摘要 :
After a brief examination of known insulating laser crystals and the stimulated emission channels of their generating activator ions, this article reviews recent advances in the development of novel lasing crystals and ceramics, a...
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After a brief examination of known insulating laser crystals and the stimulated emission channels of their generating activator ions, this article reviews recent advances in the development of novel lasing crystals and ceramics, as well as inorganic and organic nonlinear-laser crystals for χ(3) and cascaded χ(3) χ(2) frequency converters. Several new modern attractive technologies in the physics and techniques of crystalline lasers are also discussed.
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We report here a wavelength widely step-tunable nanosecond 4 μm fiber laser based on HBr-filled hollow-core fibers (HCFs), which is pumped by an acousto-optic modulated narrow linewidth 2 μm thulium-doped fiber amplifier (TDFA) ...
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We report here a wavelength widely step-tunable nanosecond 4 μm fiber laser based on HBr-filled hollow-core fibers (HCFs), which is pumped by an acousto-optic modulated narrow linewidth 2 μm thulium-doped fiber amplifier (TDFA) seeded by several thermally tunable diode lasers. The modulated pump pulses excite the first overtone transition of the HBr molecules in HCFs with single-pass configuration, resulting in a number of mid-infrared laser emissions containing both P and R branch fundamental transition lines from 3.87 μm to 4.5 μm. To the best of our knowledge, this is the first tunable pulsed mid-infrared fiber laser beyond 3.8 μm, and it is also the largest tuning range achieved to date for any pulsed fiber laser not by nonlinear effects. The maximum average power of 550 mW associated with a single pulse energy of 0.37 μJ (pulse duration 20 ns, pulse repetition rate 1.5 MHz) is achieved at 4.17 μm, and the laser slope efficiency is about 15.6%. The mid-infrared laser shows a good fundamental mode with a measured beam quality factor M 2 of about 1.15. The time and frequency domain characteristics are also experimentally investigated in detail. The versatility of such gas-filled HCF laser offers much flexibility in selected molecule gain media and HCF species for power scaling and wavelength extending of pulsed mid-infrared fiber lasers.
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For decades, researchers have been interested in developing efficient rare-earth-doped laser sources using dual-wavelength pumping. However, dual-wavelength pumping of rare-earth-doped lasers and amplifiers are currently restricte...
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For decades, researchers have been interested in developing efficient rare-earth-doped laser sources using dual-wavelength pumping. However, dual-wavelength pumping of rare-earth-doped lasers and amplifiers are currently restricted to pump wavelengths longer than the visible. Extending the use of dual-wavelength pumping for directly diode-pumped rare-earth-doped lasers is of great importance for both academic and practical purposes. We have developed the first blue dual-wavelength pumping of Holmium-doped ZrF
4
-BaF
2
-LaF
3
-AlF
3
-NaF (Ho:ZBLAN) fiber lasers operating at 75X nm. A dual-wavelength pumping method was proposed by pumping two separate wavelengths of 449 and 442 nm into a Ho:ZBLAN fiber to populate the upper laser state
$^{5}{\mathrm{F}}_{4} + ^{5}{\mathrm{S}}_{2}$
and depopulate the lower laser state
5
I
7
, respectively. The influence of the 449 and/or 442 nm pumping schemes on the efficiency and threshold of the 75X nm laser was studied by varying the active fiber length. For dual-wavelength pumping with blue laser diodes, a shorter fiber and a lower 449 nm pump power are favoured. Our approach expands the applicability of dual-wavelength pumping to visible laser systems with energy-level structures consisting of long-lived lower-level bottlenecks.
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摘要 :
In part I of this paper, and to set the foundation for this part II, we derived the resonator equations describing the normalized intensities, output power, gain, and extraction efficiency for a standard resonator incorporating tw...
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In part I of this paper, and to set the foundation for this part II, we derived the resonator equations describing the normalized intensities, output power, gain, and extraction efficiency for a standard resonator incorporating two dielectric mirrors and a gain element. We then generalized the results to include an absorbing region representing a second laser crystal characterized by a small-signal transmission T_0. Explicit expressions were found for the output power extracted into absorption by the second laser crystal and the extraction efficiency, and the limits to each were discussed. It was shown that efficient absorption by a thin or dilute second laser crystal can be realized in resonators in which the mirror reflectivities were high and in which the single-pass absorption was low, due to the finite photon lifetime and multi-passing of the absorbing laser element. In this paper, we apply the model derived in part I to thin or dilute laser materials, concentrating on a Yb, Er:glass intracavity pumped by a 946 nm Nd:YAG laser, a Yb, Er:glass laser-pumped intracavity by a 977 nm diode laser, and an Er:YAG laser-pumped intracavity to a 1530 nm diode laser. It is shown that efficient absorption can be obtained in all cases examined.
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1.3- mu m and 1.5- mu m distributed-feedback semiconductor lasers have been frequency stabilized to sub-Doppler resonances of the 5P/sub 1/2/ to 6S/sub 1/2/ and the 5P/sub 3/2/ to 4D/sub 3/2,5/2/ transitions of /sup 85,87/Rb atoms...
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1.3- mu m and 1.5- mu m distributed-feedback semiconductor lasers have been frequency stabilized to sub-Doppler resonances of the 5P/sub 1/2/ to 6S/sub 1/2/ and the 5P/sub 3/2/ to 4D/sub 3/2,5/2/ transitions of /sup 85,87/Rb atoms, respectively. Using these stabilized lasers, the absolute wavenumbers of the transitions have been measured interferometrically with an accuracy of 2*10/sup -7/.
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Stimulated Raman scattering (SRS) enabled by the emerging gas-filled low-loss anti-resonant hollow-core fiber (ARHCF) technology opens up a competitive way towards the development of novel lasers in the molecular fingerprint regio...
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Stimulated Raman scattering (SRS) enabled by the emerging gas-filled low-loss anti-resonant hollow-core fiber (ARHCF) technology opens up a competitive way towards the development of novel lasers in the molecular fingerprint region. In this article, the characteristics of noise and long-term stability of near- and mid-infrared (near-IR and mid-IR) gas-filled fiber Raman lasers have been investigated for the first time. The results reveal that an increase in Raman pulse energy is associated with a decrease in noise, and that the relative pulse peak intensity noise (RIN) is always lower than the relative pulse energy noise (REN). We also demonstrate that long-term drift of the pulse energy and peak power are directly linked with the high amount of heat release during the Raman Stokes generation. The demonstrated noise and long-term stability performance provide necessary references for potential spectroscopic applications as well as further improvements of the emerging IR gas-filled ARHCF Raman laser technology.
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Under the influence of the beam laser, heat is controlled by a material that changes the properties under the thermocycle. The heat equation, which hasthe temperature determination solution according to the space-time distribution...
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Under the influence of the beam laser, heat is controlled by a material that changes the properties under the thermocycle. The heat equation, which hasthe temperature determination solution according to the space-time distribution, describes the laser interaction with the material. The important parameters used in the experimental calculation are laser duration, thermal temperature, melting and vaporization temperature of a metallic sample. With the help of these measurements the penetration depth of the thermal front and the molten depth layer zm is determined for lamellar circular lasers with CO2, Nd: YAG, fiber.
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Versatile controllable high-order transverse laser modes have been generated in a decentered Gaussian beam (DGB) pumped Cr4+:YAG passively Q-switched (PQS) Nd:YAG microchip laser. The DGB has been formed by offsetting collimating ...
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Versatile controllable high-order transverse laser modes have been generated in a decentered Gaussian beam (DGB) pumped Cr4+:YAG passively Q-switched (PQS) Nd:YAG microchip laser. The DGB has been formed by offsetting collimating lens away from the propagation direction of the pump light. Effects of the collimating lens offset distance on the beam profile and tilting angle of the DGB have been investigated experimentally and theoretically. A highly efficient and high repetition rate Laguerre–Gaussian (LG) mode PQS microchip laser is achieved when the ordinary Gaussian beam is used as the pump source. The Ince–Gaussian (IG) mode and Hermite–Gaussian (HG) mode lasers are obtained when the DGB is applied as the pump source. The IG mode laser is changed to an HG mode laser by increasing the offset distance of the collimating lens. Optical efficiencies above 41% respective to the absorbed pump power have been obtained in the DGB pumped LG and IG mode PQS Nd:YAG microchip laser. The nanosecond pulse width and peak power of over 4 kW has been achieved in DGB pumped PQS Nd:YAG microchip lasers for various high-order transverse modes. Our works on the DGB pumped PQS microchip laser for high-order transverse modes provide an effective and simple method for designing highly efficient, controllable LG, IG, and HG mode solid-state lasers.
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We present a novel design for a quasi-three-level laser. The design uses a slab laser configuration with the pump light incident from the slab edge. This allows a lower threshold and better power scaling than a conventional face-p...
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We present a novel design for a quasi-three-level laser. The design uses a slab laser configuration with the pump light incident from the slab edge. This allows a lower threshold and better power scaling than a conventional face-pumped slab. We present an analytic description of pumping optimization, thermal distortion, and power scaling. Several point designs illustrating power scaling are also described.
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