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Tumor hypoxia is a feature of tumor micro-environment (TME), which provides a suitable environment for tumor cells migration and invasion. However, up to now, the function of exosomes derived from hypoxic tumor cells is still not fully understood. The present study is aimed to explore the underlying mechanisms of lung cancer-secreted exosomes-mediated tumor metastasis under hypoxia.Exosomes were isolated from normoxic or hypoxic NCI-H446 cells. Some characteristic proteins were detected by western blots. Levels of CD63, CD 9 and CD 81 proteins were up-regulated on the membrane of exosomes secreted by hypoxic NCI-H446 cells. Basing on the results from miRNA sequencing, qRT-PCR and wound healing assay, hsa-miR-625-3p was discovered to be accumulated inside hypoxic exosomes and responsible for the metastasis of lung cancer cell. Further experiments from luciferase reporter gene assay demonstrated hsa-miR-625-3p could directly inhibit SCAI expression through binding with its 3'UTR, which suggested the mechanisms by which exosomal hsa-miR-625-3p suppressed tumor cells migration.Exosomal miR-625-3p derived from hypoxic small lung cancer cells accelerated tumor cells migration through inhibiting SCAI directly.

Background Malignant pleural mesothelioma (MPM) is a rare tumor in the pleura. This study was carried out to identify key genes and pathways that may be involved in MPM. Methods Microarray datasets GSE51024 and GSE2549 were analyzed for differentially expressed genes (DEGs) between normal and MPM tissues. The identified DEGs were subjected to functional analyses using bioinformatics tools. Results A total of 276 DEGs were identified, consisting of 187 downregulated and 79 upregulated genes. Gene ontology and Kyoto encyclopedia of genes and genomes pathway enrichment analysis indicated that the DEGs were enriched in extracellular structure organization, extracellular matrix, and ECM−receptor interaction. Due to high degree of connectivity among 24 hub genes, EZH2 and HMMR are likely to play roles in the carcinogenesis and progression of MPM. The two genes were found over-expressed in MPM tissues. Patients with elevated EZH2 and HMMR expressions had poor overall survival. Conclusions EZH2 and HMMR are identified to be the hub genes for MPM and they may be further characterized to better understand the molecular mechanisms underlying the carcinogenesis of MPM.

The present study aimed to identify a key module of differentially expressed miRNAs (DE-miRNAs) together with the corresponding differentially expressed mRNAs (DE-mRNAs) within small cell lung cancer (SCLC). Linear models were applied to ascertain the DE-miRNAs and DE-mRNAs in SCLC versus matched non-carcinoma samples obtained from the RNA expression datasets of GSE19945, GSE74190 and GSE6044. The common DE-miRNAs were identified using the Venn plot. Then, 3 databases were used to retrieve the DE-miRNAs target genes, and the intersection was taken for validating the shared target genes. Besides, Cytoscape was utilized for constructing the miRNAmRNA network for SCLC. Finally, a key module of five DE-miRNAs and four hub genes was determined based on the degree. In addition, the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were conducted for exploring those hub genes in terms of their functions along with the involved signal transduction pathways. Altogether 106 shared DE-miRNAs were identified, which were used to predict 63 common target genes. In addition, a key module of five DE-miRNAs (hsa-miR-17-5p, hsa-miR-20a-5p, hsa-miR-20b-5p, hsa-miR-93-5p and hsa-miR- 106b-5p) and four hub genes (SOX4, DPYSL2, TGFBR2 and F3) were extracted from the miRNAmRNA network according to their degree. Finally, the hub genes were subjected to GO as well as KEGG analysis, which revealed that cell cycle G1/S phase transition, the extracellular matrix, and cellular senescence signaling pathways exerted vial parts during SCLC progression. A key module of five DE-miRNAs and four hub genes may be potentially used as clinical biomarkers to predict SCLC.

We present a scale-adaptive three-dimensional (3D) imaging architecture for coherent light detection and ranging (lidar) that incorporates Risley-prism-based beam scanning. An inverse design paradigm from beam steering to prism rotation is developed for demand-oriented beam scan pattern generation and prism motion law formulation, which allows the lidar to perform 3D imaging with adaptive scale and configurable resolution. By combining flexible beam manipulation with simultaneous distance and velocity measurement, the proposed architecture can achieve both large-scale scene reconstruction for situational awareness and small-scale object identification against long range. The experiment results demonstrate that our architecture enables the lidar to recover a 3D scene in a ±30° field of view and also focus on distant objects at over 500 m with spatial resolution up to 1.1 cm.

Visual surveillance systems play a vital role in smart manufacturing scenes. In this paper, a cooperative camera surveillance method is proposed based on the coarse-fine coupling boresight adjustment principle. A master-slave camera cooperative monitoring model is established by combining a high-resolution camera with a large-field camera, the former of which is embedded with a Risley prism pair to perform high-precision boresight pointing for monitoring a local target, while the latter can observe a wide scene and guide the former to catch a region of interest. An effective boresight adjustment strategy is put forward with a method of combining fast convergence and iterative refinement. A calibration method of the master-slave camera is proposed with the combination of binocular vision and equivalent motion plane. The error distribution, adjustment efficiency and tracking accuracy of the dual field monitoring are analyzed in detail to reveal the mapping mechanism between imaging feedback and boresight adjustment. In the surveillance experiment, the root-mean-square tracking error of the fine tracking camera can achieve better than 7.04 pixels, while the adjustment steps only need about 10 times, which validates the feasibility and effectiveness of the proposed method in industrial operation surveillance.

Purpose To compare clinicopathologic factors including tumor-node-metastasis (TNM) stage between young and elderly patients with non-small cell lung cancer (NSCLC). Methods This retrospective study compared the following characteristics between 52 young patients with NSCLC ( 60 years): duration of symptoms before medical consultation, smoking index, family history of cancer, Ki-67 index, and pTNM stage. A binary logistic regression analysis was used to identify factors predictive of greater stage NSCLC (stage III/IV compared to stage I/II) within each age group. Results The incidence of adenocarcinoma was higher in the young than in the elderly (P=0.006). Smoking index (P=0.002) and Ki-67 index (P

Laser pointing unit using tilting orthogonal double prisms (TODP) opens up a promising avenue for fine pointing in free-space laser communication, which can steer the laser beam with a pointing precision upon submicroradian order. How to obtain accurate inverse solutions is a basic issue for TODP systems. In this paper, a lookup-table method combined with the binary search procedure is demonstrated, and an iterative method that converges to the inverse solution by gradually reducing the search region is also investigated. The simulation results show that both methods can reach the pointing precision of micrometer order (namely submicroradian order after unit conversion) at a pointing distance of 400 mm, which can well meet the requirement of high-accuracy laser beam pointing applications.

The rise of heteromorphic architecture brings great challenges to engineering design, blanking, construction, completion testing, and maintenance. The 3D laser scanning measurement technology can quickly achieve the “copy” measurement of the target, especially suitable for the digitization of complex structure and the accurate construction of true 3D model and it takes care of other things which are necessary environment point of view. In this paper, we are considering the steel structure inspection and curtain wall blanking in the construction of the Grand Theater in the “Shangqiu Cultural and Art Center” as a case study. First, the laser scanning technology has been introduced to complete the data acquisition of steel structure objects and to screen the other details of the structure. Then, the high-quality point cloud is obtained through multistation splicing, filtering, denoising and smoothing, compression, and simplification. Through field comparison, the point cloud accuracy reached an acceptable level. Through field comparison, it can be seen that the difference between the designed building model combining laser technology and BIM technology is distributed within the range of ±(1–5)mm, and the mean square error is ±3.5 mm, and the deviation of numerical simulation is small, which meets the building requirements. Therefore, this method can effectively detect steel structure, and the BIM model can be updated according to the measured point cloud data. We provide accurate data reference for curtain wall material and installation.

Due to the maturity of VCSEL supply chain promoted by the VCSEL applications in smart phones, and the increasing peak power of multi-junction VCSEL chip，VCSELs are considered to have great advantages and potential as the transmitter light sources of automotive low-cost LIDAR devices. Here we introduce a kind of VCSEL line-beam module with unique optical shaping design for LiDAR applications. The module has a uniform line beam with a peak power larger than 200W, a pulse width of 4ns, a divergence angle of 0.12° @ 1/e2, and the vertical axis intensity uniformity is better than 80%. The experimental data showed that over a wide temperature range from - 40 °C to 110 °C the power variation of the line beam module is less than 20%, the variation of horizontal divergence angle is less than 5%, and the temperature drift coefficient is 0.066nm/°C, which greatly reduces the performance requirements of the receiver detector for the Lidar system. In addition, we introduce a prototype of new line-beam modules with peak power higer than 1000W we are developing, which can meet further requirement of long-distance LiDAR system.

With the development of laser technology, high power diode lasers have found the increasing various applications in many fields, including industry, advanced manufacturing, aerospace, Lidar and medical systems etc.. The near field non-linearity (Smile) and lasing uniformity of emitters for high power diode laser arrays are critical to high reliable optically coupled modules and laser heads in a cladding system. In order to obtain the lower smile and higher lasing uniformity, two CTEmatched substrates (Copper Tungsten-CuW) are employed to bond a single GaAs-based diode laser array with the cavity length of 2mm on a Micro Channel Cooler (MCC) using Gold-Tin hard solder. This double-CuW MCC-packaged structure is called DMCC which enables a diode laser array bonded on a CuW/MCC/CuW structure with all AuSn solder. Structural optimization has been carried out to reduce the thermal stress and smile for this package. Simulation results indicate that the smile and thermal stress is lowered 0.24μm and 16MPa, respectively. According to the simulation results, single bar DMCC-packaged diode lasers with lower Smile value are fabricated and characterized. The experimental results show that the ratio of Smile (average smile ~0.87μm) l1μm is ~71% and higher ~19% than that of conventional structure (average smile ~1.2μm). Importantly, the quantity ratio of lasing emitters (≥46 emitters) in a diode laser array is significantly raised from ~62% to 85% after the optimization of CuW submount.

Three products based on VCSEL chips are developed for intelligent driving Lidar and driver monitor system. The line beam products used for long-distance detection achieved a 0.1°horizontal divergence angle, 23° vertical divergence angle, and the vertical beam uniformity more than 80%. For the area beam products used in medium and short distance detection, has achieved the field of view 125°×25°. For the super wide field of view area beam product, can applied in driver monitor system, the FOV is 160°×120°. These three products all have excellent performance in a wide temperature range (- 40 degrees centigrade ~ 110 degrees centigrade).

A thermal tunability metamaterial absorber with single-band absorption properties is proposed and numerical verification. An absorption peak can be revealed at resonant wavelength 1.54 m at room temperature. The metal parameter condition is optimized in simulation in order to improve the property of this absorber. Simulated results reveal that absorption performances can be modulated based on the refractive index changes. High FOM values are obtained based on water or glucose solution. Moreover, the resonance wavelength and amplitude are modulated based on the ambient temperature changes. Finally, the effect of central metal particle side width or dielectric layer thickness at room temperature on absorption performances are also revealed in simulation.

In this work, a visual colorimetric method for the rapid and selective detection of triacetone triperoxide is reported. This visual colorimetric method is based on the reaction between potassium titanyl oxalate and hydrogen peroxide (H2O2) released from triacetone triperoxide degradation. Potassium titanyl oxalate can selectively react with H2O2 to form peroxo-titanic acid (an orange complex), enabling the colorimetric detection of triacetone triperoxide. Based on the theory that triacetone triperoxide produces hydrogen peroxide under acidic conditions, acid types, acid concentration, response time, visual limit of detection, and reactants ratio are systematically studied simultaneously for this colorimetric method. Under sulfuric acid concentration is 60%, the proposed method can almost detect triacetone triperoxide instantly, and the color of the solution reaches the maximum within 1 min and remains stable with a visual limit of detection as low as 3.0 × 10−5 mol/L. Interference experiments were carried out on other kinds of explosives (hexamethylene triperoxide diamine, trinitrotoluene, etc.). The use of colorimetric card brings great convenience to the rapid, qualitative, and semi-quantitative on-site detection of triacetone triperoxide. Because of its rapidity, high sensitivity, simplicity, and selectivity, the proposed visual colorimetric method can serve as a valuable and promising reference for triacetone triperoxide’s rapid, qualitative on-site detection.

High power diode lasers (HPDLs) offer the highest wall-plug efficiency, highest specific power (Power-to-weight ratio) and arguably the lowest cost and highest reliability among all lasers, especially compared to fiber lasers and diode pumped solid state lasers (DPSSLs). However, in today’ real applications, the market is still dominated by fiber lasers and DPSSLs although direct diode laser applications are growing. The more widespread applications and thus higher market growth of HPDLs are limited by the poor beam quality of HPDLs. Naturally, one of directions of HPDL technologies is to improve the beam quality from semiconductor design and fabrication point of view. On the other hand, for most of the applications no matter it is laser matter interaction or information transmitting or illumination, three factors determine if a laser can be used for a specific application: power density, beam shape, intensity profile. It is known that beam shaping is the process of redistributing the irradiance and phase of a beam of optical radiation. Although the etendue of a light source can only remain constant or increase as light propagates through an optical system, the beam parameter product (BPP) of a light source can be reduced in one direction with the sacrifice of the other direction by beam shaping. Beam shaping micro-optics have the possibility to control and deliver photons emitted by light sources to the right place at the right time. To unlock the potential of HPDLs and make light energy emitted from HPDLs usable to open up new dimensions in applications and achieve high market growth, diode laser light sources and beam shaping micro-optics should be designed cohesively. Successful examples of matching of diode laser light sources and beam shaping micro-optics driving new applications are presented.

There are strong demands at the market to increase power and reliability for high power diode laser. In parallel to this the requirements for cooler and package for the high power diode laser increase. Superior heat dissipation capability and low thermal resistance are some of the key attributes for the diode laser package design in the near future. The most common method of removing the large amounts of waste heat in a diode laser is using a micro-channel cooler. However, a microchannel cooler requires water to meet demanding specifications to avoid failures due to corrosion, which increases the overall cost to operate and maintain the laser. We demonstrate advances in a new macro-channel water cooling diode laser which are designed to eliminate the failure mechanisms associated with micro-channel coolers, and enhance the laser heat dissipation and the long-term reliability. For the package adopting the high thermal conductivity material, the maximum output power is 100 W per bar in CW mode. Due to the advantage of compact design, high power, high reliability and fast axis collimation, the new diode laser has the potential to be widely used in many fields, such as pumping solid state laser, hair removal, industry and research.

We wished to construct a prognostic model based on ferroptosis-related genes and to simultaneously evaluate the performance of the prognostic model and analyze differences between high-risk and low-risk groups at all levels. The gene-expression profiles and relevant clinical data of patients with non-small-cell lung cancer (NSCLC) were downloaded from public databases. Differentially expressed genes (DEGs) were obtained by analyzing differences between cancer tissues and paracancerous tissues, and common genes between DEGs and ferroptosis-related genes were identified as candidate ferroptosis-related genes. Next, a risk-score model was constructed using univariate Cox analysis and least absolute shrinkage and selection operator (Lasso) analysis. According to the median risk score, samples were divided into high-risk and low-risk groups, and a series of bioinformatics analyses were conducted to verify the predictive ability of the model. Single-sample gene set enrichment analysis (ssGSEA) was used to investigate differences in immune status between high-risk and low-risk groups, and differences in gene mutations between the two groups were investigated. A risk-score model was constructed based on 21 ferroptosis-related genes. A Kaplan–Meier curve and receiver operating characteristic curve showed that the model had good prediction ability. Univariate and multivariate Cox analyses revealed that ferroptosis-related genes associated with the prognosis may be used as independent prognostic factors for the overall survival time of NSCLC patients. The pathways enriched with DEGs in low-risk and high-risk groups were analyzed, and the enriched pathways were correlated significantly with immunosuppressive status.

To achieve spatial retrieval with compact flexible setup, we present a three-dimensional imaging technique using a dynamic virtual camera to combine multiview acquisition with overlap prelocation, enabling stereo reconstruction across a synthetic field of view.

We present a three-dimensional (3D) imaging system that incorporates a stationary camera and Risley prisms. By planning prism rotation to generate a spatially adaptive virtual camera field, the system allows multiple virtual cameras in the field to capture any object from different perspectives for 3D reconstruction. An automatic virtual camera calibration method based on perspective projection and geometric optics is developed to enable virtual camera field construction and characterization. Moreover, a 3D computational reconstruction framework is proposed for multiview information fusion using the virtual camera field. This framework combines nonlinear distortion correction with epipolar geometry computation to efficiently perform image rectification and stereo matching, which can further facilitate 3D object reconstruction through multiview triangulation. The experiments on synthetic and real data validate the feasibility and flexibility of our 3D imaging technique.

Light detection and ranging (LiDAR) as a significant approach to three-dimensional perception has increasingly suffered from challenges for compact structure, high resolution and strong adaptability. This paper presents a versatile LiDAR system that incorporates multi-beam scanning using Risley prisms and coherent detection based on triangular frequency modulation. By combining Risley-prism-based multi-beam steering model with simultaneous distance and velocity measurements, the LiDAR architecture for three-dimensional imaging is theoretically demonstrated. A unified LiDAR point cloud processing framework is developed, where the multi-mode integrated filtering method is proposed for outlier removal using point cloud characteristics. The coarse-fine coupled strategy is also formulated to combine statistical modeling with iterative optimization for multi-channel point cloud registration. It is experimentally validated that our LiDAR can achieve high-resolution three-dimensional information acquisition against long range, and the proposed point cloud processing technique can fully reconstruct the spatial form of object while preserving sufficient details.

A high peak power annularly-stacked laser diode pump has been designed and manufactured for a solid state laser (SSL), which is constructed by 12 single annular stacks composed of 3-bar laser diode (LD) submodules. High peak power and high wavelength uniformity have been considered. Macro channel cooling has been used during the operation of the annular stacks, at typical coolant flow rate of 2L/min. Heat dissipation and stress of a single annular stack have been simulated by finite element software, which shows high temperature uniformity of 3-bar submodules (plus or minus 0.5℃) and low package stress (11.8MP). The peak power of the annularly stacked laser diode pump has reached 234kW at a peak current of 450A or less. A high uniformity of centroid wavelength (802 plus or minus1nm) with a full width at half maximum (FWHM) of 4nm has been measured. More than 24 million shots have been verified for the 3-bar LD submodules.

Purpose To compare clinicopathologic factors including tumor-node-metastasis (TNM) stage between young and elderly patients with non-small cell lung cancer (NSCLC). Methods This retrospective study compared the following characteristics between 52 young patients with NSCLC (60 years): duration of symptoms before medical consultation, smoking index, family history of cancer, Ki-67 index, and pTNM stage. A binary logistic regression analysis was used to identify factors predictive of greater stage NSCLC (stage III/IV compared to stage I/II) within each age group. Results The incidence of adenocarcinoma was higher in the young than in the elderly (P=0.006). Smoking index (P=0.002) and Ki-67 index (P

Dual-beam transformation systems (dual BTSs) are used to obtain a wide wavelength-locking range for high-power large-smile diode-laser arrays. The collimating residual divergence angle can be reduced from 9 mrad to less than 6.5 mrad using a set of two angled BTSs that are located in front of a diode-laser array with about a 2 µm smile. Due to the reduced collimating residual divergence angle, the external cavity with a set of two angled BTSs and a volume Bragg grating achieved a wide wavelength-locking range for temperatures ranging from 20°C to 30°C. In addition, the side-mode suppression ratio exceeds 30 dB.

Fast imaging tracking technology exhibits attractive application prospects in the emerging fields of target tracking and recognition. Smart and compact tracking model with fast and flexible tracking strategy can play a decisive role in improving system performance. In this paper, an effective imaging tracking model from a target to a rotation Risley prism pair embedded with a camera is derived by the beam vector propagation method. A boresight adjustment strategy using the inverse ray tracing and iterative refinement method is established to accomplish the function of fast locating a target. The influence of system parameters on boresight adjustment accuracy and even the dynamic characteristics of the tracking system are investigated to reveal the coupling mechanisms between prism rotation and imaging feedback. The root-mean-square tracking error is below 4.5 pixels by just once adjustment in the static target experiment, while the error in the dynamic experiment is below 8.5 pixels for a target moving at the speed of 50 mm/s, which validates the feasibility of the proposed method for fast imaging tracking applications.

Passively Q-switched solid-state laser is potentially a very advantageous light source for automotive LiDAR application. The key challenge is the ability of wide temperature range operation. In this work we investigated high-power diode laser bar pumped passively Q-switched Nd:YAG/Cr:YAG solid-state laser with a stable output over a wide temperature range. Firstly we studied the impact of the pump light wavelength and the laser crystal temperature on the pulse energy and threshold, and results showed that to obtain the stable output of a solid-state laser in a wide temperature range, both the diode output and the laser crystal temperature should be stabilized in a reasonable small range. Further we designed and fabricated solid-state laser modules with a single active temperature control for both laser diode and crystal, which had stable pulse energy of millijoules with a pulse width of about 2 ns and a repetition rate of 30 Hz over a wide temperature range from -30 oC to 90 oC.

High-power diode lasers are widely used in solid-state and fiber laser pumping. The spectral power distribution (SPD) of diode lasers should be perfectly matched with the absorption peak of gain materials. Spectral broadening would lead to a low optical-optical efficiency for the pump lasers. In this paper, a mathematical model based on multiple Gaussian functions was introduced to characterize the SPD of high-power diode lasers. The effect of temperature and the distribution on laser spectrum was specially included in this model. Temperature distribution in high-power diode lasers was calculated via an analytical three-dimensional thermal model. The temperature difference within the active region for diode lasers with different package structures and under different heat dissipation conditions was demonstrated. The intrinsic SPD for diode lasers with uniform junction temperature distribution was obtained from the experimental measurements in which a cold pulse current was injected into the diode lasers. SPDs for diode lasers under different injected currents were illustrated by this spectrum model, and compared to the experimental results for model validation. SPDs for the diode lasers with different chip architectures and packaging structures was calculated by coupling the analytical temperature fields into the spectrum model. Laser spectrum was verified to be independent of current density, but mainly depend on the junction temperature distribution in the experiments by comparing the spectra of the epi-up and epi-down packaged F-Mount single-emitters at same injected current.

We have simulated and optimized a conductive cooling structure including the distribution of temperature in active layer, and the deformation of laser to achieve high power operation with low SMILE value. Unlike the traditional conductive cooling structure, our structure improves the heat dissipation efficiency from three aspects: with angle structure in the front of heat sink; double side heat dissipation and without submount packaging technology. In this report, an output power of more than 250W CW from a 4 mm long laser bar with a filling factor of 50% is shown at 240A driving current with a power conversion efficiency of 65%. The thermal rollover of this packaging conductive cooling device can reach 385W at 400A driving current.

Thermomechanical behavior has an important effect on reliability and lifetime of high-power diode lasers (HPDLs). Finite-element analysis (FEA) model and analytical solution model of the conduction-cooled package (CS) HPDL are established to analyze the thermomechanical behavior including normal stress, shearing stress, and displacement in reflowing process and working process. Moreover, in order to simulate and analyze the thermomechanical behavior in total process, reflowing thermal stress and displacement are considered as the residual stress and the initial condition of working process. We find that shearing stress is the origin of other thermomechanical behavior due to coefficient thermal expansion (CTE) mismatch, while both CTE mismatch and temperature gradient cause the thermal stress and displacement in working process. Although thermal stresses and displacement induced in reflowing process are larger than working process, the working process has great impact on smile and causes much worse total smile. The influence of different working temperatures on smile is also studied in total process with analytical solution, FEA, and experiment. For analytical solution, the total smile value is inversely proportional to the working temperature, while for FEA the smile value is proportional to the working temperature and FEA result accords with experimental result.

Multi-dimensional information extraction for objects in restricted-space scenarios plays a pivotal role in flouring fields such as aerospace exploration, smart manufacturing, and biomedical observation. In this paper, we proposed a robust and accurate six-degree-of-freedom pose estimation method based on equivalent virtual cameras, which enables six degrees of freedom (6DoF) reconstruction using rotation averaging and computational imaging. It consists of rotation estimation to extract orientation and translation estimation for position recovery. The former with a feature that a rotating-prism-integrated static camera stares at control points from constrainable view arrays, and the latter with a feature that multiple virtual cameras split from the camera gaze at control points in a one-to-one correspondence. Compared with leading monocular approaches, our architecture achieves accurate measurement despite few control points and large noise. The experimental results show that our architecture achieves 6DoF measurement with means errors better than 0.4 mm and 0.4° competitive to conventional multi-camera vision.

Large smile, the emitters in a laser diode are vertically displaced, is always a big obstacle to affect the directly application of high power laser diode. In this report, a symmetrical structure, that bonding two submounts on the top and bottom of heat sink to control the smile effect by balancing the packaging induced stress, is designed. A cm bar with less than 1 um smile value delivering more than 200W continuous wave (CW) mode output power with power conversion efficiency (PCE) 65% is reported. The lifetime can reach more than 20000 hours. We also report the applications of high power and low smile vertically stacked laser bars, like forming a wider line for glass surface treatment and a rectangular beam for cladding. A 2x14mm2 rectangular beam was built with 32 bars vertical stack to produce 6kW CW mode output power with a beam uniformity of more than 80%.

Numerical and analytical methods are employed to investigate the thermal and fluid flow performance of a microchannel heat sink for cooling a high-power diode laser bar. Heat transfer characteristics and pressure drop in the microchannel under different flow rates are studied. A thermal resistance network, which is proved to have less than 5.4% error, is proposed to characterize the resistance components for the microchannel heat sink. Both numerical modeling and thermal resistance network analysis are verified by experimental results based on the wavelength shift method. Two new heat sinks with more uniform temperature distribution for laser emitters compared with the existing design are presented, and their performance is validated by numerical modeling and spatially resolved spectrum measurements.

A double-wedge prism device has been used in various imaging detection applications due to its high precision and strong anti-disturbance capability. In this paper, a self-adaptation double-wedge prism boresight adjustment principle suitable for both far-field and near-field target tracking is proposed. In order to realize this application, an adaptive variable boresight imaging tracking device is designed specifically. Then a tracking error model is established, and dynamic simulation, error evaluation, and sensitivity analysis are carried out according to the design objective. The experimental results show that the pitch angle deviation and azimuth angle deviation of the device are less than 6', and the blind zone can be eliminated by adding a third wedge prism, thus achieving high-precision boresight adjustment and tracking.

High power QCW diode laser stacks have been widely used in pumping applications for years. Different package structures of diode laser stacks are applied for pumping the cylindrical rod crystal, such as modular G-Stack, horizontal, vertical and annular arrays. Annular array is preferred in pumping of QCW mode with low duty cycle and short pulse width, due to the advantage of compact structural size, uniform light beam distribution and convenient electric connection. However, the development of annular diode laser array using hard solder is difficult because of the complex bonding process of diode laser on annular heatsink with conventional bonding fixture. Furthermore the stress and thermal behavior is yet to be well studied on the annular diode laser array. In this work, a sophisticated annular diode laser array was developed using hard solder. Optimized structure and thermal design were conducted to achieve uniform light beam distribution and good heat dissipation. Stress release structure of diode laser stack is applied to reduce the risk of chip crack and deviation of spatial spectrum. The annular diode laser array consists of 44 bars in a ring, with the peak output power of each bar over 500W. The maximum output power of each bar reaches 673 W.

Heat conduction is of great importance in thermal design for high power diode lasers. In this paper, an analytical, threedimensional, steady-state, multilayered, thermal model for a high power diode laser is derived. The temperature and heat flux distribution are discussed for an epi-down bonded broad-area diode laser, and it is found that heat spreading within laser chip contributes 6.8% to total heat dissipation. Further discussion is carried out on heat flow in the submount to show the submount size requirement for which this model can be used. Simulation result based on finite element method (FEM) is employed to confirm the calculation accuracy from this analytical model.

High power laser diodes have been widely utilized in many fields, like industry, scientific research, military and medical treatment, etc. However, thermal stress induced by packaging process due to CTE-mismatch between chip and heat-sink is the main source causing near-field non-linearity along laser bar (also known as “SMILE”), decreasing the degree of polarization (DoP), broadening spectrum, and degrading the lifetime of laser diode array (LDA). In this paper, the effect of packaging induced thermal stress on high power laser diode arrays was studied theoretically and experimentally. The FEM simulation and photoluminescence (PL) experimental results showed the difference of packaging induced thermal stress based on different packaging structures. Spectrally resolved spectrum of LDA showed the packaging induced stress is highest in the middle and rapidly drops near both ends of laser bar, in agreement with our theoretical simulation, resulting in spectral broadening due to blue shifting the lasing wavelength of the center emitter more than the edge emitters.

A high-side mode suppression ratio (SMSR) and high-stability external-cavity diode laser array employing optical feedback from a volume Bragg grating (VBG) with 15% diffraction efficiency at 976 nm was investigated. Based on the transfer matrix method and on the multimode rate equation, the theoretical model for an external-cavity diode laser at 976 nm was built for different temperature and current values. Both the simulated and the experimental results show that the temperature and the current range of such laser array with a front end reflectivity (R f ) of 0.5% are 10 °C and 15 A broader than that for an external cavity with R f = 2%. As a result, the external-cavity diode laser array at 976 nm with a R f value of 0.5% exhibits a high stability in the temperature range of 15–35 °C and from 15 to 50 A. Moreover, it shows an SMSR higher than 30 dB and a power larger than 33.9 W at 50A.

Based on Snell's law and the constant phase in the front of optical field, a design method of the slow axis collimation lens with variable curvature radius is proposed for semiconductor laser bars. Variable radius of the collimator is designed by the transmission angle, and it is demonstrated that the collimator has good beam collimation ability by material with low refractive index. Resorting to the design thought of finite element method, the surface of the collimator has been divided, and it is feasible to be fabricated. This method is applied as an example in collimation of a 976 nm semiconductor laser bar. 6 mrad divergence angle of collimated beam at slow axis is realized by the designed collimation lens with refraction index of 1.51.

An analytical three-dimensional thermal model is employed to perform the thermal design for the package of high-power single-emitter laser diodes. Thermal design curves for the heat sink and submount are presented in detail, for laser diodes subjected to several convective heat transfer conditions on the bottom of the heat sink. An effective heat spreading angle is proposed to characterize thermal design for the heat sink. A differential heat spreading angle is proposed to clearly manifest heat flow in the packages. Full width and length at 90% energy are introduced to reveal the requirement of submount width and length, respectively. The impact of coefficient of thermal expansion (CTE)-matched sandwiched submount on total heat dissipation is studied. Special discussion is presented for a commercial F-Mount laser diode, and it is found that current heat sink design leads to a 27.4% increase in thermal resistance relative to a free lateral diffusion package.

We present a three-dimensional (3D) computational imaging architecture based on the imaging principle of a dynamic virtual camera, which enables the spatial reconstruction using a single camera and a compact wedge prism device. By rotating the prism for camera boresight adjustment, the proposed system can capture an object from different viewpoints. Each captured image appears to be recorded directly with one virtual camera moving in a certain path, facilitating the computational process for stereo matching and profile reconstruction. The experimental results have demonstrated that our architecture allows a compact and flexible system to achieve 3D imaging performance competitive to conventional stereovision.