Melanoma,characterized by high mortality,rapid development and accompanied with angio-genesis is the most typical malignant tumor in skin cancer.Hence,the detection of blood vessels is of much significanoe.The early v...Melanoma,characterized by high mortality,rapid development and accompanied with angio-genesis is the most typical malignant tumor in skin cancer.Hence,the detection of blood vessels is of much significanoe.The early vascular network has small scale.If we remove the tumor early and biopsy it,it will increase the spread of the cancer cells and infection and bleeding.In this case,we presented a new angiography method.A high-resolution OCT system for noninvasive an-giographic imaging of early skin melanoma-Swept Source Optical Coberence Tomography Angiography(SS-OCTA)is proposed.With a high lateral resolution of 10pm in vrivo tomographic angiography,SS-OCTA is used to image and identify the morphology of the early tumor blood vessels.In addition,a control group experiment is conducted to observe the growth of melanoma in the process of rupture,malormation of micro-vessels.The results of the analysis and statistical test(P<0.05)are statistically signifcant.展开更多
AIM: To compare the ocular fundus features of highly myopic eyes with and without macular Bruch’s membrane(BM) defects and investigate the associations between macular BM defects and other myopic lesions.METHODS: Thi...AIM: To compare the ocular fundus features of highly myopic eyes with and without macular Bruch’s membrane(BM) defects and investigate the associations between macular BM defects and other myopic lesions.METHODS: This retrospective, observational case series included 262 eyes(139 patients) with high myopia(HM) refractive error ≥-6.0 diopters(D) or axial length ≥26.5 mm from March 2019 to December 2019.The patients underwent a comprehensive ophthalmic examination, including sweptsource optical coherence tomography(SS-OCT).The features of macular BM defects and other ocular fundus lesions were examined in OCT images.RESULTS: Totally 51 eyes(19.5%) were detected with macular BM defects, which were characterized by a lack of BM, retinal pigment epithelium(RPE), and an almost complete loss of photoreceptors or choriocapillaris.Eyes with macular BM defects had worse best-corrected visual acuity(BCVA) than those without(P<0.001).Dome-shaped macula(DSM, P=0.042), retinal cysts(P=0.006), choroidal neovascularization(CNV, P<0.001), choroidal defects and abnormality(P=0.003), scleral defects(P=0.015), scleral deformation(P=0.005), posterior staphyloma(P=0.011), and perforating vessels(P<0.001) occurred more frequently in eyes with macular BM defects.In multivariate analysis, the presence of macular BM defects remained the significant association with presence of DSM(P=0.013), scleral defects(P=0.015), posterior staphyloma(P=0.001), perforating vessels(P<0.001) and CNV(P=0.004).CONCLUSION: Macular BM defects has a prevalence of approximately 20% in HM and it has tight association with other myopic fundus lesions.BM might be crucial in the pathogenesis of myopic fundus lesions due to its biomechanical function.A comprehensive understanding of BM’s role is useful for further researches about myopic lesions.展开更多
We demonstrate significantly improved performance of a microwave true time delay line based on an integrated optical frequency comb source. The broadband micro-comb(over 100 nm wide) features a record low free spectra...We demonstrate significantly improved performance of a microwave true time delay line based on an integrated optical frequency comb source. The broadband micro-comb(over 100 nm wide) features a record low free spectral range(FSR) of 49 GHz, resulting in an unprecedented record high channel number(81 over the C band)—the highest number of channels for an integrated comb source used for microwave signal processing. We theoretically analyze the performance of a phased array antenna and show that this large channel count results in a high angular resolution and wide beam-steering tunable range. This demonstrates the feasibility of our approach as a competitive solution toward implementing integrated photonic true time delays in radar and communications systems.展开更多
A frequency and wavelength tunable self-pulsation laser based on DBR laser devices is reported for the first time.This laser generates continuous tunable optical microwave in the range of 1.87-21.81 GHz with 3-dB line...A frequency and wavelength tunable self-pulsation laser based on DBR laser devices is reported for the first time.This laser generates continuous tunable optical microwave in the range of 1.87-21.81 GHz with 3-dB linewidth about 10 MHz by tuning the injection currents on the front and back gain sections,and exhibits wavelength tuning range from 1536.28 to 1538.73 nm by tuning the injection currents on the grating section.展开更多
The spatial orientation of optical radiation sources has long been the hot topic in the aerospace and the military applications.Current researches mainly focus on the high precision orientation on the partial field of...The spatial orientation of optical radiation sources has long been the hot topic in the aerospace and the military applications.Current researches mainly focus on the high precision orientation on the partial field of view.Thus,combination of several partial fields of view is required to achieve orientation when the field of view exceeds 180°,which results in the increase of size,weight,power consumption and the cost.By defining radiation energy and direction of the optical radiation source as a vector and applying the cosine law of radiation and vector theorem,it is shown that the vector can be obtained from unit normal vectors on the three un-coplanar surfaces and from the energy projected by the optical radiation source.Based on this,an orientation method with 360° full field of view by a polyhedron is suggested,the mathematical formula for anti-multipath interference is supposed and the error upper limit is derived.The feasibility and effectiveness of this method are validated by measurements and simulation.An accuracy better than 2.866° and 0.574° is achieved when the ratio of measurement error of energy on arbitrary surface and the true value are 5% and 1%,respectively,given the matrix composed of unit normal vectors on three measurement surfaces is orthogonal.展开更多
Background:To evaluate the effect of orthokeratology on precision of measurements in children using a new swept-source optical coherence tomography(SS-OCT)optical biometer(OA-2000),and agreement between its measuremen...Background:To evaluate the effect of orthokeratology on precision of measurements in children using a new swept-source optical coherence tomography(SS-OCT)optical biometer(OA-2000),and agreement between its measurements and those provided by the commonly used IOLMaster based on partial coherence interferometry(PCI).Methods:This study recruited fifty-one eyes of 51 normal children(8–16 years).An operator took measurements with the two biometers.Then,a second operator took measurements with the SS-OCT biometer.After orthokeratology was performed for one month,the same operators repeated the same procedures.Axial length(AL),mean keratometry(Km)at 2.5 mm and 3.0 mm diameters(Km2.5 and Km3.0),central corneal thickness(CCT),anterior chamber depth(ACD),lens thickness(LT)and corneal diameter(CD)were analyzed.Results:With the SS-OCT optical biometer,the test-retest repeatability of AL measurements was<0.06 mm.For all parameters,the coefficients of variation were<1.23%and the intraclass correlation coefficients were>0.95.The 95%limits of agreement of difference between the two devices for CD parameter were up to 1.53 mm.After orthokeratology,the fluctuation ranges of difference for Km3.0 measurement was 1.11 times higher than before orthokeratology,while the absolute values of difference for AL,Km2.5,ACD and CD measurements were comparable.Conclusions:Before and after orthokeratology,the SS-OCT biometer showed high repeatability and reproducibility for all measurements.Wearing orthokeratology contact lenses affected the agreement between SS-OCT and PCI biometers for Km3.0 measurements.The CD measurement showed poor agreement between the two devices.展开更多
Optical emission spectroscopy（OES）, as a simple in situ method without disturbing the plasma, has been performed for the plasma diagnosis of a 2.45 GHz permanent magnet electron cyclotron resonance（PMECR） ion sour...Optical emission spectroscopy（OES）, as a simple in situ method without disturbing the plasma, has been performed for the plasma diagnosis of a 2.45 GHz permanent magnet electron cyclotron resonance（PMECR） ion source at Peking University（PKU）. A spectrum measurement platform has been set up with the quartz-chamber electron cyclotron resonance（ECR） ion source [Patent Number： ZL 201110026605.4] and experiments were carried out recently. The electron temperature and electron density inside the ECR plasma chamber have been measured with the method of line intensity ratio of noble gas. Hydrogen plasma processes inside the discharge chamber are discussed based on the diagnostic results. What is more, the superiority of the method of line intensity ratio of noble gas is indicated with a comparison to line intensity ratio of hydrogen. Details will be presented in this paper.展开更多
Background:To measure the anterior and posterior segment structural features of acute primary angle-closure(APAC)eyes.Methods:A total of 36 subjects with unilateral APAC were recruited in this study.The ocular biometr...Background:To measure the anterior and posterior segment structural features of acute primary angle-closure(APAC)eyes.Methods:A total of 36 subjects with unilateral APAC were recruited in this study.The ocular biometric characteristics were measured by anterior segment optical coherence tomography(AS-OCT)and swept source optical coherence tomography(SS-OCT),respectively at baseline,2 weeks,and 1 month after surgical intervention.Results:At baseline,when compared with the fellow eyes,APAC-affected eyes showed significantly greater corneal thickness(P=0.004),shallower anterior chamber depth(ACD)(P<0.001),smaller anterior chamber area(ACA)(P=0.013),angle opening distance at 750μm from the scleral spur(AOD750)(P=0.002),trabecular-iris space area at 750μm from the scleral spur(TISA750)(P=0.033),angle recess area(ARA)(P=0.014),and iris area(IARE)(P=0.003),less iris curvature(ICURVE)(P=0.003),and larger lens vault(LV)(P=0.030).After intervention,the corneal thickness was significantly decreased at 1 month(P<0.001),while ACD,ACA,and AOD750 were significantly increased at 2 weeks and 1 month(all P<0.017).Changes in ACD were correlated with decreasing LV(P<0.05).The posterior segment parameters did not change over the 4-week period.Conclusions:When compared with the fellow eyes,APAC-affected eyes had greater corneal thickness,shallower anterior chamber,narrower angle,less ICURVE,and larger LV.After intervention,the corneal thickness was decreased,while the shallower anterior chamber was relieved to some extent.展开更多
Optical frequency combs(OFCs)are highly promising candidates as multichannel light sources for photonic integrated circuits(PICs).We present a tunable on-chip OFC source based on quantum dot collidingpulse mode-locked...Optical frequency combs(OFCs)are highly promising candidates as multichannel light sources for photonic integrated circuits(PICs).We present a tunable on-chip OFC source based on quantum dot collidingpulse mode-locked lasers(QD-CPMLs),capable of generating both amplitude-modulated(AM)and frequencymodulated(FM)combs through external-cavity locking.A free-running fourth-order QD-CPML with a 100 GHz repetition rate is demonstrated to produce FM and AM combs under different bias conditions,achieving an ultra-wide comb with a 3-dB bandwidth of 1.8 THz and a 10-dB bandwidth of 2.5 THz.By leveraging externalcavity locking,the modulation dynamics of the comb are finely tuned,significantly expanding the AM comb range while reducing pulse width and chirp.The shortest pulse width achieved is 0.6 ps,with a minimum time-bandwidth product of 0.33,approaching the transform limit for hyperbolic secant pulses.The near-zero linewidth enhancement factor of the QD-CPML effectively suppresses coherence collapse under optical feedback,whereas its low group velocity dispersion facilitates the generation of narrow pulses and broad bandwidths.The ability to dynamically control AM and FM comb regions through external-cavity locking represents an innovative strategy for tunable OFC generation,offering potential for applications in sensing,spectroscopy,and optical communications within PICs.展开更多
Silicon photonics(SiPh)technology has become a key platform for developing photonic integrated circuits due to its CMOS compatibility and scalable manufacturing.However,integrating efficient on-chip optical sources an...Silicon photonics(SiPh)technology has become a key platform for developing photonic integrated circuits due to its CMOS compatibility and scalable manufacturing.However,integrating efficient on-chip optical sources and in-line amplifiers remains challenging due to silicon’s indirect bandgap.In this study,we developed prefabricated standardized InAs/GaAs quantum-dot(QD)active devices optimized for micro-transfer printing and successfully integrated them on SiPh integrated circuits.By transfer-printing standardized QD devices onto specific regions of the SiPh chip,we realized O-band semiconductor optical amplifiers(SOAs),distributed feedback(DFB)lasers,and widely tunable lasers(TLs).The SOAs reached an on-chip gain of 7.5 dB at 1299 nm and maintained stable performance across a wide input power range.The integrated DFB lasers achieved waveguide(WG)-coupled output powers of up to 19.7 mW,with a side-mode suppression ratio(SMSR)of 33.3 dB,and demonstrated notable robustness against optical feedback,supporting error-free data rates of 30 Gbps without additional isolators.Meanwhile,the TLs demonstrated a wavelength tuning range exceeding 35 nm,and a WG-coupled output power greater than 3 m W.The micro-transfer printing approach effectively decouples the fabrication of non-native devices from the SiPh process,allowing back-end integration of the Ⅲ–Ⅴ devices.Our approach offers a viable path toward fully integrated Ⅲ–Ⅴ/ SiPh platforms capable of supporting high-speed,high-capacity communication.展开更多
Microwave photonics(MWP)represents a significant optical signal processing system,standing at the confluence of microwave engineering and photonics.It presents a promising way for meeting the growing demands of contem...Microwave photonics(MWP)represents a significant optical signal processing system,standing at the confluence of microwave engineering and photonics.It presents a promising way for meeting the growing demands of contemporary communication systems,radar,sensing,and signal processing.Driving the rapid advancement of MWP are pivotal technologies such as optical frequency combs,photonic integrated circuits,and advanced modulation formats.The integration of photonic integrated circuit technology with hybrid integration techniques holds the promise of realizing MWP systems on a single chip,while comb shaping technology endows MWP systems with programmable and reconfigurable capabilities.In this paper,we present a review of our recent research,which focused on exploring the full spectrum of potential applications for quantum dash lasers in MWP systems.Leveraging principles of finite impulse response filters,our MWP system not only facilitates conventional filtering but also enables instantaneous frequency measurement and waveform generation.A distinguishing feature of MWP filters is their uniform delay.After converting it into a uniform phase difference,it underpins the development of MWP-based phase antenna array systems.Furthermore,this uniform delay finds application in time-interleaved photonic analog-to-digital conversion.展开更多
A quartz-chamber 2.45 GHz electron cyclotron resonance ion source(ECRIS) was designed for diagnostic purposes at Peking University [Patent Number: ZL 201110026605.4]. This ion source can produce a maximum 84 m A hydro...A quartz-chamber 2.45 GHz electron cyclotron resonance ion source(ECRIS) was designed for diagnostic purposes at Peking University [Patent Number: ZL 201110026605.4]. This ion source can produce a maximum 84 m A hydrogen ion beam at 50 k V with a duty factor of 10%. The root-mean-square(RMS) emittance of this beam is less than 0.12π mm mrad. In our initial work,the electron temperature and electron density inside the plasma chamber had been measured with the line intensity ratio of noble gases. Based on these results, the atomic and molecular emission spectra of hydrogen were applied to determine the dissociation degree of hydrogen and the vibrational temperature of hydrogen molecules in the ground state, respectively. Measurements were performed at gas pressures from 4×10^(-4) to 1×10^(-3) Pa and at input peak RF power ranging from 1000 to 1800 W. The dissociation degree of hydrogen in the range of 0.5%-10% and the vibrational temperature of hydrogen molecules in the ground state in the range of 3500-8500 K were obtained. The plasma processes inside this ECRIS chamber were discussed based on these results.展开更多
基金supported by the Jiangsu Province Science Fund for Distinguished Young Scholars(BK20060010)the Frontier Science Research project of the Chinese Academy of Sciences(QYZDBS-SWJSC03)+2 种基金the National Natural Science Foundation of China(61675226)the National Key R&D Program of China(2017YFC0108200,2017YFB0403700)the Jiangsu Province Key R&D Program(BE2018667).
文摘Melanoma,characterized by high mortality,rapid development and accompanied with angio-genesis is the most typical malignant tumor in skin cancer.Hence,the detection of blood vessels is of much significanoe.The early vascular network has small scale.If we remove the tumor early and biopsy it,it will increase the spread of the cancer cells and infection and bleeding.In this case,we presented a new angiography method.A high-resolution OCT system for noninvasive an-giographic imaging of early skin melanoma-Swept Source Optical Coberence Tomography Angiography(SS-OCTA)is proposed.With a high lateral resolution of 10pm in vrivo tomographic angiography,SS-OCTA is used to image and identify the morphology of the early tumor blood vessels.In addition,a control group experiment is conducted to observe the growth of melanoma in the process of rupture,malormation of micro-vessels.The results of the analysis and statistical test(P<0.05)are statistically signifcant.
文摘AIM: To compare the ocular fundus features of highly myopic eyes with and without macular Bruch’s membrane(BM) defects and investigate the associations between macular BM defects and other myopic lesions.METHODS: This retrospective, observational case series included 262 eyes(139 patients) with high myopia(HM) refractive error ≥-6.0 diopters(D) or axial length ≥26.5 mm from March 2019 to December 2019.The patients underwent a comprehensive ophthalmic examination, including sweptsource optical coherence tomography(SS-OCT).The features of macular BM defects and other ocular fundus lesions were examined in OCT images.RESULTS: Totally 51 eyes(19.5%) were detected with macular BM defects, which were characterized by a lack of BM, retinal pigment epithelium(RPE), and an almost complete loss of photoreceptors or choriocapillaris.Eyes with macular BM defects had worse best-corrected visual acuity(BCVA) than those without(P<0.001).Dome-shaped macula(DSM, P=0.042), retinal cysts(P=0.006), choroidal neovascularization(CNV, P<0.001), choroidal defects and abnormality(P=0.003), scleral defects(P=0.015), scleral deformation(P=0.005), posterior staphyloma(P=0.011), and perforating vessels(P<0.001) occurred more frequently in eyes with macular BM defects.In multivariate analysis, the presence of macular BM defects remained the significant association with presence of DSM(P=0.013), scleral defects(P=0.015), posterior staphyloma(P=0.001), perforating vessels(P<0.001) and CNV(P=0.004).CONCLUSION: Macular BM defects has a prevalence of approximately 20% in HM and it has tight association with other myopic fundus lesions.BM might be crucial in the pathogenesis of myopic fundus lesions due to its biomechanical function.A comprehensive understanding of BM’s role is useful for further researches about myopic lesions.
基金Australian Research Council(ARC)Discovery Projects Program(DP150104327)Strategic,Discovery and Acceleration Grants Schemes of Natural Sciences and Engineering Research Council of Canada(NSERC)+4 种基金MESI PSR-SIIRI Initiative in QuebecCanada Research Chairs ProgramITMO Fellowship and Professorship Program of the Government of the Russian Federation(074-U 01)1000 Talents Sichuan Program in ChinaStrategic Priority Research Program of the Chinese Academy of Sciences(CAS)(XDB24030000)
文摘We demonstrate significantly improved performance of a microwave true time delay line based on an integrated optical frequency comb source. The broadband micro-comb(over 100 nm wide) features a record low free spectral range(FSR) of 49 GHz, resulting in an unprecedented record high channel number(81 over the C band)—the highest number of channels for an integrated comb source used for microwave signal processing. We theoretically analyze the performance of a phased array antenna and show that this large channel count results in a high angular resolution and wide beam-steering tunable range. This demonstrates the feasibility of our approach as a competitive solution toward implementing integrated photonic true time delays in radar and communications systems.
基金Project supported by the National High Technology Research and Development Program of China(Nos.2006AA01Z256, 2007AA03Z419,2007AA03Z417)the State Key Development Program for Basic Research of China(Nos.2006CB604901, 2006CB604902)the National Natural Science Foundation of China(Nos.90401025,60736036,60706009,60777021).
文摘A frequency and wavelength tunable self-pulsation laser based on DBR laser devices is reported for the first time.This laser generates continuous tunable optical microwave in the range of 1.87-21.81 GHz with 3-dB linewidth about 10 MHz by tuning the injection currents on the front and back gain sections,and exhibits wavelength tuning range from 1536.28 to 1538.73 nm by tuning the injection currents on the grating section.
文摘The spatial orientation of optical radiation sources has long been the hot topic in the aerospace and the military applications.Current researches mainly focus on the high precision orientation on the partial field of view.Thus,combination of several partial fields of view is required to achieve orientation when the field of view exceeds 180°,which results in the increase of size,weight,power consumption and the cost.By defining radiation energy and direction of the optical radiation source as a vector and applying the cosine law of radiation and vector theorem,it is shown that the vector can be obtained from unit normal vectors on the three un-coplanar surfaces and from the energy projected by the optical radiation source.Based on this,an orientation method with 360° full field of view by a polyhedron is suggested,the mathematical formula for anti-multipath interference is supposed and the error upper limit is derived.The feasibility and effectiveness of this method are validated by measurements and simulation.An accuracy better than 2.866° and 0.574° is achieved when the ratio of measurement error of energy on arbitrary surface and the true value are 5% and 1%,respectively,given the matrix composed of unit normal vectors on three measurement surfaces is orthogonal.
基金This work was supported in part by the Foundation of Wenzhou City Science&Technology Bureau(Y20180174)Medical and Health Science and Technology Program of Zhejiang Province(2019KY111)+3 种基金Zhejiang Provincial Key Research and Development Program(2018C03012)Zhejiang Provincial High-level Talents Program(2017-102)The funders had no role in the study design,data collection and analysis,decision to publish,or preparation of the manuscriptThe contribution of G.B.Bietti Foundation IRCCS was supported by the Italian Ministry of Health and Fondazione Roma.
文摘Background:To evaluate the effect of orthokeratology on precision of measurements in children using a new swept-source optical coherence tomography(SS-OCT)optical biometer(OA-2000),and agreement between its measurements and those provided by the commonly used IOLMaster based on partial coherence interferometry(PCI).Methods:This study recruited fifty-one eyes of 51 normal children(8–16 years).An operator took measurements with the two biometers.Then,a second operator took measurements with the SS-OCT biometer.After orthokeratology was performed for one month,the same operators repeated the same procedures.Axial length(AL),mean keratometry(Km)at 2.5 mm and 3.0 mm diameters(Km2.5 and Km3.0),central corneal thickness(CCT),anterior chamber depth(ACD),lens thickness(LT)and corneal diameter(CD)were analyzed.Results:With the SS-OCT optical biometer,the test-retest repeatability of AL measurements was<0.06 mm.For all parameters,the coefficients of variation were<1.23%and the intraclass correlation coefficients were>0.95.The 95%limits of agreement of difference between the two devices for CD parameter were up to 1.53 mm.After orthokeratology,the fluctuation ranges of difference for Km3.0 measurement was 1.11 times higher than before orthokeratology,while the absolute values of difference for AL,Km2.5,ACD and CD measurements were comparable.Conclusions:Before and after orthokeratology,the SS-OCT biometer showed high repeatability and reproducibility for all measurements.Wearing orthokeratology contact lenses affected the agreement between SS-OCT and PCI biometers for Km3.0 measurements.The CD measurement showed poor agreement between the two devices.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11175009 and 11575013)
文摘Optical emission spectroscopy（OES）, as a simple in situ method without disturbing the plasma, has been performed for the plasma diagnosis of a 2.45 GHz permanent magnet electron cyclotron resonance（PMECR） ion source at Peking University（PKU）. A spectrum measurement platform has been set up with the quartz-chamber electron cyclotron resonance（ECR） ion source [Patent Number： ZL 201110026605.4] and experiments were carried out recently. The electron temperature and electron density inside the ECR plasma chamber have been measured with the method of line intensity ratio of noble gas. Hydrogen plasma processes inside the discharge chamber are discussed based on the diagnostic results. What is more, the superiority of the method of line intensity ratio of noble gas is indicated with a comparison to line intensity ratio of hydrogen. Details will be presented in this paper.
基金The study was funded by Science and Technology Program of Guangzhou,China(201803010066)the National Natural Science Foundation of China(82000890)Young Talents’Science and Technology Innovation Project of Hainan Association for Science and Technology(QCXM202020).
文摘Background:To measure the anterior and posterior segment structural features of acute primary angle-closure(APAC)eyes.Methods:A total of 36 subjects with unilateral APAC were recruited in this study.The ocular biometric characteristics were measured by anterior segment optical coherence tomography(AS-OCT)and swept source optical coherence tomography(SS-OCT),respectively at baseline,2 weeks,and 1 month after surgical intervention.Results:At baseline,when compared with the fellow eyes,APAC-affected eyes showed significantly greater corneal thickness(P=0.004),shallower anterior chamber depth(ACD)(P<0.001),smaller anterior chamber area(ACA)(P=0.013),angle opening distance at 750μm from the scleral spur(AOD750)(P=0.002),trabecular-iris space area at 750μm from the scleral spur(TISA750)(P=0.033),angle recess area(ARA)(P=0.014),and iris area(IARE)(P=0.003),less iris curvature(ICURVE)(P=0.003),and larger lens vault(LV)(P=0.030).After intervention,the corneal thickness was significantly decreased at 1 month(P<0.001),while ACD,ACA,and AOD750 were significantly increased at 2 weeks and 1 month(all P<0.017).Changes in ACD were correlated with decreasing LV(P<0.05).The posterior segment parameters did not change over the 4-week period.Conclusions:When compared with the fellow eyes,APAC-affected eyes had greater corneal thickness,shallower anterior chamber,narrower angle,less ICURVE,and larger LV.After intervention,the corneal thickness was decreased,while the shallower anterior chamber was relieved to some extent.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFB2803600)the National Natural Science Foundation of China(Grant Nos.62204072,62334013,and U22A2093)+3 种基金the Basic and Applied Basic Research Foundation of Guangdong Province(Grant Nos.2021A1515110076 and 2023A1515012304)the Shenzhen Science and Technology Innovation Program(Grant Nos.GXWD20220811163623002,RCBS20210609103824050,JCYJ20240813104819027,and KJZD20240903101100002)the Research Fund of the National Key Laboratory of Laser Spatial Information(Grant No.LSI2025WDZC03)the Open Research Program of the State Key Laboratory of Radio Frequency Heterogeneous Integration(Grant No.KF2025010).
文摘Optical frequency combs(OFCs)are highly promising candidates as multichannel light sources for photonic integrated circuits(PICs).We present a tunable on-chip OFC source based on quantum dot collidingpulse mode-locked lasers(QD-CPMLs),capable of generating both amplitude-modulated(AM)and frequencymodulated(FM)combs through external-cavity locking.A free-running fourth-order QD-CPML with a 100 GHz repetition rate is demonstrated to produce FM and AM combs under different bias conditions,achieving an ultra-wide comb with a 3-dB bandwidth of 1.8 THz and a 10-dB bandwidth of 2.5 THz.By leveraging externalcavity locking,the modulation dynamics of the comb are finely tuned,significantly expanding the AM comb range while reducing pulse width and chirp.The shortest pulse width achieved is 0.6 ps,with a minimum time-bandwidth product of 0.33,approaching the transform limit for hyperbolic secant pulses.The near-zero linewidth enhancement factor of the QD-CPML effectively suppresses coherence collapse under optical feedback,whereas its low group velocity dispersion facilitates the generation of narrow pulses and broad bandwidths.The ability to dynamically control AM and FM comb regions through external-cavity locking represents an innovative strategy for tunable OFC generation,offering potential for applications in sensing,spectroscopy,and optical communications within PICs.
基金European Union(CALADAN)(825453)Dutch Growth Fund PhotonDelta project。
文摘Silicon photonics(SiPh)technology has become a key platform for developing photonic integrated circuits due to its CMOS compatibility and scalable manufacturing.However,integrating efficient on-chip optical sources and in-line amplifiers remains challenging due to silicon’s indirect bandgap.In this study,we developed prefabricated standardized InAs/GaAs quantum-dot(QD)active devices optimized for micro-transfer printing and successfully integrated them on SiPh integrated circuits.By transfer-printing standardized QD devices onto specific regions of the SiPh chip,we realized O-band semiconductor optical amplifiers(SOAs),distributed feedback(DFB)lasers,and widely tunable lasers(TLs).The SOAs reached an on-chip gain of 7.5 dB at 1299 nm and maintained stable performance across a wide input power range.The integrated DFB lasers achieved waveguide(WG)-coupled output powers of up to 19.7 mW,with a side-mode suppression ratio(SMSR)of 33.3 dB,and demonstrated notable robustness against optical feedback,supporting error-free data rates of 30 Gbps without additional isolators.Meanwhile,the TLs demonstrated a wavelength tuning range exceeding 35 nm,and a WG-coupled output power greater than 3 m W.The micro-transfer printing approach effectively decouples the fabrication of non-native devices from the SiPh process,allowing back-end integration of the Ⅲ–Ⅴ devices.Our approach offers a viable path toward fully integrated Ⅲ–Ⅴ/ SiPh platforms capable of supporting high-speed,high-capacity communication.
基金supported by the National Research Council Canada(Grant Nos.HTSN-206 and HTSN-245)by the Natural Sciences and Engineering Research Council of Canada.
文摘Microwave photonics(MWP)represents a significant optical signal processing system,standing at the confluence of microwave engineering and photonics.It presents a promising way for meeting the growing demands of contemporary communication systems,radar,sensing,and signal processing.Driving the rapid advancement of MWP are pivotal technologies such as optical frequency combs,photonic integrated circuits,and advanced modulation formats.The integration of photonic integrated circuit technology with hybrid integration techniques holds the promise of realizing MWP systems on a single chip,while comb shaping technology endows MWP systems with programmable and reconfigurable capabilities.In this paper,we present a review of our recent research,which focused on exploring the full spectrum of potential applications for quantum dash lasers in MWP systems.Leveraging principles of finite impulse response filters,our MWP system not only facilitates conventional filtering but also enables instantaneous frequency measurement and waveform generation.A distinguishing feature of MWP filters is their uniform delay.After converting it into a uniform phase difference,it underpins the development of MWP-based phase antenna array systems.Furthermore,this uniform delay finds application in time-interleaved photonic analog-to-digital conversion.
基金supported by the National Natural Science Foundation of China(Grant Nos.11775007,and 11575013)The support from State Key Laboratory of Nuclear Physics and Technology,Peking University is appreciated
文摘A quartz-chamber 2.45 GHz electron cyclotron resonance ion source(ECRIS) was designed for diagnostic purposes at Peking University [Patent Number: ZL 201110026605.4]. This ion source can produce a maximum 84 m A hydrogen ion beam at 50 k V with a duty factor of 10%. The root-mean-square(RMS) emittance of this beam is less than 0.12π mm mrad. In our initial work,the electron temperature and electron density inside the plasma chamber had been measured with the line intensity ratio of noble gases. Based on these results, the atomic and molecular emission spectra of hydrogen were applied to determine the dissociation degree of hydrogen and the vibrational temperature of hydrogen molecules in the ground state, respectively. Measurements were performed at gas pressures from 4×10^(-4) to 1×10^(-3) Pa and at input peak RF power ranging from 1000 to 1800 W. The dissociation degree of hydrogen in the range of 0.5%-10% and the vibrational temperature of hydrogen molecules in the ground state in the range of 3500-8500 K were obtained. The plasma processes inside this ECRIS chamber were discussed based on these results.
