We demonstrate absorption spectroscopy of water vapor for the determination of gas temperature. An adaptive dual-comb detection system is utilized to obtain precise spectroscopic data in a broadband range from 7143 to...We demonstrate absorption spectroscopy of water vapor for the determination of gas temperature. An adaptive dual-comb detection system is utilized to obtain precise spectroscopic data in a broadband range from 7143 to7240 cm^-1 with a spectral resolution of 0.049 cm^-1. The measured spectra are in accordance with the simulated results from the HITRAN(high-resolution transmission molecular absorption) database. Several measurements are investigated in the temperature range of 500–1000 K, revealing relative deviations of less than 5% compared to the thermocouple. This broadband and accurate adaptive dual-comb spectral detection method could be a powerful tool for non-invasive combustion diagnosis.展开更多
A composite transparent YAG/Yb:YAG/YAG ceramic was prepared by a non-aqueous tape-casting method. An optical transmittance of 82% was obtained at visible wavelength and around 1100 nm. A low-threshold, broadband tunab...A composite transparent YAG/Yb:YAG/YAG ceramic was prepared by a non-aqueous tape-casting method. An optical transmittance of 82% was obtained at visible wavelength and around 1100 nm. A low-threshold, broadband tunable continuous-wave(CW) laser at 1031 nm was further demonstrated from the ceramic sample, which was pumped by a974 nm fiber-pigtailed laser diode. The threshold pump power was 0.45 W and the maximum output power was 3.2 W,corresponding to a slope efficiency of 20.4%. By inserting an SF57 prism in the laser cavity, the output wavelength could be tuned continuously from 1021 to 1058 nm.展开更多
Period-doubling bifurcation,as an intermediate state between order and chaos,is ubiquitous in all disciplines of nonlinear science.However,previous experimental observations of period doubling in ultrafast fiber laser...Period-doubling bifurcation,as an intermediate state between order and chaos,is ubiquitous in all disciplines of nonlinear science.However,previous experimental observations of period doubling in ultrafast fiber lasers are mainly restricted to self-sustained steady state,controllable manipulation and dynamic switching between period doubling and other intriguing dynamical states are still largely unexplored.Here,we propose to expand the vision of dissipative soliton periodic doubling,which we illustrate experimentally by reporting original spontaneous,collisional,and controllable spectral period doubling in a polarization-maintaining ultrafast fiber laser.Specifically,the spontaneous period doubling can be observed in both single-and double-pulses.The mechanism of the switchable state and periodic doubling was revealed by numerical simulation.Moreover,state transformation of individual solitons can be resolved during the collision of triple solitons involving stationary,oscillating,and period doubling.Further,controllable deterministic switching between period doubling and other dynamical states,as well as exemplifying the application of period-doubling-based digital encoding,is achieved under programmable pump modulation.Our results open a new window for unveiling complex Hopf bifurcation in dissipative systems and bring useful insights into nonlinear science and applications.展开更多
基金the National Natural Science Foundation of China(Nos.11727812 and 11704253)the National Key R&D Program of China(No.2018YFB0407100)+1 种基金the Science and Technology Innovation Program of Basic Science Foundation of Shanghai(No.18JC1412000)the Shanghai Youth Science and Technology Talent Sailing Program(No.17YF1413100)。
文摘We demonstrate absorption spectroscopy of water vapor for the determination of gas temperature. An adaptive dual-comb detection system is utilized to obtain precise spectroscopic data in a broadband range from 7143 to7240 cm^-1 with a spectral resolution of 0.049 cm^-1. The measured spectra are in accordance with the simulated results from the HITRAN(high-resolution transmission molecular absorption) database. Several measurements are investigated in the temperature range of 500–1000 K, revealing relative deviations of less than 5% compared to the thermocouple. This broadband and accurate adaptive dual-comb spectral detection method could be a powerful tool for non-invasive combustion diagnosis.
基金supported by the Major Program of the National Natural Science Foundation of China (Grant No. 50990301)the Project for Young Scientists Fund of the National Natural Science Foundation of China (Grant Nos. 51002172 and 51302298)
文摘A composite transparent YAG/Yb:YAG/YAG ceramic was prepared by a non-aqueous tape-casting method. An optical transmittance of 82% was obtained at visible wavelength and around 1100 nm. A low-threshold, broadband tunable continuous-wave(CW) laser at 1031 nm was further demonstrated from the ceramic sample, which was pumped by a974 nm fiber-pigtailed laser diode. The threshold pump power was 0.45 W and the maximum output power was 3.2 W,corresponding to a slope efficiency of 20.4%. By inserting an SF57 prism in the laser cavity, the output wavelength could be tuned continuously from 1021 to 1058 nm.
基金supported by National Natural Science Foundation of China(12374402)Research Grants Council of the Hong Kong Special Administrative Region of China(HKU 17210522,HKU C7074-21G,HKU 17205321,HKU 17200219,MHP/073/20,MHP/057/21)Health@InnoHK program of the Innovation and Technology Commission of the Hong Kong SAR Government.
文摘Period-doubling bifurcation,as an intermediate state between order and chaos,is ubiquitous in all disciplines of nonlinear science.However,previous experimental observations of period doubling in ultrafast fiber lasers are mainly restricted to self-sustained steady state,controllable manipulation and dynamic switching between period doubling and other intriguing dynamical states are still largely unexplored.Here,we propose to expand the vision of dissipative soliton periodic doubling,which we illustrate experimentally by reporting original spontaneous,collisional,and controllable spectral period doubling in a polarization-maintaining ultrafast fiber laser.Specifically,the spontaneous period doubling can be observed in both single-and double-pulses.The mechanism of the switchable state and periodic doubling was revealed by numerical simulation.Moreover,state transformation of individual solitons can be resolved during the collision of triple solitons involving stationary,oscillating,and period doubling.Further,controllable deterministic switching between period doubling and other dynamical states,as well as exemplifying the application of period-doubling-based digital encoding,is achieved under programmable pump modulation.Our results open a new window for unveiling complex Hopf bifurcation in dissipative systems and bring useful insights into nonlinear science and applications.
