Interference filter-stabilized external cavity diode lasers （ECDLs） have properties of simple configurations, high sta- bilities, and narrow linewidths. However, the interference filter used in common ECDL designs r...Interference filter-stabilized external cavity diode lasers （ECDLs） have properties of simple configurations, high sta- bilities, and narrow linewidths. However, the interference filter used in common ECDL designs requires an ultra-narrow bandwidth （about 0.3 nm） to achieve mode selection, that is considerably expensive and not yet available for a wide range of wavelengths. In this paper, a robust ECDL using an available broad bandwidth （about 4 nm） interference filter as the wavelength discriminator is constructed and tested. The ECDL demonstrated a narrow Lorentzian fitted linewidth of 95 kHz and a spectral purity of 2.9 MHz. The long-term frequency stability of the ECDL reaches 5.59 x 10 12.展开更多
Narrow linewidth light source is a prerequisite for high-performance coherent optical communication and sensing.Waveguide-based external cavity narrow linewidth semiconductor lasers(WEC-NLSLs)have become a competitive...Narrow linewidth light source is a prerequisite for high-performance coherent optical communication and sensing.Waveguide-based external cavity narrow linewidth semiconductor lasers(WEC-NLSLs)have become a competitive and attractive candidate for many coherent applications due to their small size,volume,low energy consumption,low cost and the ability to integrate with other optical components.In this paper,we present an overview of WEC-NLSLs from their required technologies to the state-of-the-art progress.Moreover,we highlight the common problems occurring to current WEC-NLSLs and show the possible approaches to resolving the issues.Finally,we present the possible development directions for the next phase and hope this review will be beneficial to the advancements of WEC-NLSLs.展开更多
A 60-mW solid-state deep ultraviolet(DUV)laser at 193 nm with narrow linewidth is obtained with two stages of sum frequency generation in LBO crystals.The pump lasers,at 258 and 1553 nm,are derived from a homemade Yb-...A 60-mW solid-state deep ultraviolet(DUV)laser at 193 nm with narrow linewidth is obtained with two stages of sum frequency generation in LBO crystals.The pump lasers,at 258 and 1553 nm,are derived from a homemade Yb-hybrid laser employing fourth-harmonic generation and Er-doped fiber laser,respectively.The Yb-hybrid laser,finally,is power scaling by a 2 mm×2 mm×30 mm Yb:YAG bulk crystal.Accompanied by the generated 220-mW DUV laser at 221 nm,the 193-nm laser delivers an average power of 60 mW with a pulse duration of 4.6 ns,a repetition rate of 6 kHz,and a linewidth of∼640 MHz.To the best of our knowledge,this is the highest power of 193-and 221-nm laser generated by an LBO crystal ever reported as well as the narrowest linewidth of 193-nm laser by it.Remarkably,the conversion efficiency reaches 27%for 221 to 193 nm and 3%for 258 to 193 nm,which are the highest efficiency values reported to date.We demonstrate the huge potential of LBO crystals for producing hundreds of milliwatt or even watt level 193-nm laser,which also paves a brand-new way to generate other DUV laser wavelengths.展开更多
We propose and demonstrate a novel single-longitudinal-mode(SLM) erbium-doped fiber laser(EDFL) capable of operating at fixed-wavelength lasing mode with a tunable range more than 54 nm, an ultra-narrow linewidth of 4...We propose and demonstrate a novel single-longitudinal-mode(SLM) erbium-doped fiber laser(EDFL) capable of operating at fixed-wavelength lasing mode with a tunable range more than 54 nm, an ultra-narrow linewidth of 473 Hz and an ultra-high optical signal-to-noise ratio(OSNR) more than 72 dB, or operating at wavelength-swept mode with tunable sweep rate of 10—200 Hz and a sweep range more than 50 nm. The excellent features mainly benefit from a triple-ring subring cavity constructed by three optical couplers nested one another and a fiber Fabry-Pérot tunable filter which can be driven by a constant voltage or a periodic sweep voltage for fixed or wavelength-swept operation, respectively. The proposed EDFL has potential applications in high-resolution spectroscopy and fiber optic sensing.展开更多
Stimulated Brillouin scattering(SBS)-induced mode distortion(MD)in high power narrow linewidth fiber amplifiers has been implemented,and the origin has been investigated from the aspect of the evolution of the optical...Stimulated Brillouin scattering(SBS)-induced mode distortion(MD)in high power narrow linewidth fiber amplifiers has been implemented,and the origin has been investigated from the aspect of the evolution of the optical spectrum,spatial beam profiles,and temporal-frequency domain characteristics.展开更多
Lasers with the gain medium of gas,liquid,semiconductor,and solid could generate coherent light with rather narrow spectral linewidth,which play an important role in the fields of communication,measurement,sensing,and...Lasers with the gain medium of gas,liquid,semiconductor,and solid could generate coherent light with rather narrow spectral linewidth,which play an important role in the fields of communication,measurement,sensing,and so on.Although free electron lasers have been realized with their unique advantages,they face challenges in narrowing the spectral linewidth,owing to electron energy fluctuation,Coulomb effect,and other mechanism.Here we demonstrate the superradiant Smith-Purcell radiation(S-SPR)in terahertz frequency band with ultra-narrow and continuously tunable linewidth in a compact device.By proposing a new effect of pump-induced stimulated S-SPR(PIS-SPR),the spectral linewidth could be reduced to 0.3 kHz@291.7 GHz,which is about two–six orders of magnitude narrower compared with those obtained by accelerators and other electron devices.Meanwhile,the wide range of continuously tunable spectral linewidth spanning 0.3–900 kHz is observed for the first time.This work provides a way to greatly narrow the spectral linewidth of free electron radiation and to achieve high-order harmonic of S-SPR in a compact device,and offers a platform to study the interaction between free electron bunches and different micro-&nano-structures.展开更多
Optically pumped lasers based on solution-processed thin-film gain media have recently emerged as low-cost,broadly tunable,and versatile active photonics components that can fit any substrate and are useful for,e.g.,c...Optically pumped lasers based on solution-processed thin-film gain media have recently emerged as low-cost,broadly tunable,and versatile active photonics components that can fit any substrate and are useful for,e.g.,chemo-or biosensing or visible spectroscopy.Although single-mode operation has been demonstrated in various resonator architectures with a large variety of gain media-including dye-doped polymers,organic semiconductors,and,more recently,hybrid perovskites-the reported linewidths are typically on the order of a fraction of a nanometer or broader,i.e.,the coherence lengths are no longer than a few millimeters,which does not enable high-resolution spectroscopy or coherent sensing.The linewidth is fundamentally constrained by the short photon cavity lifetime in the standard resonator geometries.We demonstrate here a novel structure for an organic thin-film solid-state laser that is based on a vertical external cavity,wherein a holographic volume Bragg grating ensures both spectral selection and output coupling in an otherwise very compact(,cm3)design.Under short-pulse(0.4 ns)pumping,Fourier-transform-limited laser pulses are obtained,with a full width at half-maximum linewidth of 900 MHz(1.25 pm).Using 20-ns-long pump pulses,the linewidth can be further reduced to 200 MHz(0.26 pm),which is four times above the Fourier limit and corresponds to an unprecedented coherence length of 1m.The concept is potentially transferrable to any type of thin-film laser and can be ultimately made tunable;it also represents a very compact alternative to bulky grating systems in dye lasers.展开更多
Yb-doped fiber laser(YDFL) is a promising kind of laser source due to high efficiency, excellent beam quality, robust configuration, diverse applications and so on. The progress of large-mode-area double cladding acti...Yb-doped fiber laser(YDFL) is a promising kind of laser source due to high efficiency, excellent beam quality, robust configuration, diverse applications and so on. The progress of large-mode-area double cladding active fiber and high power laser diodes have been continuously promoting the power scaling of the YDFLs. However, the further power scaling is blocked by some physic issues including nonlinear effect, thermal-induced mode instability(MI), optical damage and so forth. So, newlydesigned fibers with special structures are invented to address or relieve these limitations. The tapered fiber, which has changed mode area along its longitudinal direction, has been demonstrated to benefit suppressing the nonlinear effect, especially the stimulated Brillouin scattering(SBS) effect. In this paper, we will review the previous work done to explore the advantages of the tapered fiber for high power output, and then for the first time to our knowledge, demonstrate an all-fiberized high power narrow linewidth fiber laser based on a homemade tapered Yb-doped fiber(T-YDF). As a result, an output power of 260 W with a narrow linewidth of ~2 GHz is obtained, with SBS effectively suppressed owing to gradually increased mode area of the T-YDF as well as continuously changed Brillouin frequency shift dependent on the core diameter. Further power scaling is limited by MI, and the features of MI are studied in detail. It is pointed out that, the MI seems the primary and durative limitation factor of the tapered fiber amplifier for high power narrow linewidth output due to the gradually increased effective numerical aperture(NA) and the excitation of the high-order modes, even although it has the advantage to reduce other nonlinear effects. At last,worthwhile discussion about the optimization of the T-YDF and the whole fiber laser system for both SBS and MI suppression is conducted based on the previous and our results. It is concluded that the small diameter at the small-diameter end and low optical NA are preferred in the design of a T-YDF to ensure good beam quality and improve the MI threshold. The good splicing quality and proper coiling or bend state are also necessary.展开更多
We report here a high-power, wavelength tunable and narrow linewidth 1.5 μm all-fiber laser amplifier based on a tunable diode laser and Er-Yb co-doped fibers. The laser wavelength can be precisely tuned from 1535 nm...We report here a high-power, wavelength tunable and narrow linewidth 1.5 μm all-fiber laser amplifier based on a tunable diode laser and Er-Yb co-doped fibers. The laser wavelength can be precisely tuned from 1535 nm to 1580 nm, which covers many absorption lines of mid-infrared laser gases, such as C2 H2, HCN, CO, and HI. The maximum laser power is >11 W, and the linewidth is about 200–300 MHz, which is close to the absorption linewidth of the above-mentioned gases. This work provides a suitable pump source for high-power wavelength tunable mid-infrared fiber gas lasers based on low-loss hollow-core fibers.展开更多
A narrow linewidth laser configuration based on distributed feedback fiber lasers （DFB-FL） with eight wavelengths in the international telecommunication union （ITU） grid is presented and realized. In this laser co...A narrow linewidth laser configuration based on distributed feedback fiber lasers （DFB-FL） with eight wavelengths in the international telecommunication union （ITU） grid is presented and realized. In this laser configuration, eight phase-shifted gratings in series are bidirectionally pumped by two 980-nm laser diodes （LDs）. The final laser output with over 10-mW power for each wavelength can be obtained, and the maximum power difference within eight wavelengths is 1.2 dB. The laser configuration with multiple wavelengths and uniform power outputs can be very useful in large scaled optical fiber hydrophone fields.展开更多
A whispering gallery mode resonator(WGMR)filter can narrow laser linewidth while significantly changing the output power characteristics of fiber laser system.It is found that traditional laser output power model is i...A whispering gallery mode resonator(WGMR)filter can narrow laser linewidth while significantly changing the output power characteristics of fiber laser system.It is found that traditional laser output power model is invalid.We report a correction model of a narrow linewidth fiber laser filtered with a WGMR to analyze its power.We believe that the loss of the laser system and the threshold gain increase caused by the WGMR filter lead to the predominate amplified spontaneous emission during the original laser period.According to that,we assume the correction coefficient is an exponential decay related to the Er-doped fiber length in the large loss situation,and we verify it experimentally.As a result,the correction model is valid for WGMR-filtered fiber laser.展开更多
We investigate the resonance fluorescence spectrum of an atomic three-level ladder system driven by two laser fields. We show that such a system emulates to a large degree a V-type atom with parallel dipole moments-th...We investigate the resonance fluorescence spectrum of an atomic three-level ladder system driven by two laser fields. We show that such a system emulates to a large degree a V-type atom with parallel dipole moments-the latter being a system that exhibits spontaneously generated coherence and can display ultrasharp spectral lines. We find a suitable energy scheme in a SSRb atom and experimentally observe the narrowing of the central peak in a rubidium atomic beam. The corresponding spectrum can convindngiy demonstrate the existence of spontaneously generated coherence.展开更多
We present a quantum-theoretical treatment of cavity linewidth narrowing with intracavity electromagnetically in- duced transparency （EIT）. By means of intracavity EIT, the photons in the cavity are in the form of c...We present a quantum-theoretical treatment of cavity linewidth narrowing with intracavity electromagnetically in- duced transparency （EIT）. By means of intracavity EIT, the photons in the cavity are in the form of cavity polaritons： bright-state polariton and dark-state polariton. Strong coupling of the bright-state polariton to the excited state induces an effect known as vacuum Rabi splitting, whereas the dark-state polariton decoupled from the excited state induces a narrow cavity transmission window. Our analysis would provide a quantum theory of linewidth narrowing with a quantum field pulse.展开更多
The output characteristics of a narrow linewidth, no-gain competition, dual-wavelength solid-state laser using an intra-cavity pumped method are reported. This system consists of an intra-cavity pumped Nd:YVO4 laser e...The output characteristics of a narrow linewidth, no-gain competition, dual-wavelength solid-state laser using an intra-cavity pumped method are reported. This system consists of an intra-cavity pumped Nd:YVO4 laser emitting at 1064 nm, using a 912 nm Nd:GdVO4 laser. A Fabry-Perot etalon is used to compress the linewidth that located at the common cavity of 912 nm and 1064 nm laser. Theoretical analysis and experimental verification were carried out. When the pump power is 32.8 W, the output of 912 nm and 1064 nm theoretical value is 0.036 W and 0.046 W, and the experimental value is 0.017 W and 0.016 W, respectively. The change trend of the theoretical simulated output power value was the same as the actual measured value in the experiment. In addition to this, the experimental measurement shows when the etalon with an angle of 15?, corresponding minimum linewidths were 0.284 nm and 0.627 nm, respectively.展开更多
Two Nd：YAG lasers operating at 1064 nm are separately servo-locked to two vertically mounted ultra-stable cavities. The optical heterodyne beat between two cavity-stabilized lasers shows that the linewidth of each la...Two Nd：YAG lasers operating at 1064 nm are separately servo-locked to two vertically mounted ultra-stable cavities. The optical heterodyne beat between two cavity-stabilized lasers shows that the linewidth of each laser reaches 2 Hz and the average frequency drift reduces to less than 1 Hz/s.展开更多
This study demonstrates a mid-infrared narrow-linewidth tandem optical parametric oscillator(TOPO)based on dual Mg O:PPLN crystals.A secondary-pumping technique with a periodically poled MgO:PPLN crystal is employed t...This study demonstrates a mid-infrared narrow-linewidth tandem optical parametric oscillator(TOPO)based on dual Mg O:PPLN crystals.A secondary-pumping technique with a periodically poled MgO:PPLN crystal is employed to achieve threewavelength mid-infrared laser outputs at 2.70,3.45,and 4.25μm.A 1064 nm ytterbium-doped fiber laser is employed as the pump source,with a single laser output sequentially pumping two MgO:PPLN crystals which have period lengths of 30.44 and31.89μm,respectively.The synchronous three-wavelength mid-infrared laser output is achieved through two optical parametric oscillation(OPO)processes and one TOPO process.The processes are as follows:1.06μm→1.53μm+3.45μm;1.06μm→1.75μm+2.70μm;1.53μm→2.40μm+4.25μm.The linewidth of the signal light is compressed using a1 mm thick Fabry-Perot(F-P)etalon,reducing the linewidths of 2.70,3.45,and 4.25μm from 3.03,7.83,and 1.20 nm to0.32,0.60,and 0.55 nm,respectively.The associated output powers are 0.681,1.342,and 0.098 W.展开更多
Ytterbium ion(Yb^(3+))-doped lasers are widely used in precision machining and precision measurement fields because of their high efficiency and high power,which are primarily based on solid-state lasers and fiber las...Ytterbium ion(Yb^(3+))-doped lasers are widely used in precision machining and precision measurement fields because of their high efficiency and high power,which are primarily based on solid-state lasers and fiber lasers.Here,we demonstrate an on-chip Yb^(3+)-doped thin-film lithium niobate(Yb:TFLN)Fabry-Perot microcavity laser.We achieve single-frequency laser operation at 1030 and 1060 nm with a side-mode suppression ratio above 30 dB,an emission linewidth below 40 pm,and an output power up to 1.5 mW at 1060 nm and 0.3 mW at 1030 nm.In addition,using the electro-optic effect of lithium niobate,we achieve a laser tuning efficiency of 4 pm/V.This work opens the path to on-chip high-power and mode-locked ultrafast laser output.展开更多
This paper introduces a high single-pulse energy,narrow-linewidth mid-infrared self-optical parametric oscillator(midIR SOPO)with a cavity length of 120 mm and a Nd:Mg O:PPLN crystal.To achieve high single-pulse energ...This paper introduces a high single-pulse energy,narrow-linewidth mid-infrared self-optical parametric oscillator(midIR SOPO)with a cavity length of 120 mm and a Nd:Mg O:PPLN crystal.To achieve high single-pulse energy and high peak power in mid-IR light sources,a LiNbO3 electro-optic Q-switch(EOQ)is introduced for the first time in a midIR SOPO.A narrow-linewidth EOQ-SOPO rate equation is formulated,and experiments are conducted using a single Fabry–Pérot etalon.At a 500μs pump pulse width,a 4.71 m J single-pulse idler light at 3838.2 nm is achieved,with a linewidth of 0.412 nm,single-pulse width of 4.78 ns and peak power of 985 k W.At 200μs,the idler light at 3845.2 nm exhibits a minimum linewidth of 0.212 nm.展开更多
基金Project supported by the Foundation of Based Technology of China(Grant No.YXBGD20151JL01)the National Natural Science Foundation of China(Grant Nos.61376049,61604007,11674016,61378058,61575008,and 61574011)+1 种基金the Natural Science Foundation of Beijing City,China(Grant Nos.4172009 and4152003)the Beijing Municipal Commission of Education of China(Grant Nos.PXM2017 014204 500034 and PXM2016 014204 500018)
文摘Interference filter-stabilized external cavity diode lasers （ECDLs） have properties of simple configurations, high sta- bilities, and narrow linewidths. However, the interference filter used in common ECDL designs requires an ultra-narrow bandwidth （about 0.3 nm） to achieve mode selection, that is considerably expensive and not yet available for a wide range of wavelengths. In this paper, a robust ECDL using an available broad bandwidth （about 4 nm） interference filter as the wavelength discriminator is constructed and tested. The ECDL demonstrated a narrow Lorentzian fitted linewidth of 95 kHz and a spectral purity of 2.9 MHz. The long-term frequency stability of the ECDL reaches 5.59 x 10 12.
基金Jiangsu Province Key R&D Program(Industry Prospect and Common Key Technologies)(No.BE2014083)Jiangxi Natural Science Foundation Project(No.2019ACBL20054)。
文摘Narrow linewidth light source is a prerequisite for high-performance coherent optical communication and sensing.Waveguide-based external cavity narrow linewidth semiconductor lasers(WEC-NLSLs)have become a competitive and attractive candidate for many coherent applications due to their small size,volume,low energy consumption,low cost and the ability to integrate with other optical components.In this paper,we present an overview of WEC-NLSLs from their required technologies to the state-of-the-art progress.Moreover,we highlight the common problems occurring to current WEC-NLSLs and show the possible approaches to resolving the issues.Finally,we present the possible development directions for the next phase and hope this review will be beneficial to the advancements of WEC-NLSLs.
基金supported by the Research Project of Aerospace Information Research Institute,Chinese Academy of Sciences (Grant Nos.E1Z1D101 and E2Z2D101)the Project of Chinese Academy of Sciences (Grant No.E33310030D)the Guangzhou Basic and Applied Basic Research Foundation (Grant Nos.2023A04J0336 and 2023A04J0021).
文摘A 60-mW solid-state deep ultraviolet(DUV)laser at 193 nm with narrow linewidth is obtained with two stages of sum frequency generation in LBO crystals.The pump lasers,at 258 and 1553 nm,are derived from a homemade Yb-hybrid laser employing fourth-harmonic generation and Er-doped fiber laser,respectively.The Yb-hybrid laser,finally,is power scaling by a 2 mm×2 mm×30 mm Yb:YAG bulk crystal.Accompanied by the generated 220-mW DUV laser at 221 nm,the 193-nm laser delivers an average power of 60 mW with a pulse duration of 4.6 ns,a repetition rate of 6 kHz,and a linewidth of∼640 MHz.To the best of our knowledge,this is the highest power of 193-and 221-nm laser generated by an LBO crystal ever reported as well as the narrowest linewidth of 193-nm laser by it.Remarkably,the conversion efficiency reaches 27%for 221 to 193 nm and 3%for 258 to 193 nm,which are the highest efficiency values reported to date.We demonstrate the huge potential of LBO crystals for producing hundreds of milliwatt or even watt level 193-nm laser,which also paves a brand-new way to generate other DUV laser wavelengths.
基金supported by the Natural Science Foundation of Hebei Province(No.F2016201023)the Technology Foundation for Selected Overseas Chinese Scholar of Ministry of Human Resources and Social Security of China(No.CG2015003006)the Advanced Talents Program of Hebei Educational Committee(No.GCC2014020)
文摘We propose and demonstrate a novel single-longitudinal-mode(SLM) erbium-doped fiber laser(EDFL) capable of operating at fixed-wavelength lasing mode with a tunable range more than 54 nm, an ultra-narrow linewidth of 473 Hz and an ultra-high optical signal-to-noise ratio(OSNR) more than 72 dB, or operating at wavelength-swept mode with tunable sweep rate of 10—200 Hz and a sweep range more than 50 nm. The excellent features mainly benefit from a triple-ring subring cavity constructed by three optical couplers nested one another and a fiber Fabry-Pérot tunable filter which can be driven by a constant voltage or a periodic sweep voltage for fixed or wavelength-swept operation, respectively. The proposed EDFL has potential applications in high-resolution spectroscopy and fiber optic sensing.
基金National Natural Science Foundation of China(62205317).
文摘Stimulated Brillouin scattering(SBS)-induced mode distortion(MD)in high power narrow linewidth fiber amplifiers has been implemented,and the origin has been investigated from the aspect of the evolution of the optical spectrum,spatial beam profiles,and temporal-frequency domain characteristics.
基金supported by the National Key Research and Development Program of China under Contracts No.2024YFA1209202the National Natural Science Foundation of China(Grant No.U22A6004 and No.62301294)the Frontier Science Center for Quantum Information.
文摘Lasers with the gain medium of gas,liquid,semiconductor,and solid could generate coherent light with rather narrow spectral linewidth,which play an important role in the fields of communication,measurement,sensing,and so on.Although free electron lasers have been realized with their unique advantages,they face challenges in narrowing the spectral linewidth,owing to electron energy fluctuation,Coulomb effect,and other mechanism.Here we demonstrate the superradiant Smith-Purcell radiation(S-SPR)in terahertz frequency band with ultra-narrow and continuously tunable linewidth in a compact device.By proposing a new effect of pump-induced stimulated S-SPR(PIS-SPR),the spectral linewidth could be reduced to 0.3 kHz@291.7 GHz,which is about two–six orders of magnitude narrower compared with those obtained by accelerators and other electron devices.Meanwhile,the wide range of continuously tunable spectral linewidth spanning 0.3–900 kHz is observed for the first time.This work provides a way to greatly narrow the spectral linewidth of free electron radiation and to achieve high-order harmonic of S-SPR in a compact device,and offers a platform to study the interaction between free electron bunches and different micro-&nano-structures.
基金the Agence Nationale de la Recherche(grant ANR-12-EMMA-0040‘‘Vecspresso’’project)the Region Ile de France(DIMNano’K)the LABEX SEAM for funding this work.
文摘Optically pumped lasers based on solution-processed thin-film gain media have recently emerged as low-cost,broadly tunable,and versatile active photonics components that can fit any substrate and are useful for,e.g.,chemo-or biosensing or visible spectroscopy.Although single-mode operation has been demonstrated in various resonator architectures with a large variety of gain media-including dye-doped polymers,organic semiconductors,and,more recently,hybrid perovskites-the reported linewidths are typically on the order of a fraction of a nanometer or broader,i.e.,the coherence lengths are no longer than a few millimeters,which does not enable high-resolution spectroscopy or coherent sensing.The linewidth is fundamentally constrained by the short photon cavity lifetime in the standard resonator geometries.We demonstrate here a novel structure for an organic thin-film solid-state laser that is based on a vertical external cavity,wherein a holographic volume Bragg grating ensures both spectral selection and output coupling in an otherwise very compact(,cm3)design.Under short-pulse(0.4 ns)pumping,Fourier-transform-limited laser pulses are obtained,with a full width at half-maximum linewidth of 900 MHz(1.25 pm).Using 20-ns-long pump pulses,the linewidth can be further reduced to 200 MHz(0.26 pm),which is four times above the Fourier limit and corresponds to an unprecedented coherence length of 1m.The concept is potentially transferrable to any type of thin-film laser and can be ultimately made tunable;it also represents a very compact alternative to bulky grating systems in dye lasers.
基金supported by the National Natural Science Foundation of China(Grant Nos.61322505 and 61705264)the Foundation for the Author of National Excellent Doctoral Dissertation of China(Grant No.201329)
文摘Yb-doped fiber laser(YDFL) is a promising kind of laser source due to high efficiency, excellent beam quality, robust configuration, diverse applications and so on. The progress of large-mode-area double cladding active fiber and high power laser diodes have been continuously promoting the power scaling of the YDFLs. However, the further power scaling is blocked by some physic issues including nonlinear effect, thermal-induced mode instability(MI), optical damage and so forth. So, newlydesigned fibers with special structures are invented to address or relieve these limitations. The tapered fiber, which has changed mode area along its longitudinal direction, has been demonstrated to benefit suppressing the nonlinear effect, especially the stimulated Brillouin scattering(SBS) effect. In this paper, we will review the previous work done to explore the advantages of the tapered fiber for high power output, and then for the first time to our knowledge, demonstrate an all-fiberized high power narrow linewidth fiber laser based on a homemade tapered Yb-doped fiber(T-YDF). As a result, an output power of 260 W with a narrow linewidth of ~2 GHz is obtained, with SBS effectively suppressed owing to gradually increased mode area of the T-YDF as well as continuously changed Brillouin frequency shift dependent on the core diameter. Further power scaling is limited by MI, and the features of MI are studied in detail. It is pointed out that, the MI seems the primary and durative limitation factor of the tapered fiber amplifier for high power narrow linewidth output due to the gradually increased effective numerical aperture(NA) and the excitation of the high-order modes, even although it has the advantage to reduce other nonlinear effects. At last,worthwhile discussion about the optimization of the T-YDF and the whole fiber laser system for both SBS and MI suppression is conducted based on the previous and our results. It is concluded that the small diameter at the small-diameter end and low optical NA are preferred in the design of a T-YDF to ensure good beam quality and improve the MI threshold. The good splicing quality and proper coiling or bend state are also necessary.
基金supported by the National Natural Science Foundation of China(No.11274385)
文摘We report here a high-power, wavelength tunable and narrow linewidth 1.5 μm all-fiber laser amplifier based on a tunable diode laser and Er-Yb co-doped fibers. The laser wavelength can be precisely tuned from 1535 nm to 1580 nm, which covers many absorption lines of mid-infrared laser gases, such as C2 H2, HCN, CO, and HI. The maximum laser power is >11 W, and the linewidth is about 200–300 MHz, which is close to the absorption linewidth of the above-mentioned gases. This work provides a suitable pump source for high-power wavelength tunable mid-infrared fiber gas lasers based on low-loss hollow-core fibers.
基金This work is supported by the International Science and Technology Cooperation Program of China （2012DFA10730） and Natural Science Foundation of China （61307101 and 61205083）.
文摘A narrow linewidth laser configuration based on distributed feedback fiber lasers （DFB-FL） with eight wavelengths in the international telecommunication union （ITU） grid is presented and realized. In this laser configuration, eight phase-shifted gratings in series are bidirectionally pumped by two 980-nm laser diodes （LDs）. The final laser output with over 10-mW power for each wavelength can be obtained, and the maximum power difference within eight wavelengths is 1.2 dB. The laser configuration with multiple wavelengths and uniform power outputs can be very useful in large scaled optical fiber hydrophone fields.
基金supported by the National Natural Science Foundation of China(NSFC)(No.52075131)。
文摘A whispering gallery mode resonator(WGMR)filter can narrow laser linewidth while significantly changing the output power characteristics of fiber laser system.It is found that traditional laser output power model is invalid.We report a correction model of a narrow linewidth fiber laser filtered with a WGMR to analyze its power.We believe that the loss of the laser system and the threshold gain increase caused by the WGMR filter lead to the predominate amplified spontaneous emission during the original laser period.According to that,we assume the correction coefficient is an exponential decay related to the Er-doped fiber length in the large loss situation,and we verify it experimentally.As a result,the correction model is valid for WGMR-filtered fiber laser.
基金Project supported by the National Basic Research Program of China (Grant No. 2011CB921603)the National Natural Science Foundation of China (Grant Nos. 11074097,10904048,10974071,and 11004080)
文摘We investigate the resonance fluorescence spectrum of an atomic three-level ladder system driven by two laser fields. We show that such a system emulates to a large degree a V-type atom with parallel dipole moments-the latter being a system that exhibits spontaneously generated coherence and can display ultrasharp spectral lines. We find a suitable energy scheme in a SSRb atom and experimentally observe the narrowing of the central peak in a rubidium atomic beam. The corresponding spectrum can convindngiy demonstrate the existence of spontaneously generated coherence.
基金supported by the National Natural Science Foundation of China(Grants Nos.11204080,11274112,91321101,and 61275215)the Fundamental Research Fund for the Central Universities of China(Grants No.WM1313003)
文摘We present a quantum-theoretical treatment of cavity linewidth narrowing with intracavity electromagnetically in- duced transparency （EIT）. By means of intracavity EIT, the photons in the cavity are in the form of cavity polaritons： bright-state polariton and dark-state polariton. Strong coupling of the bright-state polariton to the excited state induces an effect known as vacuum Rabi splitting, whereas the dark-state polariton decoupled from the excited state induces a narrow cavity transmission window. Our analysis would provide a quantum theory of linewidth narrowing with a quantum field pulse.
文摘The output characteristics of a narrow linewidth, no-gain competition, dual-wavelength solid-state laser using an intra-cavity pumped method are reported. This system consists of an intra-cavity pumped Nd:YVO4 laser emitting at 1064 nm, using a 912 nm Nd:GdVO4 laser. A Fabry-Perot etalon is used to compress the linewidth that located at the common cavity of 912 nm and 1064 nm laser. Theoretical analysis and experimental verification were carried out. When the pump power is 32.8 W, the output of 912 nm and 1064 nm theoretical value is 0.036 W and 0.046 W, and the experimental value is 0.017 W and 0.016 W, respectively. The change trend of the theoretical simulated output power value was the same as the actual measured value in the experiment. In addition to this, the experimental measurement shows when the etalon with an angle of 15?, corresponding minimum linewidths were 0.284 nm and 0.627 nm, respectively.
基金Project supported by the National Natural Science Foundation of China (Grant No 60490280)the State Key Development for Basic Research Program of China (Grant Nos 2006CB806005 and 2006CB921104)+2 种基金the Science and Technology Commission of Shanghai Municipality, China (Grant Nos 06JC14026 and 07JC14019)Shanghai Pujiang Talent Program, China (Grant No 07PJ14038)the Program for Changjiang Scholars and Innovative Research Teams, China
文摘Two Nd：YAG lasers operating at 1064 nm are separately servo-locked to two vertically mounted ultra-stable cavities. The optical heterodyne beat between two cavity-stabilized lasers shows that the linewidth of each laser reaches 2 Hz and the average frequency drift reduces to less than 1 Hz/s.
基金supported by the Natural Science Foundation of Jilin Province(No.YDZJ202401371ZYTS)the National Natural Science Foundation of China(Nos.62275031,11974060,and 12374397)the Natural Science Foundation of Chongqing Municipality(No.CSTB2022NSCQ-MSX1027)。
文摘This study demonstrates a mid-infrared narrow-linewidth tandem optical parametric oscillator(TOPO)based on dual Mg O:PPLN crystals.A secondary-pumping technique with a periodically poled MgO:PPLN crystal is employed to achieve threewavelength mid-infrared laser outputs at 2.70,3.45,and 4.25μm.A 1064 nm ytterbium-doped fiber laser is employed as the pump source,with a single laser output sequentially pumping two MgO:PPLN crystals which have period lengths of 30.44 and31.89μm,respectively.The synchronous three-wavelength mid-infrared laser output is achieved through two optical parametric oscillation(OPO)processes and one TOPO process.The processes are as follows:1.06μm→1.53μm+3.45μm;1.06μm→1.75μm+2.70μm;1.53μm→2.40μm+4.25μm.The linewidth of the signal light is compressed using a1 mm thick Fabry-Perot(F-P)etalon,reducing the linewidths of 2.70,3.45,and 4.25μm from 3.03,7.83,and 1.20 nm to0.32,0.60,and 0.55 nm,respectively.The associated output powers are 0.681,1.342,and 0.098 W.
基金National Key Research and Development Program of China(2023YFB4604600)National Natural Science Foundation of China(12274133,12334014,12192251,12134001,12474378,12404379)+1 种基金Innovation Program for Quantum Science and Technology(2021ZD0301403)Fundamental Research Funds for the Central Universities,Engineering Research Center for Nanophotonics&Advanced Instrument,Ministry of Education,East China Normal University(2023nmc005)。
文摘Ytterbium ion(Yb^(3+))-doped lasers are widely used in precision machining and precision measurement fields because of their high efficiency and high power,which are primarily based on solid-state lasers and fiber lasers.Here,we demonstrate an on-chip Yb^(3+)-doped thin-film lithium niobate(Yb:TFLN)Fabry-Perot microcavity laser.We achieve single-frequency laser operation at 1030 and 1060 nm with a side-mode suppression ratio above 30 dB,an emission linewidth below 40 pm,and an output power up to 1.5 mW at 1060 nm and 0.3 mW at 1030 nm.In addition,using the electro-optic effect of lithium niobate,we achieve a laser tuning efficiency of 4 pm/V.This work opens the path to on-chip high-power and mode-locked ultrafast laser output.
基金supported by the National Natural Science Foundation of China(Grant Nos.62275031 and U24A2045)the Natural Science Foundation of Jilin Province(Grant No.20240302023GX)。
文摘This paper introduces a high single-pulse energy,narrow-linewidth mid-infrared self-optical parametric oscillator(midIR SOPO)with a cavity length of 120 mm and a Nd:Mg O:PPLN crystal.To achieve high single-pulse energy and high peak power in mid-IR light sources,a LiNbO3 electro-optic Q-switch(EOQ)is introduced for the first time in a midIR SOPO.A narrow-linewidth EOQ-SOPO rate equation is formulated,and experiments are conducted using a single Fabry–Pérot etalon.At a 500μs pump pulse width,a 4.71 m J single-pulse idler light at 3838.2 nm is achieved,with a linewidth of 0.412 nm,single-pulse width of 4.78 ns and peak power of 985 k W.At 200μs,the idler light at 3845.2 nm exhibits a minimum linewidth of 0.212 nm.
