Wavelength-tunable organic semiconductor lasers based on mechanically stretchable polydimethylsiloxane (PDMS) gratings were developed. The intrinsic stretchability of PDMS was explored to modulate the period of the di...Wavelength-tunable organic semiconductor lasers based on mechanically stretchable polydimethylsiloxane (PDMS) gratings were developed. The intrinsic stretchability of PDMS was explored to modulate the period of the distributed feedback gratings for fine tuning the lasing wavelength. Notably, elastic lasers based on three typical light-emitting molecules show com-parable lasing threshold values analogous to rigid devices and a continuous wavelength tunability of about 10 nm by mechanic-al stretching. In addition, the stretchability provides a simple solution for dynamically tuning the lasing wavelength in a spec-tral range that is challenging to achieve for inorganic counterparts. Our work has provided a simple and efficient method of fab-ricating tunable organic lasers that depend on stretchable distributed feedback gratings, demonstrating a significant step in the advancement of flexible organic optoelectronic devices.展开更多
A 1550-nm linearly tunable continuous wave (CW) single-mode external cavity diode laser (ECDL) based on a singlecavity all-dielectric thin-film Fabry-Pérot filter (s-AFPF) is proposed and realized in this p...A 1550-nm linearly tunable continuous wave (CW) single-mode external cavity diode laser (ECDL) based on a singlecavity all-dielectric thin-film Fabry-Pérot filter (s-AFPF) is proposed and realized in this paper. Its internal optical components as well as their operation mechanisms are introduced first, and then its longitudinal mode output characteristic is theoretically analyzed. Afterwards, we set up the experimental platform for the output characteristic measurement of this tunable ECDL; under different experimental conditions, we execute accurate and real-time measurements for the output central wavelength, output optical power, output longitudinal mode distribution, and the line-width of the tunable ECDL in its tuning process. By summing up the optimal experimental condition from the measured data, we obtain the optimal tunable ECDL relevant parameters: the tunable ECDL has a linear mode-hop-free wavelength tuning region of 1547.203 nm-1552.426 nm, a stable output optical power in the range of 40 μW-50 μW, and a stable output longitudinal mode distribution of a single longitudinal mode with a line-width in the range of 100 MHz-150 MHz. This tunable ECDL can be used in environmental gas monitoring, atomic and molecular laser spectroscopy research, precise measurements, and so on.展开更多
We report the study on a short wavelength-tunable vertical-cavity surface-emitting laser utilizing a monolithically integrated bridge tuning microelectromechanical system. A deformable-bridge top mirror suspended abov...We report the study on a short wavelength-tunable vertical-cavity surface-emitting laser utilizing a monolithically integrated bridge tuning microelectromechanical system. A deformable-bridge top mirror suspended above an active region is utilized. Applied bridge-substrate bias produces an electrostatic force which reduces the spacing of air-gap and tunes the resonant wavelength toward a shorter wavelength (blue-shift), Good laser characteristics are obtained: such as continuous tuning ranges over 11 nm near 940 nm for 0-9 V tuning bias, the peak output power near 1 mW and the full-width-half-maximum limited to approximately 3.2-6.8 rim. A detailed simulation of the micromechanical and optical characteristics of these devices is performed, and the ratio of bridge displacement to wavelength shift has been found to be 3:1.展开更多
The design concept of semiconductor optical amplifier(SOA)and gain chip used in wavelength tunable lasers(TL)is discussed in this paper.The design concept is similar to that of a conventional SOA or a laser;however,th...The design concept of semiconductor optical amplifier(SOA)and gain chip used in wavelength tunable lasers(TL)is discussed in this paper.The design concept is similar to that of a conventional SOA or a laser;however,there are a few different points.An SOA in front of the tunable laser should be polarization dependent and has low optical confinement factor.To obtain wide gain bandwidth at the threshold current,the gain chip used in the tunable laser cavity should be something between SOA and fixed-wavelength laser design,while the fixed-wavelength laser has high optical confinement factor.Detailed discussion is given with basic equations and some simulation results on saturation power of the SOA and gain bandwidth of gain chip are shown.展开更多
Wavelength tunable and directly modulated distributed Bragg reflector (DBR) lasers with butt-joint technology are designed, fabricated and characterized. The DBR laser consists of a gain section and a DBR section. T...Wavelength tunable and directly modulated distributed Bragg reflector (DBR) lasers with butt-joint technology are designed, fabricated and characterized. The DBR laser consists of a gain section and a DBR section. To increase the electrical isolation between the gain section and the DBR section, parts of a p-doped material in the isolation region are etched off selectively. Over 2kΩ isolation resistance is realized ultimately without the need of ion implantation, which simplifies the fabrication process. The laser exhibits high speed modulation with a large tunable range. The 3dB direct modulation bandwidth of the device is over 8GHz in a 12nm tunable range. This widely tunable DBR laser with the simple structure is promising as a colorless light source for the next-generation time and wavelength division multiplexed passive optical network (TWDM-PON) systems.展开更多
Several high-performance and tunable erbium-doped fiber lasers are reviewed. They are constructed by using fiber Bragg gratings (FBGs) or short-wavelength-pass filters (SWPFs) as wavelength tunable components inside t...Several high-performance and tunable erbium-doped fiber lasers are reviewed. They are constructed by using fiber Bragg gratings (FBGs) or short-wavelength-pass filters (SWPFs) as wavelength tunable components inside the laser cavity. Broadband wavelength tuning range including C- and/or S-band was achieved, and tunable laser output with high slope efficiency, high side-mode suppression ratio was obtained. These fiber lasers can find vast applications in lightwave transmission, optical test instrument, fiber-optic gyros, spectroscopy, material processing, biophotonic imaging, and fiber sensor technologies.展开更多
Tunable diode laser absorption spectroscopy (TDLAS) has been widely employed in atmospheric trace gases detection. The ratio of the second-harmonic signal to the intensity of laser beam incident to the multi-pass ce...Tunable diode laser absorption spectroscopy (TDLAS) has been widely employed in atmospheric trace gases detection. The ratio of the second-harmonic signal to the intensity of laser beam incident to the multi-pass cell is proved to be proportional to the product of the path length and the gas concentration under any condition. A new calibration method based on this relation in TDLAS system for the measurement of trace gas concentration is proposed for the first time. The detection limit and the sensitivity of the system are below 110 and 31ppbv (parts-per-billion in volume), respectively.展开更多
As being an effective real-time method of monitoring vehicle emissions on-road, a remote sensing system based on the tunable diode laser (TDL) technology was presented, and the key technologies were discussed. A fie...As being an effective real-time method of monitoring vehicle emissions on-road, a remote sensing system based on the tunable diode laser (TDL) technology was presented, and the key technologies were discussed. A field test in Guangzhou(Guangdong, China) was performed and was found that the factors, such as slope, instantaneous speed and acceleration, had significant influence on the detectable rate of the system. Based on the results, the proposal choice of testing site was presented.展开更多
We demonstrate a passively Q-switched tunable erbium-doped fiber laser (EDFL) based on graphene as a saturable absorber (SA). A three-port optical circulator (OC) and a strain-induced tunable fiber Bragg grating...We demonstrate a passively Q-switched tunable erbium-doped fiber laser (EDFL) based on graphene as a saturable absorber (SA). A three-port optical circulator (OC) and a strain-induced tunable fiber Bragg grating (TFBG) are used as the two end mirrors in an all-fiber linear cavity. The Q-switched EDFL has a low pump threshold of 23.8 mW. The pulse repetition rate of the fiber laser can be widely changed from 9.3 kHz to 69.7 kHz by increasing the pump power from 23.8 mW to 219.9 mW. The minimum pulse duration is 1.7 p.s and the highest pulse energy is 25.4 nJ. The emission wavelength of the laser can be tuned from 1560.43 nm to 1566.27 nm by changing the central wavelength of the straininduced TFBG.展开更多
We introduce a new method of simultaneously implementing frequency stabilization and frequency shift for semiconductor lasers. We name this method the frequency tunable modulation transfer spectroscopy (FTMTS). To r...We introduce a new method of simultaneously implementing frequency stabilization and frequency shift for semiconductor lasers. We name this method the frequency tunable modulation transfer spectroscopy (FTMTS). To realize a stable output of 780 nm semiconductor laser, an FTMTS optical heterodyne frequency stabilization system is constructed. Before entering into the frequency stabilization system, the probe laser passes through an acousto-optical modulator (AOM) twice in advance to achieve tunable frequency while keeping the light path stable. According to the experimental results, the frequency changes from 120 MHz to 190 MHz after the double-pass AOM, and the intensity of laser entering into the system is greatly changed, but there is almost no change in the error signal of the FTMTS spectrum. Using this signal to lock the laser frequency, we can ensure that the frequency of the laser changes with the amount of AOM shift. Therefore, the magneto-optical trap (MOT)-molasses process can be implemented smoothly.展开更多
In this study, we demonstrate an all-fiber high-power linearly-polarized tunable Raman fiber laser system. An in- house high-power tunable fiber laser was employed as the pump source. A fiber loop mirror (FLM) servi...In this study, we demonstrate an all-fiber high-power linearly-polarized tunable Raman fiber laser system. An in- house high-power tunable fiber laser was employed as the pump source. A fiber loop mirror (FLM) serving as a high reflectivity mirror and a flat-cut endface serving as an output coupler were adopted to provide broadband feedback. A piece of 59-m commercial passive fiber was used as the Raman gain medium. The Raman laser had a 27.6 nm tuning range from 1112 nm to 1139.6 nm and a maximum output power of 125.3 W, which corresponds to a conversion efficiency of 79.4%. The polarization extinction ratio (PER) at all operational wavelengths was measured to be over 21 dB. To the best of our knowledge, this is the first report on a hundred-watt level linearly-polarized tunable Raman fiber laser.展开更多
Dynamically tunable laser sources are highly promising for realizing visionary concepts of integrated photonic circuits and other applications. In this paper, a Ga N-based laser with an integrated PN junction heater o...Dynamically tunable laser sources are highly promising for realizing visionary concepts of integrated photonic circuits and other applications. In this paper, a Ga N-based laser with an integrated PN junction heater on Si is fabricated.The photoluminescence properties of the Ga N beam cavity are controlled by temperature, and the Joule heater provides electrically driven regulation of temperature. These two features of the cavity make it possible to realize convenient tuning of the lasing properties. The multi-functional Ga N beam cavity achieves optically pumped lasing with a single mode near 362.4 nm with a high Q-factor of 1394. The temperature of this device increases by 0–5℃ under the Joule heating effect. Then, electrical control of the lasing mode is demonstrated. The lasing resonant peak shows a continuous redshift of about 0.5 nm and the device also exhibits dynamic switching of its lasing mode. The lasing modulation can be ascribed to temperature-induced reduction of the bandgap. Our work may be of benefit for external optical modulation in future chip-based optoelectronic devices.展开更多
A broadband external cavity tunable laser is realized by using a broad-emitting spectral InAs/GaAs quantum dot (QD) gain device. A tuning range of 69 nm with a central wavelength of 1056 nm, is achieved at a bias of...A broadband external cavity tunable laser is realized by using a broad-emitting spectral InAs/GaAs quantum dot (QD) gain device. A tuning range of 69 nm with a central wavelength of 1056 nm, is achieved at a bias of 1.25 kA/cm^2only by utilizing the light emission from the ground state of QDs. This large tunable range only covers the QD ground-state emission and is related to the inhomogeneous size distribution of QDs. No excited state contributes to the tuning bandwidth. The application of the QD gain device to the external cavity tunable laser shows its immense potential in broadening the tuning bandwidth. By the external cavity feedback, the threshold current densitycan be reduced remarkably compared with the free-running QD gain device.展开更多
We develop a picosecond widely tunable laser in a deep-ultraviolet region from 175 nm to 210 nm, generated by two stages of frequency doubling of a 80-MHz mode-locked picosecond Ti:sapphire laser. A β-BaB2O4 walk-of...We develop a picosecond widely tunable laser in a deep-ultraviolet region from 175 nm to 210 nm, generated by two stages of frequency doubling of a 80-MHz mode-locked picosecond Ti:sapphire laser. A β-BaB2O4 walk-off compensation configuration and a KBe2BO3F2 prism-coupled device are adopted for the generation of second harmonic and fourth harmonics, respectively. The highest power is 3.72 mW at 193 nm, and the fluctuation at 2.85 mW in 130 rain is less than ±2%.展开更多
Densities of Ar metastable states 1s5 and 1s3 are measured by using the tunable diode laser absorption spectroscopy(TDLAS) in Ar and Ar/O2 mixture dual-frequency capacitively coupled plasma(DF-CCP). We investigate...Densities of Ar metastable states 1s5 and 1s3 are measured by using the tunable diode laser absorption spectroscopy(TDLAS) in Ar and Ar/O2 mixture dual-frequency capacitively coupled plasma(DF-CCP). We investigate the effects of high-frequency(HF, 60 MHz) power, low-frequency(LF, 2 MHz) power, and working pressure on the density of Ar metastable states for three different gas components(0%, 5%, and 10% oxygen mixed in argon). The dependence of Ar metastable state density on the oxygen content is also studied at different working pressures. It is found that densities of Ar metastable states in discharges with different gas components exhibit different behaviors as HF power increases. With the increase of HF power, the metastable density increases rapidly at the initial stage, and then tends to be saturated at a higher HF power. With a small fraction(5% or 10%) of oxygen added in argon plasma, a similar change of the Ar metastable density with HF power can be observed, but the metastable density is saturated at a higher HF power than in the pure argon discharge. In the DF-CCP, the metastable density is found to be higher than in a single frequency discharge, and has weak dependence on LF power. As working pressure increases, the metastable state density first increases and then decreases,and the pressure value, at which the density maximum occurs, decreases with oxygen content increasing. Besides, adding a small fraction of oxygen into argon plasma will significantly dwindle the metastable state density as a result of quenching loss by oxygen molecules.展开更多
We implement an experimental study for the generation of wideband tunable femtosecond laser with a home-made power-scaled mode-locked fiber oscillator as the pump source.By coupling the sub-100 fs mode-locked pulses i...We implement an experimental study for the generation of wideband tunable femtosecond laser with a home-made power-scaled mode-locked fiber oscillator as the pump source.By coupling the sub-100 fs mode-locked pulses into a nonlinear photonic crystal fiber(NL-PCF),the exited spectra have significant nonlinear broadening and cover a spectra range of hundreds of nm.In experiment,by reasonably optimizing the structure parameters of NL-PCF and regulating the power of the incident pulses,femtosecond laser with tuning range of 900-1290 nm is realized.The research approach promotes the development of femtosecond lasers with center wavelengths out of the traditional laser gain media toward the direction of simplicity and ease of implementation.展开更多
We demonstrate a middle infrared ZnGeP_2 optical parametric oscillator pumped by the Q-switched Ho:GdVO_4 laser. When the incident Ho pump power is 4.12 W, the maximum average output power of the ZGP-OPO laser is 2.0...We demonstrate a middle infrared ZnGeP_2 optical parametric oscillator pumped by the Q-switched Ho:GdVO_4 laser. When the incident Ho pump power is 4.12 W, the maximum average output power of the ZGP-OPO laser is 2.05 W, corresponding to a slope efficiency of 74.6%. The ZGP-OPO laser produces 4.2 ns mid-infrared pulses at a pulse repetition rate of 5 kHz. In addition, we obtain 0.8 um of tunable range for the signal wave and 2.1 um of tunable range for the idler wave.展开更多
The wavelength-tunable and switchable narrow bandwidth mode-locking operation is demonstrated in an all fiber laser based on semiconductor-saturable absorber mirror (SESAM). Two narrow-band fiber Bragg gratings cent...The wavelength-tunable and switchable narrow bandwidth mode-locking operation is demonstrated in an all fiber laser based on semiconductor-saturable absorber mirror (SESAM). Two narrow-band fiber Bragg gratings centered at 1029.9nm and 1032nm respectively with a polarization controller inserted between them are used to realize the wavelength switchable between 1029.9nm and 1032nm. The laser delivers different pulse widths of 7.5ps for 1030nm and 20ps for 1032nm. The maximum output power for both could reach -6.5mW at single pulse operation. The output wavelength couM be tuned to about 0.gnm intervals ranging from 1030.2nm to 1031.1 nm and from 1032.15nm to 1033.7nm with the temperature change of the fiber Bragg grating, respectively.展开更多
A tunable single-passband microwave photonic filter is proposed and demonstrated, based on a laser diode (LD) array with multiple optical carriers and a Fabry-Perot (F-P) laser diode. Multiple optical carriers in conj...A tunable single-passband microwave photonic filter is proposed and demonstrated, based on a laser diode (LD) array with multiple optical carriers and a Fabry-Perot (F-P) laser diode. Multiple optical carriers in conjunction with the F-P LD will realize a filter with multiple passbands. By adjusting the wavelengths of the multiple optical carriers, multiple passbands are merged into a single passband with a broadened bandwidth. By varying the number of the optical carrier, the bandwidth can be adjusted. The central frequency can be tuned by adjusting the wavelength of the multiple optical carriers simultaneously. A single-passband filter implemented by two optical carriers is experimentally demonstrated.展开更多
A high-pulse-energy high-beam-quality tunable Ti:sapphire laser pumped by a frequency-doubled Nd:YAG laser is demonstrated. Using a fused-silica prism as the dispersion element, a tuning range of 740-855 nm is obtai...A high-pulse-energy high-beam-quality tunable Ti:sapphire laser pumped by a frequency-doubled Nd:YAG laser is demonstrated. Using a fused-silica prism as the dispersion element, a tuning range of 740-855 nm is obtained. At an incident pump energy of 774mJ, the maximum output energy of 104mJ at 790nm with a pulse width of 100μs is achieved at a repetition rate of 5 Hz. To the best of our knowledge, it is the highest pulse energy at 790 nm with pulse width of hundred micro-seconds for an all-solid-state laser. The linewidth of output is 0.5 nm, and the beam quality factor M2 is 1.16. The high-pulse-energy high-beam-quality tunable Ti:sapphire laser in the range of 740-855 nm can be used to establish a more accurate and consistent absolute scale of second-order optical-nonlinear coefficients for KBe2BO3F2 measured in a wider wavelength range and to assess Miller's rule quantitatively.展开更多
基金financial support from the National Natural Science Foundation of China (21835003, 91833304,21422402, 62274097, 21674050, 62004106)the National Key Basic Research Program of China (2014CB648300,2017YFB0404501)+11 种基金the Natural Science Foundation of Jiangsu Province (BE2019120, BK20160888)Program for Jiangsu Specially-Appointed Professor (RK030STP15001)the Six Talent Peaks Project of Jiangsu Province (TD-XCL-009)the333 Project of Jiangsu Province (BRA2017402)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China (20KJB140005)China Postdoctoral Science Foundation (2020M671553)the NUPT"1311 Project"and Scientific Foundation (NY217169, NY215062, NY215107,NY217087)the Leading Talent of Technological Innovation of National Ten-Thousands Talents Program of Chinathe Excellent Scientific and Technological Innovative Teams of Jiangsu Higher Education Institutions (TJ217038)the Postgraduate Research&Practice Innovation Program of Jiangsu Province (SJCX21-0297)the Synergetic Innovation Center for Organic Electronics and Information Displaysthe Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)
文摘Wavelength-tunable organic semiconductor lasers based on mechanically stretchable polydimethylsiloxane (PDMS) gratings were developed. The intrinsic stretchability of PDMS was explored to modulate the period of the distributed feedback gratings for fine tuning the lasing wavelength. Notably, elastic lasers based on three typical light-emitting molecules show com-parable lasing threshold values analogous to rigid devices and a continuous wavelength tunability of about 10 nm by mechanic-al stretching. In addition, the stretchability provides a simple solution for dynamically tuning the lasing wavelength in a spec-tral range that is challenging to achieve for inorganic counterparts. Our work has provided a simple and efficient method of fab-ricating tunable organic lasers that depend on stretchable distributed feedback gratings, demonstrating a significant step in the advancement of flexible organic optoelectronic devices.
基金the Key Laboratory of Functional Crystals and Laser Technology,Chinese Academy of Sciences(Grant No.JTJG201109)the Guangdong Province&Chinese Academy of Sciences Comprehensive Strategic Cooperation Project(Grant No.2010A090100014)the 2009 Technology Research and Development Fund of Shenzhen,China(Grant No.O702011001)
文摘A 1550-nm linearly tunable continuous wave (CW) single-mode external cavity diode laser (ECDL) based on a singlecavity all-dielectric thin-film Fabry-Pérot filter (s-AFPF) is proposed and realized in this paper. Its internal optical components as well as their operation mechanisms are introduced first, and then its longitudinal mode output characteristic is theoretically analyzed. Afterwards, we set up the experimental platform for the output characteristic measurement of this tunable ECDL; under different experimental conditions, we execute accurate and real-time measurements for the output central wavelength, output optical power, output longitudinal mode distribution, and the line-width of the tunable ECDL in its tuning process. By summing up the optimal experimental condition from the measured data, we obtain the optimal tunable ECDL relevant parameters: the tunable ECDL has a linear mode-hop-free wavelength tuning region of 1547.203 nm-1552.426 nm, a stable output optical power in the range of 40 μW-50 μW, and a stable output longitudinal mode distribution of a single longitudinal mode with a line-width in the range of 100 MHz-150 MHz. This tunable ECDL can be used in environmental gas monitoring, atomic and molecular laser spectroscopy research, precise measurements, and so on.
基金Project supported by the National Natural Science Foundation of China (Grant No 60506012), the Fok Ying-Tong Foundation (Grant No 101062), the Natural Science Foundation of Beijing China (Grant No KZ200510005003), the Science Star of Beijing China (Grant No 2005A11), and the Funding Project for Academic Human Resources Development in Institutions of Higher Learning Under the Jurisdiction of Beijing Municipality China (Grant No 20051D0501502).Acknowledgement The authors gratefully acknowledge the staff of M0CVD, Zhou Deshu, and Han Jinru for technical assistance. The authors also thank Professor Academician Chen Lianghui, Professor Tan Manqing and Mr Wang Xuming at the Institute of Semiconductors, CAS for technological support in device fabrication.
文摘We report the study on a short wavelength-tunable vertical-cavity surface-emitting laser utilizing a monolithically integrated bridge tuning microelectromechanical system. A deformable-bridge top mirror suspended above an active region is utilized. Applied bridge-substrate bias produces an electrostatic force which reduces the spacing of air-gap and tunes the resonant wavelength toward a shorter wavelength (blue-shift), Good laser characteristics are obtained: such as continuous tuning ranges over 11 nm near 940 nm for 0-9 V tuning bias, the peak output power near 1 mW and the full-width-half-maximum limited to approximately 3.2-6.8 rim. A detailed simulation of the micromechanical and optical characteristics of these devices is performed, and the ratio of bridge displacement to wavelength shift has been found to be 3:1.
文摘The design concept of semiconductor optical amplifier(SOA)and gain chip used in wavelength tunable lasers(TL)is discussed in this paper.The design concept is similar to that of a conventional SOA or a laser;however,there are a few different points.An SOA in front of the tunable laser should be polarization dependent and has low optical confinement factor.To obtain wide gain bandwidth at the threshold current,the gain chip used in the tunable laser cavity should be something between SOA and fixed-wavelength laser design,while the fixed-wavelength laser has high optical confinement factor.Detailed discussion is given with basic equations and some simulation results on saturation power of the SOA and gain bandwidth of gain chip are shown.
基金Supported by the National Key Project under Grant No 2016YFB0402301the National High Technology Research and Development Program of China under Grant No 2013AA014502the National Natural Science Foundation of China under Grant Nos 61635010,61320106013,61474112,61321063 and 61274071
文摘Wavelength tunable and directly modulated distributed Bragg reflector (DBR) lasers with butt-joint technology are designed, fabricated and characterized. The DBR laser consists of a gain section and a DBR section. To increase the electrical isolation between the gain section and the DBR section, parts of a p-doped material in the isolation region are etched off selectively. Over 2kΩ isolation resistance is realized ultimately without the need of ion implantation, which simplifies the fabrication process. The laser exhibits high speed modulation with a large tunable range. The 3dB direct modulation bandwidth of the device is over 8GHz in a 12nm tunable range. This widely tunable DBR laser with the simple structure is promising as a colorless light source for the next-generation time and wavelength division multiplexed passive optical network (TWDM-PON) systems.
文摘Several high-performance and tunable erbium-doped fiber lasers are reviewed. They are constructed by using fiber Bragg gratings (FBGs) or short-wavelength-pass filters (SWPFs) as wavelength tunable components inside the laser cavity. Broadband wavelength tuning range including C- and/or S-band was achieved, and tunable laser output with high slope efficiency, high side-mode suppression ratio was obtained. These fiber lasers can find vast applications in lightwave transmission, optical test instrument, fiber-optic gyros, spectroscopy, material processing, biophotonic imaging, and fiber sensor technologies.
基金Project supported by the National Natural Science Foundation of China (Grant No 10274080) and the National High Technology Research and Development Program of China (Grant No 2003AA641010).
文摘Tunable diode laser absorption spectroscopy (TDLAS) has been widely employed in atmospheric trace gases detection. The ratio of the second-harmonic signal to the intensity of laser beam incident to the multi-pass cell is proved to be proportional to the product of the path length and the gas concentration under any condition. A new calibration method based on this relation in TDLAS system for the measurement of trace gas concentration is proposed for the first time. The detection limit and the sensitivity of the system are below 110 and 31ppbv (parts-per-billion in volume), respectively.
文摘As being an effective real-time method of monitoring vehicle emissions on-road, a remote sensing system based on the tunable diode laser (TDL) technology was presented, and the key technologies were discussed. A field test in Guangzhou(Guangdong, China) was performed and was found that the factors, such as slope, instantaneous speed and acceleration, had significant influence on the detectable rate of the system. Based on the results, the proposal choice of testing site was presented.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.61077017 and 61378028)the Program for New Century Excellent Talents in University,China (Grant Nos.NCET-11-0069 and NCET-10-0291)the 111 Project (Grant No.B13042)
文摘We demonstrate a passively Q-switched tunable erbium-doped fiber laser (EDFL) based on graphene as a saturable absorber (SA). A three-port optical circulator (OC) and a strain-induced tunable fiber Bragg grating (TFBG) are used as the two end mirrors in an all-fiber linear cavity. The Q-switched EDFL has a low pump threshold of 23.8 mW. The pulse repetition rate of the fiber laser can be widely changed from 9.3 kHz to 69.7 kHz by increasing the pump power from 23.8 mW to 219.9 mW. The minimum pulse duration is 1.7 p.s and the highest pulse energy is 25.4 nJ. The emission wavelength of the laser can be tuned from 1560.43 nm to 1566.27 nm by changing the central wavelength of the straininduced TFBG.
基金Project supported by the National Key Scientific Instrument and Equipment Development Project,China(Grant No.2014YQ35046103)
文摘We introduce a new method of simultaneously implementing frequency stabilization and frequency shift for semiconductor lasers. We name this method the frequency tunable modulation transfer spectroscopy (FTMTS). To realize a stable output of 780 nm semiconductor laser, an FTMTS optical heterodyne frequency stabilization system is constructed. Before entering into the frequency stabilization system, the probe laser passes through an acousto-optical modulator (AOM) twice in advance to achieve tunable frequency while keeping the light path stable. According to the experimental results, the frequency changes from 120 MHz to 190 MHz after the double-pass AOM, and the intensity of laser entering into the system is greatly changed, but there is almost no change in the error signal of the FTMTS spectrum. Using this signal to lock the laser frequency, we can ensure that the frequency of the laser changes with the amount of AOM shift. Therefore, the magneto-optical trap (MOT)-molasses process can be implemented smoothly.
基金Project supported by the Fok Ying-Tong Education Foundation,China(Grant No.151062)
文摘In this study, we demonstrate an all-fiber high-power linearly-polarized tunable Raman fiber laser system. An in- house high-power tunable fiber laser was employed as the pump source. A fiber loop mirror (FLM) serving as a high reflectivity mirror and a flat-cut endface serving as an output coupler were adopted to provide broadband feedback. A piece of 59-m commercial passive fiber was used as the Raman gain medium. The Raman laser had a 27.6 nm tuning range from 1112 nm to 1139.6 nm and a maximum output power of 125.3 W, which corresponds to a conversion efficiency of 79.4%. The polarization extinction ratio (PER) at all operational wavelengths was measured to be over 21 dB. To the best of our knowledge, this is the first report on a hundred-watt level linearly-polarized tunable Raman fiber laser.
基金the Natural Science Foundation of Jiangsu Province, China (Grant No. BK20210593)the Foundation of Jiangsu Provincial Double Innovation Doctor Program (Grant No. 30644)+2 种基金the National Natural Science Foundation of China (Grant No. 62204127)State Key Laboratory of Luminescence and Applications (Grant No. SKLA 202104)open research fund of Key Lab of Broadband Wireless Communication and Sensor Network Technology (Nanjing University of Posts and Telecommunications, Ministry of Education)。
文摘Dynamically tunable laser sources are highly promising for realizing visionary concepts of integrated photonic circuits and other applications. In this paper, a Ga N-based laser with an integrated PN junction heater on Si is fabricated.The photoluminescence properties of the Ga N beam cavity are controlled by temperature, and the Joule heater provides electrically driven regulation of temperature. These two features of the cavity make it possible to realize convenient tuning of the lasing properties. The multi-functional Ga N beam cavity achieves optically pumped lasing with a single mode near 362.4 nm with a high Q-factor of 1394. The temperature of this device increases by 0–5℃ under the Joule heating effect. Then, electrical control of the lasing mode is demonstrated. The lasing resonant peak shows a continuous redshift of about 0.5 nm and the device also exhibits dynamic switching of its lasing mode. The lasing modulation can be ascribed to temperature-induced reduction of the bandgap. Our work may be of benefit for external optical modulation in future chip-based optoelectronic devices.
基金Project supported by the National Basic Research Program of China (Grant No. 2006CB604904)the National Natural Science Foundation of China (Grant Nos. 60976057, 60876086 and 60776037)
文摘A broadband external cavity tunable laser is realized by using a broad-emitting spectral InAs/GaAs quantum dot (QD) gain device. A tuning range of 69 nm with a central wavelength of 1056 nm, is achieved at a bias of 1.25 kA/cm^2only by utilizing the light emission from the ground state of QDs. This large tunable range only covers the QD ground-state emission and is related to the inhomogeneous size distribution of QDs. No excited state contributes to the tuning bandwidth. The application of the QD gain device to the external cavity tunable laser shows its immense potential in broadening the tuning bandwidth. By the external cavity feedback, the threshold current densitycan be reduced remarkably compared with the free-running QD gain device.
基金supported by the State Key Program for Basic Research of China (Grant No. 2010CB630706)National High Technology Research and Development Program of Chinathe National Natural Science Foundation of China (Grant No. 61138004)
文摘We develop a picosecond widely tunable laser in a deep-ultraviolet region from 175 nm to 210 nm, generated by two stages of frequency doubling of a 80-MHz mode-locked picosecond Ti:sapphire laser. A β-BaB2O4 walk-off compensation configuration and a KBe2BO3F2 prism-coupled device are adopted for the generation of second harmonic and fourth harmonics, respectively. The highest power is 3.72 mW at 193 nm, and the fluctuation at 2.85 mW in 130 rain is less than ±2%.
基金supported by the National Natural Science Foundation of China(Grant Nos.11335004,11722541,11675039,and 11747153)the Important National Science and Technology Specific Project,China(Grant No.2011ZX02403-001)
文摘Densities of Ar metastable states 1s5 and 1s3 are measured by using the tunable diode laser absorption spectroscopy(TDLAS) in Ar and Ar/O2 mixture dual-frequency capacitively coupled plasma(DF-CCP). We investigate the effects of high-frequency(HF, 60 MHz) power, low-frequency(LF, 2 MHz) power, and working pressure on the density of Ar metastable states for three different gas components(0%, 5%, and 10% oxygen mixed in argon). The dependence of Ar metastable state density on the oxygen content is also studied at different working pressures. It is found that densities of Ar metastable states in discharges with different gas components exhibit different behaviors as HF power increases. With the increase of HF power, the metastable density increases rapidly at the initial stage, and then tends to be saturated at a higher HF power. With a small fraction(5% or 10%) of oxygen added in argon plasma, a similar change of the Ar metastable density with HF power can be observed, but the metastable density is saturated at a higher HF power than in the pure argon discharge. In the DF-CCP, the metastable density is found to be higher than in a single frequency discharge, and has weak dependence on LF power. As working pressure increases, the metastable state density first increases and then decreases,and the pressure value, at which the density maximum occurs, decreases with oxygen content increasing. Besides, adding a small fraction of oxygen into argon plasma will significantly dwindle the metastable state density as a result of quenching loss by oxygen molecules.
基金Project supported by the National Natural Science Foundation of China(Grant No.61805274)the Major Program of the National Natural Science Foundation of China(Grant No.12034020)Research Foundation of Inner Mongolia University of China(Grant No.21200-5215108)。
文摘We implement an experimental study for the generation of wideband tunable femtosecond laser with a home-made power-scaled mode-locked fiber oscillator as the pump source.By coupling the sub-100 fs mode-locked pulses into a nonlinear photonic crystal fiber(NL-PCF),the exited spectra have significant nonlinear broadening and cover a spectra range of hundreds of nm.In experiment,by reasonably optimizing the structure parameters of NL-PCF and regulating the power of the incident pulses,femtosecond laser with tuning range of 900-1290 nm is realized.The research approach promotes the development of femtosecond lasers with center wavelengths out of the traditional laser gain media toward the direction of simplicity and ease of implementation.
基金Supported by the National Natural Science Foundation of China under Grant No 51572053
文摘We demonstrate a middle infrared ZnGeP_2 optical parametric oscillator pumped by the Q-switched Ho:GdVO_4 laser. When the incident Ho pump power is 4.12 W, the maximum average output power of the ZGP-OPO laser is 2.05 W, corresponding to a slope efficiency of 74.6%. The ZGP-OPO laser produces 4.2 ns mid-infrared pulses at a pulse repetition rate of 5 kHz. In addition, we obtain 0.8 um of tunable range for the signal wave and 2.1 um of tunable range for the idler wave.
基金Supported by the National High Technology Research and Development Program of China under Grant No 2014AA041901NSAF Foundation of the National Natural Science Foundation of China under Grant No U1330134+1 种基金the Opening Project of Shanghai Key Laboratory of All Solid-State Laser and Applied Techniques under Grant No 2012ADL02the National Natural Science Foundation of China under Grant Nos 61308024 and 11174305
文摘The wavelength-tunable and switchable narrow bandwidth mode-locking operation is demonstrated in an all fiber laser based on semiconductor-saturable absorber mirror (SESAM). Two narrow-band fiber Bragg gratings centered at 1029.9nm and 1032nm respectively with a polarization controller inserted between them are used to realize the wavelength switchable between 1029.9nm and 1032nm. The laser delivers different pulse widths of 7.5ps for 1030nm and 20ps for 1032nm. The maximum output power for both could reach -6.5mW at single pulse operation. The output wavelength couM be tuned to about 0.gnm intervals ranging from 1030.2nm to 1031.1 nm and from 1032.15nm to 1033.7nm with the temperature change of the fiber Bragg grating, respectively.
基金Supported by the National Natural Science Foundation of China under Grant Nos 61302026,61275067 and 61575034the Jiangsu Natural Science Foundation under Grant No BK2012432
文摘A tunable single-passband microwave photonic filter is proposed and demonstrated, based on a laser diode (LD) array with multiple optical carriers and a Fabry-Perot (F-P) laser diode. Multiple optical carriers in conjunction with the F-P LD will realize a filter with multiple passbands. By adjusting the wavelengths of the multiple optical carriers, multiple passbands are merged into a single passband with a broadened bandwidth. By varying the number of the optical carrier, the bandwidth can be adjusted. The central frequency can be tuned by adjusting the wavelength of the multiple optical carriers simultaneously. A single-passband filter implemented by two optical carriers is experimentally demonstrated.
基金Supported by the National Natural Science Foundation of China under Grant Nos 61275157 and 61475040the National Key Scientific Instrument and Equipment Development,Project under Grant No 2012YQ120048+1 种基金the National Development Project for Major Scientific Research Facility under Grant No ZDYZ2012-2the National Key Research and Development Program of China under Grant No 2016YFB0402003
文摘A high-pulse-energy high-beam-quality tunable Ti:sapphire laser pumped by a frequency-doubled Nd:YAG laser is demonstrated. Using a fused-silica prism as the dispersion element, a tuning range of 740-855 nm is obtained. At an incident pump energy of 774mJ, the maximum output energy of 104mJ at 790nm with a pulse width of 100μs is achieved at a repetition rate of 5 Hz. To the best of our knowledge, it is the highest pulse energy at 790 nm with pulse width of hundred micro-seconds for an all-solid-state laser. The linewidth of output is 0.5 nm, and the beam quality factor M2 is 1.16. The high-pulse-energy high-beam-quality tunable Ti:sapphire laser in the range of 740-855 nm can be used to establish a more accurate and consistent absolute scale of second-order optical-nonlinear coefficients for KBe2BO3F2 measured in a wider wavelength range and to assess Miller's rule quantitatively.