This paper reports a continuous-wave (CW) mid-infrared intracavity singly resonant optical parametric oscillator based on periodically poled lithium niobate (PPLN) pumped by a diode-end-pumped CW Nd:YVO4 laser. C...This paper reports a continuous-wave (CW) mid-infrared intracavity singly resonant optical parametric oscillator based on periodically poled lithium niobate (PPLN) pumped by a diode-end-pumped CW Nd:YVO4 laser. Considering the thermal lens effects, it adopted an optical ballast lens and the near-concentric cavity for better operation. At the PPLN's grating period of 28.5 μm and the temperature of 140℃, the maximum idler output power of 155 mW at 3.86 μm has been achieved when the 808 nm pump power is 8.5 W, leading to an optical-to-optical conversion efficiency of 1.82%.展开更多
In this paper we report on a continuous-wave (CW) intracavity singly resonant optical parametric oscillator (ICSRO) based on periodically poled LiNbO3 (PPLN) pumped by a diode-end-pumped CW Nd:YVO4 laser. Consi...In this paper we report on a continuous-wave (CW) intracavity singly resonant optical parametric oscillator (ICSRO) based on periodically poled LiNbO3 (PPLN) pumped by a diode-end-pumped CW Nd:YVO4 laser. Considering the thermal lens effects and diffraction loss, an optical ballast lens and a near-concentric cavity are adopted for better operation. Through varying the grating period and the temperature, the tunable signal output from 1406 nm to 1513 nm is obtained. At a PPLN grating period of 29 pm and a temperature of 413 K, a maximum signal output power of 820 mW at 1500 nm is achieved when the 808 nm pump power is 10.9 W, leading to an optical-to-optical conversion efficiency of 7.51%.展开更多
We demonstrated a continuous wave(cw) single-frequency intracavity frequency-doubled Nd:YVO_4/LBO laser with 532 nm output of 7.5 W and 1.06 μm output of 3.1 W, and low intensity noise in audio frequency region.To su...We demonstrated a continuous wave(cw) single-frequency intracavity frequency-doubled Nd:YVO_4/LBO laser with 532 nm output of 7.5 W and 1.06 μm output of 3.1 W, and low intensity noise in audio frequency region.To suppress the intensity noise of the high power 532 nm laser, a laser frequency locking system and a feedback loop based on a Mach-Zehnder interferometer were designed and used.The influences of the frequency stabilization and the crucial parameters of the MZI, such as the power splitting ratio of the beam splitters and the locking state of the MZI, on the intensity noise of the 532 nm laser were investigated in detail.After the experimental optimizations, the laser intensity noise in the frequency region from 0.4 kHz to 10 kHz was significantly suppressed.展开更多
We demonstrate a tunable continuous-wave single frequency intracavity frequency-doubled Ti:sapphire laser.The highest output power of 280 mW at 461.62 nm is obtained by employing a type-I phase-matched BIBO crystal an...We demonstrate a tunable continuous-wave single frequency intracavity frequency-doubled Ti:sapphire laser.The highest output power of 280 mW at 461.62 nm is obtained by employing a type-I phase-matched BIBO crystal and the peak-to-peak fluctuation of the power is less than±1%within three hours.The frequency stability is better than±2.22 MHz over 10 min when the laser is locked to a confocal Fabry–Perot cavity.A three-plate birefringent filter allows for the tunable range from 457 nm to 467 nm,which covers the absorption line of the strontium atoms(460.86 nm).展开更多
We present a model of passively Q-switched Raman lasers by utilizing the rate equations. The intracavity fun-damental photon density, Raman photon density and the initial population-inversion density of the gain mediu...We present a model of passively Q-switched Raman lasers by utilizing the rate equations. The intracavity fun-damental photon density, Raman photon density and the initial population-inversion density of the gain medium are assumed to be of Gaussian spatial distributions. These rate equations are normalized by introducing some synthetic parameters and solved numerically, and a group of general curves are generated. Prom these curves we can understand the dependence of the Raman laser pulse characteristics on the parameters about the pumping, the gain medium, the Raman medium and the resonator. An illustrative calculation for a passively Q-switched Nd^3+:GdVO4 self-Raman laser is presented to demonstrate the usage of the curves and related formulas.展开更多
We demonstrated experimentally a synchronously pumped intracavity frequency-doubled femtosecond optical para- metric oscillator (OPO) using a periodically-poled lithium niobate (PPLN) as the nonlinear material in ...We demonstrated experimentally a synchronously pumped intracavity frequency-doubled femtosecond optical para- metric oscillator (OPO) using a periodically-poled lithium niobate (PPLN) as the nonlinear material in combination with a lithium triborate (LBO) as the doubling crystal. A Kerr-lens-mode-locked (KLM) Ti:sapphire oscillator at the wavelength of 790 nm was used as the pump source, which was capable of generating pulses with a duration as short as 117 fs. A tunable femtosecond laser covering the 624-672 nm range was realized by conveniently adjusting the OPO cavity length. A maximum average output power of 260 mW in the visible range was obtained at the pump power of 2.2 W, with a typical pulse duration of 205 fs assuming a sech2 pulse profile.展开更多
A four-wavelength Bragg reflection waveguide edge emitting diode based on intracavity spontaneous parametric down-conversion and four-wave mixing (FWM) processes is made. The structure and its tuning characteris- ti...A four-wavelength Bragg reflection waveguide edge emitting diode based on intracavity spontaneous parametric down-conversion and four-wave mixing (FWM) processes is made. The structure and its tuning characteris- tic are designed by the aid of FDTD mode solution. The laser structure is grown by molecular beam epitaxy and processed to laser diode through the semiconductor manufacturing technology. Fourier transform infrared spectroscopy is applied to record wavelength information. Pump around 1.071 μm, signal around 1.77μm, idler around 2.71 μm and FWM signal around 1.35μm are observed at an injection current of 560mA. The influ- ences of temperature, carrier density and pump wavelength on tuning characteristic are shown numerically and experimentally.展开更多
A high efficiency,low threshold,high repetition rate H-βFraunhofer line light at 486.1 nm was demonstrated.A high-efficiency KTP optical parametric oscillator was achieved by double-pass pumping with a high-maturity ...A high efficiency,low threshold,high repetition rate H-βFraunhofer line light at 486.1 nm was demonstrated.A high-efficiency KTP optical parametric oscillator was achieved by double-pass pumping with a high-maturity 5 kHz 532 nm laser.Thanks to the efficient intracavity frequency doubling of the circulating signal wave by a BIBO crystal,the threshold pump power of the 486.1 nm output was 0.9 W,and the maximum output power of 1.6 W was achieved under the pump power of7.5 W.The optical–optical conversion efficiency was 21.3%,with the pulse duration of 45.2 ns,linewidth of~0.12 nm,and beam quality factor M~2 of 2.83.展开更多
We have demonstrated a high-average-power,high-repetition-rate optical terahertz(THz)source based on difference frequency generation(DFG)in the GaSe crystal by using a near-degenerate 2μm intracavity KTP optical para...We have demonstrated a high-average-power,high-repetition-rate optical terahertz(THz)source based on difference frequency generation(DFG)in the GaSe crystal by using a near-degenerate 2μm intracavity KTP optical parametric oscillator as the pump source.The power of the 2μm dual-wavelength laser was up to 12.33 W with continuous tuning ranges of 1988.0–2196.2 nm/2278.4–2065.6 nm for two waves.Different GaSe cystal lengths have been experimentally investigated for the DFG THz source in order to optimize the THz output power,which was in good agreement with the theoretical analysis.Based on an 8 mm long GaSe crystal,the THz wave was continuously tuned from 0.21 to 3 THz.The maximum THz average power of 1.66μW was obtained at repetition rate of 10 kHz under 1.48 THz.The single pulse energy amounted to 166 pJ and the conversion efficiency from 2 μm laser to THz output was 1.68×10^(-6).The signal-to-noise ratio of the detected THz voltage was 23 dB.The acceptance angle of DFG in the GaSe crystal was measured to be 0.16°.展开更多
A wavelength-tunable and dual-wavelength mode-locking operation is achieved in an Er-doped fiber laser using a hybrid no-core fiber graded index multimode fiber as the saturable absorber. In the tuning operation, cont...A wavelength-tunable and dual-wavelength mode-locking operation is achieved in an Er-doped fiber laser using a hybrid no-core fiber graded index multimode fiber as the saturable absorber. In the tuning operation, continuously wavelength-tunable pulses with a tuning range of 46.7 nm, stable 3-dB bandwidth of around 5 nm, and pulse duration of ~850 fs are obtained by increasing the intracavity loss of a variable optical attenuator. In the dual-wavelength operation, the two solitons at different wavelengths demonstrate the characteristics of mutual coherence. By increasing the intracavity loss, the spectral spacing can be tuned from 11 to 33.01 nm while maintaining the coherence of the solitons. Such coherent solitons have high potential for applications in dual-comb frequency and multicolor pulses in nonlinear microscopy.展开更多
A quasi-continuous-wave intracavity frequency-doubled Nd:YAG laser which operates at 660 nm is studied. By using a flat-flat laser cavity, 2 Kr-lamps, KTP crystal and an acousto-optically Q-switch, 2-W output power at...A quasi-continuous-wave intracavity frequency-doubled Nd:YAG laser which operates at 660 nm is studied. By using a flat-flat laser cavity, 2 Kr-lamps, KTP crystal and an acousto-optically Q-switch, 2-W output power at 660 nm is obtained. The relationship between laser cavity length and output power is analyzed.展开更多
The spatial distributions of the pumping,the population inversion density,and the intracavity photon densities of the fundamental and the second harmonic are taken into account in the rate equations of the intracavity...The spatial distributions of the pumping,the population inversion density,and the intracavity photon densities of the fundamental and the second harmonic are taken into account in the rate equations of the intracavity-frequency-doubled cw lasers.By normalizing the related parameters,it is shown that the general solution of these space-dependent rate equations is dependent upon three dimensionless parameters:the pump to laser-mode size ratio,the normalized pump level,and a parameter written as ηSHG,which is related to the ability of the nonlinear crystal to convert the fundamental to the second harmonic.By numerically solving these rate equations,a group of general curves are obtained to express the relations between the solution and the three dimensionless parameters.In addition,the optimal pump to laser-mode size ratio and the optimal ηSHG are determined.A comparison with the result obtained under the plane-wave approximation is also given.展开更多
Cavity quantum electrodynamics (QED) is mainly re- searching the interaction process with a coherent atomic medium placed inside an optical resonant cavity, and has been of great interest in recent years. A well-kno...Cavity quantum electrodynamics (QED) is mainly re- searching the interaction process with a coherent atomic medium placed inside an optical resonant cavity, and has been of great interest in recent years. A well-known cavity- QED effect is the vacuum Rabi splitting or normal-mode splitting phenomenon that is under the strong coupling condition,展开更多
In this letter, a thin slab of glass is used as Fabry-Perot etalon inside a cavity of a continuous wave (CW) Nd:YAG laser to change the behavior of its output longitudinal modes. The slab etalon is used as tuning e...In this letter, a thin slab of glass is used as Fabry-Perot etalon inside a cavity of a continuous wave (CW) Nd:YAG laser to change the behavior of its output longitudinal modes. The slab etalon is used as tuning element when it turns around the laser cavity axis. Two simultaneous longitudinal modes with a relatively wide tuning range from 5.83 MHz to 0,02 THz are obtained when the Nd:YAG laser is operated at moderate output power of about 120 roW. The mode structure of this configuration is modeled and simulated. Computer-generated diagrams are also presented schematically and compared with the experimental results.展开更多
We present a compact Tm-doped fiber laser(TDFL)to generate pulse bursts at 1.92μm based on phase and intensity modulations.A phase modulator(PM)and an intensity modulator(IM)were included in the linear TDFL cavity to...We present a compact Tm-doped fiber laser(TDFL)to generate pulse bursts at 1.92μm based on phase and intensity modulations.A phase modulator(PM)and an intensity modulator(IM)were included in the linear TDFL cavity to perform the simultaneous active intracavity phase and intensity modulation.Stable pulse bursts have been achieved with tunable repetition rate in the range of 36–44 kHz(modulated by the PM)and duration of about 9.6μs.The repetition rate of the individual pulse in a burst is about 9 MHz(modulated by the IM),and the pulse width is about 6 ns.By changing the IM signal’s repetition rate and duty cycle,different individual pulse shapes are obtained with pulse durations between 6 and 34 ns.展开更多
This work demonstrates the Nd:YAG waveguide laser as an efficient platform for the bio-sensing of dextrose solutions and tumor cells. The waveguide was fabricated in an Nd:YAG crystal with the cooperation of ultrafast...This work demonstrates the Nd:YAG waveguide laser as an efficient platform for the bio-sensing of dextrose solutions and tumor cells. The waveguide was fabricated in an Nd:YAG crystal with the cooperation of ultrafast laser writing and ion irradiation. The laser oscillation in the Nd:YAG waveguide is ultrasensitive to the external environment of the waveguide. Even a weak disturbance leads to a large variation of the output power of the laser.According to this feature, an Nd:YAG waveguide coated with graphene and WSe_2 layers is used as substrate for the microfluidic channel. When the microflow crosses the Nd:YAG waveguide, the laser oscillation in the waveguide is disturbed and induces fluctuation of the output laser. According to the fluctuation, the microflow is detected with a sensitivity of 10 mW/RIU.展开更多
High-order harmonic generation(HHG)is currently utilized for developing compact table-top radiation sources to provide highly coherent extreme ultraviolet(XUV)and soft X-ray pulses;however,the low repetition rate of f...High-order harmonic generation(HHG)is currently utilized for developing compact table-top radiation sources to provide highly coherent extreme ultraviolet(XUV)and soft X-ray pulses;however,the low repetition rate of fundamental lasers,which is typically in the multi-kHz range,restricts the area of application for such HHG-based radiation sources.Here,we demonstrate a novel method for realizing a MHz-repetition-rate coherent XUV light source by utilizing intracavity HHG in a mode-locked oscillator with an Yb:YAG thin disk laser medium and a 100-m-long ring cavity.We have successfully implemented HHG by introducing two different rare gases into two separate foci and picking up each HH beam.Owing to the two different HH beams generated from one cavity,this XUV light source will open a new route to performing a time-resolved measurement with an XUV-pump and XUV-probe scheme at a MHzrepetition rate with a femtosecond resolution.展开更多
A Kerr-lens, mode-locked YVO4∕Nd:YVO4laser coupled with an acousto-optic modulator(AOM) Q-switching near1064 nm was employed to pump an intracavity KTi OPO4(KTP) optical parametric oscillator. A subnanosecond sig...A Kerr-lens, mode-locked YVO4∕Nd:YVO4laser coupled with an acousto-optic modulator(AOM) Q-switching near1064 nm was employed to pump an intracavity KTi OPO4(KTP) optical parametric oscillator. A subnanosecond signal wave near 1572 nm with low repetition rate was realized. At an AOM repetition rate of 8 kHz, the maximum output power was 165 mW. The highest average pulse energy, the shortest duration, and the highest peak power of a mode-locking signal pulse were estimated to be ~10.3 μJ, ~120 ps, and ~82 kW, respectively.展开更多
The rate equations for the intracavity-frequency-doubled quasi-three-level lasers are developed. By normalizing the related parameters, it is shown that the general solution to the rate equations is dependent upon fou...The rate equations for the intracavity-frequency-doubled quasi-three-level lasers are developed. By normalizing the related parameters, it is shown that the general solution to the rate equations is dependent upon four dimensionless parameters: the normalized reabsorption loss, the pump to laser-mode size ratio, the normalized pump level, and a parameter written as nSHG, which is related to the ability of the nonlinear crystal to convert the fundamental to the second harmonic. By numerically solving these rate equations, a group of general curves are obtained to express the relations between the solution and the four dimensionless parameters.展开更多
We demonstrate a widely tunable near-infrared source from 767 nm to 874 nm generated by the intracavity second harmonic generation (SHG) in an optical parametric oscillator pumped by a Yb:LYSO solid-state laser. Th...We demonstrate a widely tunable near-infrared source from 767 nm to 874 nm generated by the intracavity second harmonic generation (SHG) in an optical parametric oscillator pumped by a Yb:LYSO solid-state laser. The home-made Yb:LYSO oscillator centered at 1035 nm delivers an average power of 2 W and a pulse duration as short as 351 fs. TWo MgO doped periodically poled lithium niobates (MgO:PPLN) with grating periods of 28.5-31.5 μm in steps of 0.5 μm and 19.5-21.3μm in steps of 0.2 μm are used for the OPO and intracavity SHG, respectively. The maximum average output power of 180 mW at 798 nm was obtained and the output pulses have pulse duration of 313 fs at 792 nm if a sech2-pulse shape was assumed. In addition, tunable signal femtosecond pulses from 1428 nm to 1763 nm are also realized with the maximum average power of 355 mW at 1628 nm.展开更多
基金Project supported in part by the National Natural Science Foundation of China (Grant Nos 10474071, 60637010, 60671036 and60278001)Tianjin Applied Fundamental Research Project, China (07JCZDJC05900)
文摘This paper reports a continuous-wave (CW) mid-infrared intracavity singly resonant optical parametric oscillator based on periodically poled lithium niobate (PPLN) pumped by a diode-end-pumped CW Nd:YVO4 laser. Considering the thermal lens effects, it adopted an optical ballast lens and the near-concentric cavity for better operation. At the PPLN's grating period of 28.5 μm and the temperature of 140℃, the maximum idler output power of 155 mW at 3.86 μm has been achieved when the 808 nm pump power is 8.5 W, leading to an optical-to-optical conversion efficiency of 1.82%.
基金Project supported partly by the National Natural Science Foundation of China (Grant Nos 60637010 and 60671036)the National Basic Research Program of China (Grant No 2007CB310403)the Tianjin Applied Fundamental Research Project, China(Grant No 07JCZDJC05900)
文摘In this paper we report on a continuous-wave (CW) intracavity singly resonant optical parametric oscillator (ICSRO) based on periodically poled LiNbO3 (PPLN) pumped by a diode-end-pumped CW Nd:YVO4 laser. Considering the thermal lens effects and diffraction loss, an optical ballast lens and a near-concentric cavity are adopted for better operation. Through varying the grating period and the temperature, the tunable signal output from 1406 nm to 1513 nm is obtained. At a PPLN grating period of 29 pm and a temperature of 413 K, a maximum signal output power of 820 mW at 1500 nm is achieved when the 808 nm pump power is 10.9 W, leading to an optical-to-optical conversion efficiency of 7.51%.
基金Project supported by the National Key R&D Program of China(Grant No.2016YFA0301401)
文摘We demonstrated a continuous wave(cw) single-frequency intracavity frequency-doubled Nd:YVO_4/LBO laser with 532 nm output of 7.5 W and 1.06 μm output of 3.1 W, and low intensity noise in audio frequency region.To suppress the intensity noise of the high power 532 nm laser, a laser frequency locking system and a feedback loop based on a Mach-Zehnder interferometer were designed and used.The influences of the frequency stabilization and the crucial parameters of the MZI, such as the power splitting ratio of the beam splitters and the locking state of the MZI, on the intensity noise of the 532 nm laser were investigated in detail.After the experimental optimizations, the laser intensity noise in the frequency region from 0.4 kHz to 10 kHz was significantly suppressed.
基金Supported by the National Natural Science Foundation of China under Grant No 60821004the National High-tech R&D Program of China(2011AA030203).
文摘We demonstrate a tunable continuous-wave single frequency intracavity frequency-doubled Ti:sapphire laser.The highest output power of 280 mW at 461.62 nm is obtained by employing a type-I phase-matched BIBO crystal and the peak-to-peak fluctuation of the power is less than±1%within three hours.The frequency stability is better than±2.22 MHz over 10 min when the laser is locked to a confocal Fabry–Perot cavity.A three-plate birefringent filter allows for the tunable range from 457 nm to 467 nm,which covers the absorption line of the strontium atoms(460.86 nm).
基金Project supported by the National Natural Science Foundation of China (Grant No 60478017), the Science and Technology Development Program of Shandong Province, China and the Scientific Research Starting Foundation for Returned 0verseas Chinese Scholars, Ministry of Education, China.
文摘We present a model of passively Q-switched Raman lasers by utilizing the rate equations. The intracavity fun-damental photon density, Raman photon density and the initial population-inversion density of the gain medium are assumed to be of Gaussian spatial distributions. These rate equations are normalized by introducing some synthetic parameters and solved numerically, and a group of general curves are generated. Prom these curves we can understand the dependence of the Raman laser pulse characteristics on the parameters about the pumping, the gain medium, the Raman medium and the resonator. An illustrative calculation for a passively Q-switched Nd^3+:GdVO4 self-Raman laser is presented to demonstrate the usage of the curves and related formulas.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 10874237 and 61205130)the Knowledge Innovation Program of Chinese Academy of Sciences (Grant No. KJCX2-YW-N36)
文摘We demonstrated experimentally a synchronously pumped intracavity frequency-doubled femtosecond optical para- metric oscillator (OPO) using a periodically-poled lithium niobate (PPLN) as the nonlinear material in combination with a lithium triborate (LBO) as the doubling crystal. A Kerr-lens-mode-locked (KLM) Ti:sapphire oscillator at the wavelength of 790 nm was used as the pump source, which was capable of generating pulses with a duration as short as 117 fs. A tunable femtosecond laser covering the 624-672 nm range was realized by conveniently adjusting the OPO cavity length. A maximum average output power of 260 mW in the visible range was obtained at the pump power of 2.2 W, with a typical pulse duration of 205 fs assuming a sech2 pulse profile.
基金Supported by the National Key Basic Research Program of China under Grant Nos 2013CB933304 and 2014CB643904the National Natural Science Foundation of China under Grant Nos 61435012 and 61274125the Strategic Priority Research Program(B) of Chinese Academy of Sciences under Grant No XDB01010200
文摘A four-wavelength Bragg reflection waveguide edge emitting diode based on intracavity spontaneous parametric down-conversion and four-wave mixing (FWM) processes is made. The structure and its tuning characteris- tic are designed by the aid of FDTD mode solution. The laser structure is grown by molecular beam epitaxy and processed to laser diode through the semiconductor manufacturing technology. Fourier transform infrared spectroscopy is applied to record wavelength information. Pump around 1.071 μm, signal around 1.77μm, idler around 2.71 μm and FWM signal around 1.35μm are observed at an injection current of 560mA. The influ- ences of temperature, carrier density and pump wavelength on tuning characteristic are shown numerically and experimentally.
基金supported by the National Natural Science Foundation of China(No.62175181)。
文摘A high efficiency,low threshold,high repetition rate H-βFraunhofer line light at 486.1 nm was demonstrated.A high-efficiency KTP optical parametric oscillator was achieved by double-pass pumping with a high-maturity 5 kHz 532 nm laser.Thanks to the efficient intracavity frequency doubling of the circulating signal wave by a BIBO crystal,the threshold pump power of the 486.1 nm output was 0.9 W,and the maximum output power of 1.6 W was achieved under the pump power of7.5 W.The optical–optical conversion efficiency was 21.3%,with the pulse duration of 45.2 ns,linewidth of~0.12 nm,and beam quality factor M~2 of 2.83.
基金National Basic Research Program of China(973)(2014CB339802,2015CB755403)National key research and development projects(2016YFC0101001)+5 种基金National Key Technology R&D Program of China(2014BAI04B05,2015BAI01B01)National Natural Science Foundation of China(NSFC)(61107086,61471257,81402067)Natural Science Foundation of Tianjin City(14JCQNJC02200)Postdoctoral Science Foundation of Chongqing(Xm2016021)Joint Incubation Project of Southwest Hospital(SWH2016LHJC-04,SWH2016LHJC-01)Science and Technology Support Program of Tianjin(13ZCZDSF02300)
文摘We have demonstrated a high-average-power,high-repetition-rate optical terahertz(THz)source based on difference frequency generation(DFG)in the GaSe crystal by using a near-degenerate 2μm intracavity KTP optical parametric oscillator as the pump source.The power of the 2μm dual-wavelength laser was up to 12.33 W with continuous tuning ranges of 1988.0–2196.2 nm/2278.4–2065.6 nm for two waves.Different GaSe cystal lengths have been experimentally investigated for the DFG THz source in order to optimize the THz output power,which was in good agreement with the theoretical analysis.Based on an 8 mm long GaSe crystal,the THz wave was continuously tuned from 0.21 to 3 THz.The maximum THz average power of 1.66μW was obtained at repetition rate of 10 kHz under 1.48 THz.The single pulse energy amounted to 166 pJ and the conversion efficiency from 2 μm laser to THz output was 1.68×10^(-6).The signal-to-noise ratio of the detected THz voltage was 23 dB.The acceptance angle of DFG in the GaSe crystal was measured to be 0.16°.
基金National Natural Science Foundation of China(NSFC)(61805225,11804323)
文摘A wavelength-tunable and dual-wavelength mode-locking operation is achieved in an Er-doped fiber laser using a hybrid no-core fiber graded index multimode fiber as the saturable absorber. In the tuning operation, continuously wavelength-tunable pulses with a tuning range of 46.7 nm, stable 3-dB bandwidth of around 5 nm, and pulse duration of ~850 fs are obtained by increasing the intracavity loss of a variable optical attenuator. In the dual-wavelength operation, the two solitons at different wavelengths demonstrate the characteristics of mutual coherence. By increasing the intracavity loss, the spectral spacing can be tuned from 11 to 33.01 nm while maintaining the coherence of the solitons. Such coherent solitons have high potential for applications in dual-comb frequency and multicolor pulses in nonlinear microscopy.
文摘A quasi-continuous-wave intracavity frequency-doubled Nd:YAG laser which operates at 660 nm is studied. By using a flat-flat laser cavity, 2 Kr-lamps, KTP crystal and an acousto-optically Q-switch, 2-W output power at 660 nm is obtained. The relationship between laser cavity length and output power is analyzed.
基金This work was partly supported by the National Natural Science Foundation of China the Research Fund for the Doctoral Program of Higher Education of the Ministry of Education of China the Science Foundation of Shandong Province.
文摘The spatial distributions of the pumping,the population inversion density,and the intracavity photon densities of the fundamental and the second harmonic are taken into account in the rate equations of the intracavity-frequency-doubled cw lasers.By normalizing the related parameters,it is shown that the general solution of these space-dependent rate equations is dependent upon three dimensionless parameters:the pump to laser-mode size ratio,the normalized pump level,and a parameter written as ηSHG,which is related to the ability of the nonlinear crystal to convert the fundamental to the second harmonic.By numerically solving these rate equations,a group of general curves are obtained to express the relations between the solution and the three dimensionless parameters.In addition,the optimal pump to laser-mode size ratio and the optimal ηSHG are determined.A comparison with the result obtained under the plane-wave approximation is also given.
基金supported by the National Natural Science Foundation of China under Grant Nos.61575112 and 61308121
文摘Cavity quantum electrodynamics (QED) is mainly re- searching the interaction process with a coherent atomic medium placed inside an optical resonant cavity, and has been of great interest in recent years. A well-known cavity- QED effect is the vacuum Rabi splitting or normal-mode splitting phenomenon that is under the strong coupling condition,
文摘In this letter, a thin slab of glass is used as Fabry-Perot etalon inside a cavity of a continuous wave (CW) Nd:YAG laser to change the behavior of its output longitudinal modes. The slab etalon is used as tuning element when it turns around the laser cavity axis. Two simultaneous longitudinal modes with a relatively wide tuning range from 5.83 MHz to 0,02 THz are obtained when the Nd:YAG laser is operated at moderate output power of about 120 roW. The mode structure of this configuration is modeled and simulated. Computer-generated diagrams are also presented schematically and compared with the experimental results.
基金the Graduate Student Innovation Foundation of National University of Defense Technology(Grant No.B130704)National Natural Science Foundation of China(Grant No.61322505)the Program for New Century Excellent Talents in University,and the Hunan Provincial Innovation Foundation for Postgraduate.
文摘We present a compact Tm-doped fiber laser(TDFL)to generate pulse bursts at 1.92μm based on phase and intensity modulations.A phase modulator(PM)and an intensity modulator(IM)were included in the linear TDFL cavity to perform the simultaneous active intracavity phase and intensity modulation.Stable pulse bursts have been achieved with tunable repetition rate in the range of 36–44 kHz(modulated by the PM)and duration of about 9.6μs.The repetition rate of the individual pulse in a burst is about 9 MHz(modulated by the IM),and the pulse width is about 6 ns.By changing the IM signal’s repetition rate and duty cycle,different individual pulse shapes are obtained with pulse durations between 6 and 34 ns.
基金National Natural Science Foundation of China(NSFC)(11535008,11775136)Young Scholars Program of Shandong University(SDU)(2015WLJH20)
文摘This work demonstrates the Nd:YAG waveguide laser as an efficient platform for the bio-sensing of dextrose solutions and tumor cells. The waveguide was fabricated in an Nd:YAG crystal with the cooperation of ultrafast laser writing and ion irradiation. The laser oscillation in the Nd:YAG waveguide is ultrasensitive to the external environment of the waveguide. Even a weak disturbance leads to a large variation of the output power of the laser.According to this feature, an Nd:YAG waveguide coated with graphene and WSe_2 layers is used as substrate for the microfluidic channel. When the microflow crosses the Nd:YAG waveguide, the laser oscillation in the waveguide is disturbed and induces fluctuation of the output laser. According to the fluctuation, the microflow is detected with a sensitivity of 10 mW/RIU.
基金the support from the special postdoctoral researcher program of RIKENthe financial support from Grants-in-Aid for Scientific Research Nos.26247068,26220606,and 19H05628+2 种基金supported by the Photon Frontier Network Programthe Special Coordination Funds for Promoting Science and Technologythe Center of Innovation Science program of the Ministry of Education,Culture,Sports,Science and Technology.
文摘High-order harmonic generation(HHG)is currently utilized for developing compact table-top radiation sources to provide highly coherent extreme ultraviolet(XUV)and soft X-ray pulses;however,the low repetition rate of fundamental lasers,which is typically in the multi-kHz range,restricts the area of application for such HHG-based radiation sources.Here,we demonstrate a novel method for realizing a MHz-repetition-rate coherent XUV light source by utilizing intracavity HHG in a mode-locked oscillator with an Yb:YAG thin disk laser medium and a 100-m-long ring cavity.We have successfully implemented HHG by introducing two different rare gases into two separate foci and picking up each HH beam.Owing to the two different HH beams generated from one cavity,this XUV light source will open a new route to performing a time-resolved measurement with an XUV-pump and XUV-probe scheme at a MHzrepetition rate with a femtosecond resolution.
基金supported by the National Natural Science Foundation of China (61378022)the National Natural Science Foundation of China for Youths (61205145)+2 种基金the Fundamental Research Funds of Shandong University (2014JC032)the China Postdoctoral Science Foundation (2013M541901)Independent Innovation Foundation of Shandong University, IIFSDU (2013HW013 and 2014TB011)
文摘A Kerr-lens, mode-locked YVO4∕Nd:YVO4laser coupled with an acousto-optic modulator(AOM) Q-switching near1064 nm was employed to pump an intracavity KTi OPO4(KTP) optical parametric oscillator. A subnanosecond signal wave near 1572 nm with low repetition rate was realized. At an AOM repetition rate of 8 kHz, the maximum output power was 165 mW. The highest average pulse energy, the shortest duration, and the highest peak power of a mode-locking signal pulse were estimated to be ~10.3 μJ, ~120 ps, and ~82 kW, respectively.
文摘The rate equations for the intracavity-frequency-doubled quasi-three-level lasers are developed. By normalizing the related parameters, it is shown that the general solution to the rate equations is dependent upon four dimensionless parameters: the normalized reabsorption loss, the pump to laser-mode size ratio, the normalized pump level, and a parameter written as nSHG, which is related to the ability of the nonlinear crystal to convert the fundamental to the second harmonic. By numerically solving these rate equations, a group of general curves are obtained to express the relations between the solution and the four dimensionless parameters.
基金supported by the National Key Basic Research Program of China(Grant No.2013CB922402)the National Key Scientific Instruments Development Program of China(Grant No.2012YQ120047)+1 种基金the National Natural Science Foundation of China(Grant Nos.61205130 and 11174361)the Key Deployment Project of Chinese Academy of Sciences(Grant No.KJZD-EW-L11-03)
文摘We demonstrate a widely tunable near-infrared source from 767 nm to 874 nm generated by the intracavity second harmonic generation (SHG) in an optical parametric oscillator pumped by a Yb:LYSO solid-state laser. The home-made Yb:LYSO oscillator centered at 1035 nm delivers an average power of 2 W and a pulse duration as short as 351 fs. TWo MgO doped periodically poled lithium niobates (MgO:PPLN) with grating periods of 28.5-31.5 μm in steps of 0.5 μm and 19.5-21.3μm in steps of 0.2 μm are used for the OPO and intracavity SHG, respectively. The maximum average output power of 180 mW at 798 nm was obtained and the output pulses have pulse duration of 313 fs at 792 nm if a sech2-pulse shape was assumed. In addition, tunable signal femtosecond pulses from 1428 nm to 1763 nm are also realized with the maximum average power of 355 mW at 1628 nm.