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Ultra-low-intensity-noise single-frequency fiber-based laser at 780 nm
摘要： With the rapid development of precision measurements relying on atom absorption such as atomic inertial sensors and optical magnetometry, advanced lasers are urgently required especially ultralow-noise lasers corresponding to the atom absorption line. For the D2 line of rubidium atoms, an ultralow-intensity-noise 780 nm single-frequency fiber-based laser with an output power of 340 mW is demonstrated. By eliminating polarization sensitivity in the noise suppression process based on the gain saturation of a semiconductor optical amplifier, a relative intensity noise of ?151 dB Hz?1 in the frequency range from 0.1 to 50 MHz is achieved, which approaches the shot noise limit.
关键词： ultralow-intensity-noise,shot noise limit,fiber-based laser,single-frequency,780 nm
更新于2025-09-16 10:30:52
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Novel single-frequency Nd:YAG ring laser by reducing the depolarization loss
摘要： A principle study on reducing the depolarization loss in a single-frequency Nd:YAG ring laser by a novel ring resonator configuration is reported. In the resonator, one cavity mirror with 99.5% reflectivity at 1064 nm for 45-degree incident s-polarized light and about 75% transmissivity for 45-degree incident p-polarized light was employed. Besides, the transmissivity for the 45-degree incident p-polarized and s-polarized light for the output-couple mirror were 32% and 3.5%, respectively. The cavity mirror and the output-couple mirror were utilized as the polarizer to enforce the s-polarized beam unidirectionally operating in the resonator. 2.1 W single-frequency output at 1064 nm with elliptical polarization was obtained from this ring resonator. Compare with the existent Nd:YAG ring resonator, this novel resonator has a potential advantage in reducing depolarization loss and increasing the efficiency.
关键词： Nd:YAG,Depolarization loss,Ring resonator,Single-frequency
更新于2025-09-12 10:27:22
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2?kHz single-frequency, injection-seeded Q-switched laser with a ‘double-reflection’ architecture
摘要： A high-repetition-rate single-frequency injection-seeded Q-switched Er:YAG laser with a ‘double reflection’ architecture is reported. Single-frequency laser pulses at a pulse repetition frequency (PRF) of 2 kHz are obtained by using ‘ramp-fire’ injection-seeding technique. The half-width of the pulse spectrum is measured to be 2.05 MHz by using the heterodyne beating technique. The novel ‘double-reflection’ architecture is employed in order to achieve a stable high-repetition-rate single-frequency operation. As far as we know, 2 kHz is the highest PRF achieved from a single-frequency, injection-seeded Q-switched Er:YAG laser that can be used in a wind Lidar system.
关键词： single-frequency lasers,eye-safe lasers,solid-state lasers,Q-switching,diode-pumped lasers,injection-seeding,Er:YAG lasers
更新于2025-09-12 10:27:22
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Comparison of Nd:YVO <sub/>4</sub> -Based Monolithic Microchip Laser Resonators for Single-Frequency Stable, CW Diode-Pumped Laser Sources
摘要： Single-frequency stable, narrow linewidth diode-pumped solid state (DPSS) lasers are commonly used in many applications and science areas, like high-resolution spectroscopy, optical metrology, gravity-wave detection, fundamental physics and others. Many of them require optical amplification of the DPSS seed laser to obtain higher output power while maintaining the excellent optical properties of the laser beam (e.g. Coherent Power Summation for military applications). In Ref.[2] the miniature, single-frequency stable DPSS laser operating at 1064 nm and patented structure of the monolithic microchip resonator Nd:YVO4/YVO4/YVO4 were described (Fig.1a). However, from commercial point of view the DPSS seed laser needs to be inexpensive, mechanically and optically stable for wide temperature range, easy to assemble and service. Here, the comparison of the 0.3 mm long a-cut Nd:YVO4 crystal resonator (Fig. 1b) with dielectric mirrors directly deposited onto the outer crystal surfaces (short resonator-SR) and described in Ref.[3] the 8.5mm long microchip resonator Nd:YVO4/YVO4/YVO4 (long resonator-LR) is presented for the first time. Both resonators were examined in the same DPSS laser module, providing the same conditions for their operation and they were pumped through a 3.5 mm long GRIN-lens collimator (Casix) by a linearly polarized 1W multimode 808 nm laser diode (QA-808-1000-030, Axcel Photonics). In comparison to the LR, the SR configuration provides only 27% less power conversion efficiency (at only 0.3mm resonator/gain crystal thickness) due to back reflection from HR@808nm coating of the pump beam. However, for the 808 nm pump power lower than 250 mW, the SR ensures slightly more output power than LR configuration due to 10-times lower power threshold (Fig. 1c). The pure single longitudinal mode operation was obtained for both configurations (Fig. 1e), nonetheless the SR provides almost 9-times wider temperature range (14-32°C @ 550mW of pump power) where laser resonator works in single mode (SM) regime (Fig. 1d), than the LR chip (21.2-23.2 °C @ 550mW of pump power). Additionally, the SR configuration does not need a crystals bonding process and it is around 25% cheaper (excluding bonding costs) compared to the LR. Whereas, the output beam divergence becomes around 4-times higher for the SR and it is more sensitive to angular aligning of the pump beam causing that transverse mode distribution can occur. Presented results and comparison were carried out within a commercial TANGO project “Development, optimization and integration of the single frequency seed laser operating at 1064 nm with medium power fiber amplifier”, (TANGO1/266345/NCBR/2015) financed by National Centre for Research and Development (NCBiR), Poland and statutory funds of the Faculty of Electronics (0401/0030/18).
关键词： single-frequency,optical amplification,diode-pumped solid state lasers,monolithic microchip laser,Nd:YVO4
更新于2025-09-12 10:27:22
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Tailoring Single-Frequency VECSELs for Quantum Technology Applications
摘要： Many quantum technology applications, such as quantum information processing, precision metrology, and atomic clocks, rely on lasers at many different wavelengths with demanding characteristics in terms of power, linewidth, beam quality, and intensity noise. These lasers are typically used to detect or change the quantum states of neutral atoms and ions. Besides the need for precisely defined features fitting a specific atom/ion system, there is an increasing need to make such lasers more affordable, as well as easier to use and tailor, in order to ensure faster transit from lab to real applications. Vertical-External-Cavity Surface-Emitting Lasers (VECSELs, aka. OPSLs or SDLs) are optically pumped semiconductor lasers that combine the benefits of semiconductor quantum well -lasers; the wavelength versatility and the wide pump absorption bandwidth, with the benefits of diode-pumped solid-state lasers; the high output power and excellent beam quality. The external cavity geometry of VECSELs enables the insertion of intracavity wavelength selective elements for tunable single-frequency operation, and the insertion of nonlinear crystals for efficient intracavity frequency conversion. These features make VECSELs very promising candidates to address the needs of quantum technology and other high impact applications. We present compact turnkey single-frequency VECSELs tailored for quantum technology applications, for generation and manipulation of trapped ions for quantum computing. Our previous demonstration was focused on VECSEL-based systems at 279.6 nm for Doppler cooling and at 285.3 nm for photoionization of magnesium ions. Here, we focus on wavelength extension and tailoring the single-frequency operation for use with several other promising ions, such as beryllium at 313 nm and 235 nm. We present very recent results of Watt-level single-frequency emission at challenging 1252 nm and 940 nm wavelengths, which are prerequisites for high power emission at 313 nm and 235 nm, as well as recent developments on the laser platform. We believe that VECSELs can potentially replace many of the laser systems currently in use and enable new quantum technology applications.
关键词： single-frequency lasers,VECSELs,quantum computing,quantum technology,trapped ions
更新于2025-09-12 10:27:22
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Up-Scaling the Power of Pulsed Single Frequency Fibre Amplifiers for Coherent LIDAR Applications
摘要： In optical sensing applications, the laser sources are strongly constrained by the sensing system requirements. In the case of coherent LIDARs, that measure wind speed thanks to the Doppler shift (by means of a coherent detection), highly coherent high power pulsed lasers with good output beam quality are necessary to guarantee a proper measurement over long distances. The pulsed emission ensures the spatial resolution along the line of sight whereas the high coherence accounts for the wind speed resolution (measured in the frequency domain). Thus, the challenge when designing laser sources for such instruments resides in the difficulty of improving the output power while not altering the other characteristics. Fibre lasers and amplifiers have proven their interest in high power laser systems thanks to their compactness and their stability against temperature and mechanical fluctuations. The increase of emitted optical power is currently limited by nonlinear effects due to the intrinsically high confinement of the optical field in fibres. Among all the nonlinear effects, the Stimulated Brillouin Scattering (SBS) predominates in the case of single frequency or narrow spectrum optical fields. In order to increase the power of single frequency fibre lasers, many developments have been done in the past decades to mitigate SBS. We can class the different SBS mitigation techniques in two categories depending on whether they act on the optical field properties or on the optical fibre itself. All the techniques belonging to the first category are based on an active control of the phase or the frequency of the incident optical wave, in order to spread the incident energy in the spectral domain. In the second category, we can maximize the core radius of the fibre, minimize the fibre length, apply temperature gradients, dopant concentrations gradients or strain gradients to broaden the SBS spectrum in a controlled manner and thus lower its effective gain. We review here the different techniques we use to mitigate the SBS in pulsed single frequency fibre amplifiers and discuss their conceptual and technical limitations. Among all the existing mitigation techniques, we present here different realizations of fibre amplifiers designed for coherent LIDAR systems, based on strain gradients [1] and specifically designed highly doped and large core active fibres [2]. Figure 1 presents the typical achievements obtained with our patented tensile and compressive strain gradients techniques when applied to active fibers. We are able to increase the output power by a factor 2 to 3 while keeping a high beam quality on a highly coherent laser emission. We emphasize the robustness of such developments thanks to the absence of active devices that make them suitable for embedded sensing applications.
关键词： coherent LIDAR,high power pulsed lasers,Stimulated Brillouin Scattering,SBS mitigation,single frequency fibre amplifiers
更新于2025-09-11 14:15:04
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - All-Fiber 100-ns Single-Frequency 0.5mJ Anisotropic MOPA with Double Clad Tapered Yb-Doped Gain Fiber
摘要： High peak power, single-frequency pulsed fiber MOPA sources with extremely narrow line and nanosecond pulses are in highly demand to date. Such sources are required for various applications, including coherent LIDARs systems, remote sensing, and frequency conversion [1]. Stimulated Brillouin scattering (SBS) arising is a main obstacle to further peak power and pulse energy scaling [2]. There are several strategies for SBS suppression in the fiber MOPA have been described in the literature to date. These include exploiting a longitudinal temperature or mechanical stresses gradient in a gain fiber [3] or by using a birefringent fiber with both eigenstates excited. In [4] Stolen has demonstrated doubling of SBS threshold in birefringent fiber with equally excited fast and slow waves. Tapering of a fiber is significantly increases a SBS threshold [5].Usually, authors have used only one of abovementioned strategies for SBS mitigation. Meanwhile, all these measures might be imposed simultaneously by using a short, active, tapered, end pumped (aiming strong temperature gradient) fiber with large mode field diameter fiber. The experimental set up is shown in Fig.1. In conclusion, we have presented short (1.2m), tapered, birefringent, ytterbium doped, end pumped double clad fiber MOPA system with 40μm mode field diameter for amplification of single-frequency long pulses (100ns) for coherent LIDAR application. We have reached record 0.522mJ pulse energy and demonstrated highest to date 5kW peak power by using anisotropic active tapered double clad fiber as a gain media and exciting both slow and fast polarization waves.
关键词： single-frequency,tapered fiber,SBS suppression,fiber MOPA,coherent LIDAR
更新于2025-09-11 14:15:04
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[IEEE 2018 Asia Communications and Photonics Conference (ACP) - Hangzhou (2018.10.26-2018.10.29)] 2018 Asia Communications and Photonics Conference (ACP) - Yttrium aluminosilicate (YAS) fiber with heavily doped of Nd for single frequency laser
摘要： We demonstrate a single frequency lasers based on the yttrium aluminosilicate (YAS) fiber with heavily doping concentration of Nd3+. This multi-component YAS fiber shows the potential for single frequency lasers.
关键词： YAS glass,single frequency lasers,fiber
更新于2025-09-11 14:15:04
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Direct Generation of a Laguerre-Gaussian-Mode Optical Vortex Beam in a Single-Frequency Nd:YVO4 Unidirectional Ring Laser
摘要： A single-frequency, unidirectional ring laser with a ?rst order Laguerre-Gaussian (LG01) mode output end-pumped by using a ring-shaped pump beam is reported. This approach has been applied to a diode-pumped Nd:YVO4 laser in a traveling wave resonator con?guration yielding 2.1 W and 1.5 W of single-frequency LG01 mode outputs with helical wavefronts of left- and right-handedness, respectively. Moreover, we show that its wavefront helicity can be switched by changing the lasing direction and frequency. The selection mechanism of the wavefront helicity and the prospects of this approach are discussed.
关键词： Diode-pumped solid state lasers,Single-frequency laser,Optical vortices,Laguerre-Gaussian mode
更新于2025-09-11 14:15:04
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Effect of a Low-Frequency Noise Signal on the Supply Circuit of the Millimeter-Band Generator of Single-Frequency and Chaotic Oscillations Designed on an Avalanche Transit-Time Diode
摘要： The effect of a low-frequency noise signal on the supply circuit of a millimeter-band generator of single-frequency and chaotic oscillations designed on an avalanche transit-time diode has been experimentally investigated. Generation of noise oscillations under the action of a low-frequency narrowband (~3 MHz) noise signal on the supply circuit of an avalanche transit-time diode in a single-frequency self-oscillator based on a 7-millimeter-wave avalanche transit-time diode has been obtained for the first time and the possibility of control of the spectral characteristic of a 8-millimeter-band noise generator on an avalanche transit-time diode using such an impact has been demonstrated.
关键词： single-frequency oscillations,avalanche transit-time diode,millimeter-band generator,low-frequency noise signal,chaotic oscillations
更新于2025-09-10 09:29:36