Recent theoretical verification of self-similar and dissipative pure-quartic solitons(PQSs)emphasized the similarity between PQS lasers and conventional fiber lasers,but the unique equilibrium mechanism hinders the fo...Recent theoretical verification of self-similar and dissipative pure-quartic solitons(PQSs)emphasized the similarity between PQS lasers and conventional fiber lasers,but the unique equilibrium mechanism hinders the formation of PQS molecules in normal fourth-order dispersion(FOD)regimes.In this paper,we investigated the effect of filters on shaping PQSs in normal FOD based on a passively mode-locked fiber laser model.A bandpass filter eliminates the time pedestal of dissipative PQSs,thus realizing a multi-pulsing state.When the filter bandwidth is appropriate,the effective spectral filtering effect can lower the pulse splitting threshold and enable the coherent restoration from chaotic PQSs to PQS molecules.Additionally,changing the central wavelength of the filter can generate PQSs and PQS molecules with asymmetric intensity distributions.These results are important guides for the manipulation of PQSs and the construction of high repetition-frequency fiber lasers.展开更多
We propose and demonstrate an alternative method for spectral filtering and frequency stabilization of both 780-nm and 960-nm lasers using a high-finesse length-tunable cavity(HFLTC).Firstly,the length of HFLTC is sta...We propose and demonstrate an alternative method for spectral filtering and frequency stabilization of both 780-nm and 960-nm lasers using a high-finesse length-tunable cavity(HFLTC).Firstly,the length of HFLTC is stabilized to a commercial frequency reference.Then,the two lasers are locked to this HFLTC using the Pound–Drever–Hall(PDH)method which can narrow the linewidths and stabilize the frequencies of both lasers simultaneously.Finally,the transmitted lasers of HFLTC with each power up to about 100μW,which act as seed lasers,are amplified using the injection locking method for single-atom Rydberg excitation.The linewidths of obtained lasers are narrowed to be less than 1 k Hz,meanwhile the obtained lasers'phase noise around 750 k Hz are suppressed about 30 d B.With the spectrally filtered lasers,we demonstrate a Rabi oscillation between the ground state and Rydberg state of single-atoms in an optical trap tweezer with a decay time of(67±37)μs,which is almost not affected by laser phase noise.We found that the maximum short-term laser frequency fluctuation of a single excitation lasers is at~3.3 k Hz and the maximum long-term laser frequency drift of a single laser is~46 k Hz during one month.Our work develops a stable and repeatable method to provide multiple laser sources of ultra-low phase noise,narrow linewidth,and excellent frequency stability,which is essential for high precision atomic experiments,such as neutral atom quantum computing,quantum simulation,quantum metrology,and so on.展开更多
An optical modulation format generation scheme based on spectral filtering and frequency-to-time mapping is experimentally demonstrated. Many modulation formats with continuously adjustable duty radio and bit rate can...An optical modulation format generation scheme based on spectral filtering and frequency-to-time mapping is experimentally demonstrated. Many modulation formats with continuously adjustable duty radio and bit rate can be formed by changing the dispersion of dispersion element and the bandwidth of shaped spectrum in this scheme. In the experiment, non-return-to-zero(NRZ) signal with bit rate of 29.41 Gbit/s and 1/2 duty ratio return-to-zero(RZ) signal with bit rate of 13.51 Gbit/s are obtained. The maximum bit rate of modulation format signal is also analyzed.展开更多
According to electro-optical sampling theory, we propose a new method to detect the spatiotemporal field of a single- shot terahertz pulse by spectral holography for the first time. The single-shot terahertz pulse is ...According to electro-optical sampling theory, we propose a new method to detect the spatiotemporal field of a single- shot terahertz pulse by spectral holography for the first time. The single-shot terahertz pulse is coupled into a broadened chirped femtosecond pulse according to electro-optical sampling theory in the detecting system. Then the reference wave and the signal wave are split by Dammann grating and spread into the interference band-pass filter. The filtered sub-waves are at different central-frequencies because of the different incident angles. These sub-waves at different central-frequencies interfere to form sub-holograms, which are recorded in a single frame of a charge coupled device （CCD）. The sub-holograms are numerically processed, and the spatiotemporal field distribution of the original terahertz pulse is reconstructed. The computer simulations verify the feasibility of the proposed method.展开更多
We demonstrate a highly compact third-order elliptical micro-ring add-drop filter based on a silicon-on-insulator wafer. The elliptical micro-ring resonator has a major radius of 6μm （minor radius of 4.112μm） and ...We demonstrate a highly compact third-order elliptical micro-ring add-drop filter based on a silicon-on-insulator wafer. The elliptical micro-ring resonator has a major radius of 6μm （minor radius of 4.112μm） and a large free spectral range of 18 nm. Experimental results show a box-like channel dropping response, which has a 3 dB bandwidth of -2.7nm, high out-of-band signal rejection of around 40dB and a very low drop loss （〈0.5dB）. Simulation agrees well with the experiments. The footprint of the whole chip is only 0.0003mm2.展开更多
Dark soliton solutions of the one-dimensional complex Ginzburg-Landau equation （CGLE） are analysed for the case of normal group-velocity dispersion. The CGLE can be transformed to the nonlinear Schrodinger equation ...Dark soliton solutions of the one-dimensional complex Ginzburg-Landau equation （CGLE） are analysed for the case of normal group-velocity dispersion. The CGLE can be transformed to the nonlinear Schrodinger equation （NLSE） with perturbation terms under some practical conditions. The main properties of dark solitons are analysed by applying the direct perturbation theory of the NLSE. The results obtained may be helpful for the research on the optical soliton transmission system.展开更多
An experiment was carried out to examine the effects of light quality on the growth and development of antirrhinum under three different temperatures 19℃, 24℃ and 27℃ in glasshouses. Five different colour filters (...An experiment was carried out to examine the effects of light quality on the growth and development of antirrhinum under three different temperatures 19℃, 24℃ and 27℃ in glasshouses. Five different colour filters (i.e. 'Red absorbing', 'Blue absorbing', 'Blue and Red absorbing' and two 'partially Blue absorbing' materials) were tested, with one clear polythene as a control. Plant height, internode length and leaf area were significantly affected by the spectral filters as well as the temperature.Analysis of color filter's effect on presumed photoreceptors to exist indicated that antirrhinum plant height was regulated by the action of a blue acting photoreceptor (BAP) and not the phytochrome. There was no evidence for an effect ofphytochrome or BAP on time to flowering, however, increasing temperature levels effectively decreased the time to flowering. To predict the effects of different spectral qualities and temperature, simple models were created from data on plant height, internode length and time to flowering. These models were then applied to simulate the potential benefits of spectral filters and temperature in manipulation of growth control and flowering in antirrhinum.展开更多
Xiao-Xu-Ming decoction（XXMD） was a traditional Chinese prescription and first recorded in ＂Bei Ji Qian Jin Yao Fang＂.It has been widely used to treat theoplegia and the sequel of theoplegia in China.In the present...Xiao-Xu-Ming decoction（XXMD） was a traditional Chinese prescription and first recorded in ＂Bei Ji Qian Jin Yao Fang＂.It has been widely used to treat theoplegia and the sequel of theoplegia in China.In the present work,high-performance liquid chromatography coupled with high resolution mass spectrometry（HPLC-HRMS） combined with the mass spectral tree similarity filter technique（MTSF）was used to rapidly discover and identify the compounds of the active fraction of XXMD.A total of 3362 compounds were automatically detected by HPLC-HRMS,and final 68 compounds were identified in the active fraction of XXMD.including 14 templated compounds（reference compounds）,50 related compounds fished by MTSF technique,and 4 unrelated compounds identified by manual method.This study successfully applied MTSF technology for the first time to discover and identify the components of Chinese prescription.The results demonstrated that MTSF technique should be useful to the discovery and identification of compounds in Chinese prescription.This study also proved that MTSF can be applied to the targeted phytochemical separation.展开更多
Associated with ITU-T G.719,a post-processing method in frequency domain for enhancing the perceptual quality of the decoded transient audio is proposed only to the audio decoder with no side information from the enco...Associated with ITU-T G.719,a post-processing method in frequency domain for enhancing the perceptual quality of the decoded transient audio is proposed only to the audio decoder with no side information from the encoder.The proposed post-filter is used to filter the frequency coefficients of the decoded transient frame and consists of a short-term post-filter and a spectral tilt compensation filter which are derived from linear predictive coding（LPC） predictor based on the discrete cosine transform（DCT） coefficients of the decoded transient frame.As a result,the post-filter in frequency domain shapes the temporal noise in time domain and controls the pre-echo noise effectively while enhancing the transient perception.Listening test results show that the preferring ratio of the post-processed transient signal is higher than that of the original decoded signal at a low bit rate of 32 kbit/s in G.719 and the post-processing module brings a complexity of 12.399 WMOPS to the decoder.展开更多
Transparent electro-optic(EO)oxide ceramics are known for their rapid EO effects.EO ceramics have several advantages over single-crystals,including variable size and shape,controllable chemical composition,superior me...Transparent electro-optic(EO)oxide ceramics are known for their rapid EO effects.EO ceramics have several advantages over single-crystals,including variable size and shape,controllable chemical composition,superior mechanical properties,and low cost.Synthesis of high-performance transparent EO ceramics requires high purity of raw materials,high density,homogeneous composition,uniform grain size,and relatively wide bandgap.Powder synthesis and sintering are two of the critical steps involved in the fabrication of highly transparent EO ceramics.Using high-activity precursor powders has been effective in fabricating high-density ceramics that demonstrate excellent EO performance.The sintering process plays a crucial role in achieving this result,and currently,there are several sintering methods available for producing high-density ceramics,including hot-pressing,hot isostatic pressing,and spark plasma sintering.This review summarizes the recent progress in materials and processes used to develop transparent EO ceramics,including those based on lead zirconate titanate,lead magnesium niobate-lead titanate,and lead-free potassium sodium niobate.In addition,several novel applications of transparent EO ceramics,including light shutters,spectral filters,optical memory,as well as image storage and displays are reviewed.In the end,the review concludes with a discussion of future trends and perspectives.展开更多
With the development of high-volume manufacturing for very-large-scale integrated circuits,the purity of the light source in the extreme ultraviolet lithography(EUVL)system needs to fulfil extreme requirements in orde...With the development of high-volume manufacturing for very-large-scale integrated circuits,the purity of the light source in the extreme ultraviolet lithography(EUVL)system needs to fulfil extreme requirements in order to avoid thermal effect,optical distortion and critical dimension errors caused by out-of-band radiations.This paper reviews the key technologies and developments of the spectral purity systems for both a free-standing system and a built-in system integrated with the collector.The main challenges and developing trends are also discussed,with a view towards practical applications for further improvement.Designing and manufacturing spectral purity systems for EUVL is not a single task;rather,it requires systematic considerations for all relevant modules.Moreover,the requirement of spectral purity filters drives the innovation in filtering technologies,optical micromachining and advanced metrology.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.62175116)。
文摘Recent theoretical verification of self-similar and dissipative pure-quartic solitons(PQSs)emphasized the similarity between PQS lasers and conventional fiber lasers,but the unique equilibrium mechanism hinders the formation of PQS molecules in normal fourth-order dispersion(FOD)regimes.In this paper,we investigated the effect of filters on shaping PQSs in normal FOD based on a passively mode-locked fiber laser model.A bandpass filter eliminates the time pedestal of dissipative PQSs,thus realizing a multi-pulsing state.When the filter bandwidth is appropriate,the effective spectral filtering effect can lower the pulse splitting threshold and enable the coherent restoration from chaotic PQSs to PQS molecules.Additionally,changing the central wavelength of the filter can generate PQSs and PQS molecules with asymmetric intensity distributions.These results are important guides for the manipulation of PQSs and the construction of high repetition-frequency fiber lasers.
基金National Key Research and Development Program of China(Grant No.2016YFA0302800)the National Natural Science Foundation of China(Grant Nos.U20A2074 and 12074391)+2 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB 21010100)the Youth Innovation Promotion Association of Chinese Academy of Sciences(Grant No.2017378)K.C.Wong Education Foundation(Grant No.GJTD-2019-15)。
文摘We propose and demonstrate an alternative method for spectral filtering and frequency stabilization of both 780-nm and 960-nm lasers using a high-finesse length-tunable cavity(HFLTC).Firstly,the length of HFLTC is stabilized to a commercial frequency reference.Then,the two lasers are locked to this HFLTC using the Pound–Drever–Hall(PDH)method which can narrow the linewidths and stabilize the frequencies of both lasers simultaneously.Finally,the transmitted lasers of HFLTC with each power up to about 100μW,which act as seed lasers,are amplified using the injection locking method for single-atom Rydberg excitation.The linewidths of obtained lasers are narrowed to be less than 1 k Hz,meanwhile the obtained lasers'phase noise around 750 k Hz are suppressed about 30 d B.With the spectrally filtered lasers,we demonstrate a Rabi oscillation between the ground state and Rydberg state of single-atoms in an optical trap tweezer with a decay time of(67±37)μs,which is almost not affected by laser phase noise.We found that the maximum short-term laser frequency fluctuation of a single excitation lasers is at~3.3 k Hz and the maximum long-term laser frequency drift of a single laser is~46 k Hz during one month.Our work develops a stable and repeatable method to provide multiple laser sources of ultra-low phase noise,narrow linewidth,and excellent frequency stability,which is essential for high precision atomic experiments,such as neutral atom quantum computing,quantum simulation,quantum metrology,and so on.
基金supported by the National Natural Science Foundation of China(No.61377075)the Tianjin Natural Science Foundation(No.17JCYBJC16600)
文摘An optical modulation format generation scheme based on spectral filtering and frequency-to-time mapping is experimentally demonstrated. Many modulation formats with continuously adjustable duty radio and bit rate can be formed by changing the dispersion of dispersion element and the bandwidth of shaped spectrum in this scheme. In the experiment, non-return-to-zero(NRZ) signal with bit rate of 29.41 Gbit/s and 1/2 duty ratio return-to-zero(RZ) signal with bit rate of 13.51 Gbit/s are obtained. The maximum bit rate of modulation format signal is also analyzed.
基金supported by the National Natural Science Foundation of China(Grant No.10904079)
文摘According to electro-optical sampling theory, we propose a new method to detect the spatiotemporal field of a single- shot terahertz pulse by spectral holography for the first time. The single-shot terahertz pulse is coupled into a broadened chirped femtosecond pulse according to electro-optical sampling theory in the detecting system. Then the reference wave and the signal wave are split by Dammann grating and spread into the interference band-pass filter. The filtered sub-waves are at different central-frequencies because of the different incident angles. These sub-waves at different central-frequencies interfere to form sub-holograms, which are recorded in a single frame of a charge coupled device （CCD）. The sub-holograms are numerically processed, and the spatiotemporal field distribution of the original terahertz pulse is reconstructed. The computer simulations verify the feasibility of the proposed method.
基金Supported by the National High Technology Research and Development Program of China under Grant No 2015AA016904the National Key Research and Development Plan of China under Grant No 2016YFB0402502the National Natural Science Foundation of China under Grant No 61275065
文摘We demonstrate a highly compact third-order elliptical micro-ring add-drop filter based on a silicon-on-insulator wafer. The elliptical micro-ring resonator has a major radius of 6μm （minor radius of 4.112μm） and a large free spectral range of 18 nm. Experimental results show a box-like channel dropping response, which has a 3 dB bandwidth of -2.7nm, high out-of-band signal rejection of around 40dB and a very low drop loss （〈0.5dB）. Simulation agrees well with the experiments. The footprint of the whole chip is only 0.0003mm2.
基金Project supported by the National Natural Science Foundation of China （Grant No 10375022） and Scientific Research Fund of Hunan Provincial Education Department of China （Grant No 05C414）.
文摘Dark soliton solutions of the one-dimensional complex Ginzburg-Landau equation （CGLE） are analysed for the case of normal group-velocity dispersion. The CGLE can be transformed to the nonlinear Schrodinger equation （NLSE） with perturbation terms under some practical conditions. The main properties of dark solitons are analysed by applying the direct perturbation theory of the NLSE. The results obtained may be helpful for the research on the optical soliton transmission system.
文摘An experiment was carried out to examine the effects of light quality on the growth and development of antirrhinum under three different temperatures 19℃, 24℃ and 27℃ in glasshouses. Five different colour filters (i.e. 'Red absorbing', 'Blue absorbing', 'Blue and Red absorbing' and two 'partially Blue absorbing' materials) were tested, with one clear polythene as a control. Plant height, internode length and leaf area were significantly affected by the spectral filters as well as the temperature.Analysis of color filter's effect on presumed photoreceptors to exist indicated that antirrhinum plant height was regulated by the action of a blue acting photoreceptor (BAP) and not the phytochrome. There was no evidence for an effect ofphytochrome or BAP on time to flowering, however, increasing temperature levels effectively decreased the time to flowering. To predict the effects of different spectral qualities and temperature, simple models were created from data on plant height, internode length and time to flowering. These models were then applied to simulate the potential benefits of spectral filters and temperature in manipulation of growth control and flowering in antirrhinum.
基金the Natural Science Foundation of Beijing(No.7133252) for financial support of this work
文摘Xiao-Xu-Ming decoction（XXMD） was a traditional Chinese prescription and first recorded in ＂Bei Ji Qian Jin Yao Fang＂.It has been widely used to treat theoplegia and the sequel of theoplegia in China.In the present work,high-performance liquid chromatography coupled with high resolution mass spectrometry（HPLC-HRMS） combined with the mass spectral tree similarity filter technique（MTSF）was used to rapidly discover and identify the compounds of the active fraction of XXMD.A total of 3362 compounds were automatically detected by HPLC-HRMS,and final 68 compounds were identified in the active fraction of XXMD.including 14 templated compounds（reference compounds）,50 related compounds fished by MTSF technique,and 4 unrelated compounds identified by manual method.This study successfully applied MTSF technology for the first time to discover and identify the components of Chinese prescription.The results demonstrated that MTSF technique should be useful to the discovery and identification of compounds in Chinese prescription.This study also proved that MTSF can be applied to the targeted phytochemical separation.
基金Supported by the Cooperation Between BIT and Ericsson
文摘Associated with ITU-T G.719,a post-processing method in frequency domain for enhancing the perceptual quality of the decoded transient audio is proposed only to the audio decoder with no side information from the encoder.The proposed post-filter is used to filter the frequency coefficients of the decoded transient frame and consists of a short-term post-filter and a spectral tilt compensation filter which are derived from linear predictive coding（LPC） predictor based on the discrete cosine transform（DCT） coefficients of the decoded transient frame.As a result,the post-filter in frequency domain shapes the temporal noise in time domain and controls the pre-echo noise effectively while enhancing the transient perception.Listening test results show that the preferring ratio of the post-processed transient signal is higher than that of the original decoded signal at a low bit rate of 32 kbit/s in G.719 and the post-processing module brings a complexity of 12.399 WMOPS to the decoder.
文摘Transparent electro-optic(EO)oxide ceramics are known for their rapid EO effects.EO ceramics have several advantages over single-crystals,including variable size and shape,controllable chemical composition,superior mechanical properties,and low cost.Synthesis of high-performance transparent EO ceramics requires high purity of raw materials,high density,homogeneous composition,uniform grain size,and relatively wide bandgap.Powder synthesis and sintering are two of the critical steps involved in the fabrication of highly transparent EO ceramics.Using high-activity precursor powders has been effective in fabricating high-density ceramics that demonstrate excellent EO performance.The sintering process plays a crucial role in achieving this result,and currently,there are several sintering methods available for producing high-density ceramics,including hot-pressing,hot isostatic pressing,and spark plasma sintering.This review summarizes the recent progress in materials and processes used to develop transparent EO ceramics,including those based on lead zirconate titanate,lead magnesium niobate-lead titanate,and lead-free potassium sodium niobate.In addition,several novel applications of transparent EO ceramics,including light shutters,spectral filters,optical memory,as well as image storage and displays are reviewed.In the end,the review concludes with a discussion of future trends and perspectives.
基金This work was supported by the Science and Technology Commission of Shanghai Municipality(No.22DZ1100300).
文摘With the development of high-volume manufacturing for very-large-scale integrated circuits,the purity of the light source in the extreme ultraviolet lithography(EUVL)system needs to fulfil extreme requirements in order to avoid thermal effect,optical distortion and critical dimension errors caused by out-of-band radiations.This paper reviews the key technologies and developments of the spectral purity systems for both a free-standing system and a built-in system integrated with the collector.The main challenges and developing trends are also discussed,with a view towards practical applications for further improvement.Designing and manufacturing spectral purity systems for EUVL is not a single task;rather,it requires systematic considerations for all relevant modules.Moreover,the requirement of spectral purity filters drives the innovation in filtering technologies,optical micromachining and advanced metrology.
