protein kinase B(Akt) and mamma-lian target of rapamycin(mTOR) in the inhibition of premature ovarian failure induced by D-galactose(D-gal) in mice model by ginsenoside Rg_1(Rg_1). Fifty-four female SPF BALB/c mice were randomly divided into PBS group, D-gal group, and Rg_1 group. In the D-gal group, D-galactose(200 mg·kg~(-1)·d~(-1)) was injected subcutaneously into the neck and back for 42 days. In the PBS group, an equal amount of phosphate buffered saline(PBS) was injected into the neck and back for 42 days. In addition to the therapy of D-gal group, Rg_1 group was given Rg_1(20 mg·kg~(-1)·d~(-1)) through intraperitoneal injection since the 15 th day for 28 days, at the same time, the D-gal group and the PBS group were also given an equal amount of PBS through intraperitoneal injection since the 15 th day for 28 days. After the treatment, the estrous cycle changes of the mice were detected, and the ovarian SA-ß-Gal staining was used to detect the changes of ovarian aging. Western blot was used to detect the changes in protein expressions of PI3 K, Akt, mTOR, S6 k, LC3-Ⅱ and P16~(INK4 a). Fluorescence quantitative PCR was used to detect the changes in mRNA expressions of PI3 K, Akt, mTOR, S6 k, LC3-Ⅱ and P16~(INK4 a). According to the findings, compared with the PBS group, the D-gal group began to show estrous cycle disorder in the 3 rd week,the ovarian SA-ß-Gal staining positive granulosa cells increased in the D-gal group, the expression of senescence marker P16~(INK4 a) increased, while the expression of autophagy signaling molecule LC3-Ⅱ decreased. After treatment with Rg_1, the positive rate of ovarian SA-ß-Gal staining in Rg_1 group decreased, the expression level of autophagy signaling molecule LC3-Ⅱ in Rg_1 group was higher than that in D-gal group, while the expression level of senescence marker P16~(INK4 a) was lower than that in D-gal group. Compared with the PBS group, the protein and mRNA expressions of PI3 K, Akt, mTOR and S6 k in the D-gal group were up-regulated, the protein expressions of Akt, mTOR and S6 k in the Rg_1 group were up-regulated, and the mRNA expressions of PI3 K and mTOR were up-regulated. After treatment with Rg_1, the protein expressions of PI3 K, Akt, mTOR and S6 k in the Rg_1 group were lower than those in the D-gal group, while the mRNA expressions of Akt, mTOR and S6 k in the Rg_1 group were lower than those in the D-gal group. The finding ssuggested that Rg_1 has the effect in delaying ovarian premature failure in D-gal-induced mouse models, and PI3 K/Akt/mTOR autophagy signaling pathways play an important role.

Laser frequency noise characterization by self-heterodyne with both long and short delay.

We propose a novel approach to laser frequency noise characterization by delayed self-heterodyne. Compared with the traditional treatment, our method applies to both long and short delay, corresponding to uncorrelated and correlated self-heterodyne. In the case of long delay, it overcomes the influence of 1/f noise on the intrinsic linewidth extraction from a broadened spectrum, and the results are more accurate than Voigt profile fitting. For short delayed correlated heterodyne, it eliminates artifact peaks at multiples of the reciprocal of delay time introduced by transferring measured RF phase noise to laser phase noise, thus extending the measurement range. In addition, it calibrates the frequency noise overestimation caused by a finite noise floor. This method remains valid when the delay and the coherence time are comparable. Experimental results are presented to demonstrate the effectiveness of the proposed approach in characterizing lasers with intrinsic linewidth ranging from sub-100 Hz to megahertz.

[Ginsenoside Rg_1 induces leukemia stem cell senescence via SIRT1/TSC_2 signal axis].

The aim of this paper was to investigate the effect of SIRT1/TSC_2 signal axis on leukemia stem cell senescence induced by ginsenoside Rg_1. CD34~+CD38~- leukemia stem cells(CD34~+CD38~-LSCs) was isolated by magnetic cell sorting(MACS) and divided into two groups. The control group cells were routinely cultured, 40 µmol·L~(-1) ginsenoside Rg_1 was added to the control group for co-culture in Rg_1 group. The effect of Rg_l to induce CD34~+CD38~-LSCs senescence were evaluated by senescence-associated ß-Galactosidase(SA-ß-Gal) staining, cell cycle assay, CCK-8 and Colony-Assay. The expression of senescence associated SIRT1, TSC_2 mRNA and protein was examined by Real-time fluorescence quantitative PCR(FQ-PCR) and Western blot. The results showed that the CD34~+CD38~-LSCs could effectively be isolated by MACS, and the purity of CD34~+CD38~-LSCs is up to(95.86±3.04)%. Compared with the control group, the percentage of positive cells expressed SA-ß-Gal in the Rg_1 group is increased, the senescence morphological changes were observed in the CD34~+CD38~-LSCs in the Rg_1 group. The proliferation inhibition rate and the number of cells entered G_0/G_1 phase in the Rg_1 group were increased, but the colony-formed ability was decreased, Rg_1 could significantly inhibit the proliferation and self-renewal ability of CD34~+CD38~-LSCs. The expression of SIRT1 and TSC_2 mRNA and protein were down regulated in the Rg_1 group compared with the control group. Our research implied that Rg_1 may induce the senescence of CD34~+CD38~-LSCs and SIRT1/TSC_2 signal axis plays a significant role in this process.

Improving modulation bandwidth of c-plane GaN-based light-emitting diodes by an ultra-thin quantum wells design.

The GaN-based light emitting diodes (LEDs) have a great potential for visible light communication (VLC) due to their ubiquitous application in general lighting, but the modulation bandwidth of conventional c-plane LEDs is limited by carrier recombination rate in InGaN quantum wells (QWs) due to the polarization-field-induced quantum confined Stark effect (QCSE). Furthermore, the high modulation bandwidth on c-plane sapphire substrates can only be achieved at high current densities. Here, blue LEDs with ultra-thin InGaN QWs (1nm) and GaN barriers (3nm) are grown on c-plane sapphire substrate to suppress QCSE and extend the cut-off frequency from 214 MHz for conventional LEDs to 536 MHz at a current density of 2.5 kA/cm2, which is comparable to devices grown on semi-polar substrates.

Aluminum nitride-on-sapphire platform for integrated high-Q microresonators.

We demonstrate aluminum nitride (AlN) on sapphire as a novel platform for integrated optics. High-confinement AlN microring resonators are realized by adopting a partially etched (pedestal) waveguide to relax the required etching selectivity for exact pattern transfer. A wide taper is employed at the chip end facets to ensure a low fiber-to-chip coupling loss of ~2.8 dB/facet for both transverse-electric (TE) and transverse-magnetic (TM) modes. Furthermore, the intrinsic quality factors (Qint) recorded with a high-resolution linewidth measurement are up to ~2.5 and 1.9 million at telecom band for fundamental TE00 and TM00 modes, corresponding to a low intracavity propagation loss of ~0.14 and 0.2 dB/cm as well as high resonant buildup of 473 and 327, respectively. Such high-Q AlN-on-sapphire microresonators are believed to be very promising for on-chip nonlinear optics.

Synthesis characterization and cytotoxicity studies of platinum(II) complexes with reduced amino pyridine schiff base and its derivatives as ligands.

A series of reduced amino pyridine Schiff base platinum(II) complexes were prepared as potential anticancer drugs, and characterized by NMR, IR spectroscopy, elemental analysis, and molar conductivity. UV and CD results showed the binding mode between these compounds and salmon sperm DNA may be intercalation. The cytotoxicity of these complexes was validated against A549, Hela, and MCF-7 cell lines by MTT assay. Some complexes exhibited better cytotoxic activity than cisplatin against Hela and MCF-7 cell lines.