Download or read book Continuous Wave Diode Pumping and Pulsed Operation of Alexandrite Lasers Near 760 Nm and Tm3 YLF Lasers Near 2300 Nm written by İsmail Yorulmaz and published by . This book was released on 2017 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Efficient CW Nd YLF Laser In band Diode pumped at 908 Nm and Its Thermal Lensing written by Zohreh Sedaghati and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Diode-pumped solid-state lasers are highly recommended for a variety of industrial and scientific applications as they can offer high efficiency and excellent beam quality. However, power scaling of these lasers is a challenging task. The main limitation in power scaling of famous neodymium doped lasers such as Nd:YVO4 is the thermal lensing effect. Thermal lensing degrades the output beam quality and in extreme cases can result in crystal fracture. One potential solution to this problem is to reduce the induced heat load inside the gain media by decreasing the quantum defect. This was demonstrated successfully for the Nd:YVO4 laser by pumping the laser at a long wavelength of 914 nm instead of the traditional pumping at 808 nm wavelength. Among the Nd-doped crystals operating in the near infrared range, the crystal of yttrium lithium fluoride (Nd:YLF) is another interesting gain medium as it has the benefits of natural birefringence (can generate naturally polarized laser beam), negative dn/dT (reduces thermal effects) and long upper level lifetime (in favor of Q-switched operation). In this work we used a long wavelength pumping approach and for the first time examined the performance of a continuous-wave Nd:YLF laser at 1047 nm under 908 nm diode pumping. This pumping wavelength reduced the quantum defect by 50% as compared to the conventional 808 nm pumping. The laser produced an output power of 850 mW at 1047 nm with excellent beam quality and 625 mW at 1053 nm. The slope efficiency was ~73.9% and 46% for 1047 and 1053 nm, respectively. Therefore, a considerable power scaling is possible for Nd:YLF crystals owing to the strongly reduced quantum defect and, hence, thermal lensing.

Download or read book Passively Mode locked Picosecond Nd KGW Laser with Low Quantum Defect Diode Pumping written by Md. Zubaer Eibna Halim and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Solid-state lasers are capable of providing versatile output characteristics with greater flexibility compared to other popular laser systems. Lasing action has been achieved in many hundreds of solid-state media, but Nd-ion doped gain media are widely used to reach high power levels with short pulses. In this work, commercially available Nd:KGW crystal served as a gain medium to achieve pulsed operation at 1067 nm. This laser crystal offers large stimulated emission crosssection and gain bandwidth which facilitates generation of high peak power pulses in the picosecond regime. The KGW crystal is monoclinic and biaxial in structure, and anisotropic in its optical and thermal properties. Due to poor thermal conductivity, this crystal can be operated within a limited power range before crystal fracture takes place. To reduce the amount of heat deposited in the gain media, we introduced a new pumping wavelength of 910 nm which reduces the quantum defect by more than 45%. Continuous-wave laser operation was optimized to operate in mode-locked regime. In order to achieve short light pulses from the continuous-wave laser, one of the end mirrors was replaced by a semiconductor saturable absorber mirror (SESAM) to generate 2.4 ps pulses at a repetition rate of 83.8 MHz. An average output power of 87 mW was obtained at lasing wavelength of 1067 nm and the beam was nearly diffraction limited with M^2 1.18. The peak power of the generated pulses was 427 W and energy of each pulse was 1 nJ. Pumping the crystal at longer wavelength (910 nm) reduced the thermal lensing of the crystal by half when compared to conventional pumping at shorter wavelength (808 nm). To the best of our knowledge, this is the first time passive mode-locking of a Nd:KGW laser was explored using the pump wavelength at 910 nm.

Download or read book Continuous wave and Passively Mode locked Alexandrite Lasers Pumped at 532 Nm written by Shirin Ghanbari and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Alexandrite crystal (Cr-ion doped chrysoberyl, Cr3+: BeAl2O4) is an attractive gain medium for producing ultrashort laser pulses. Alexandrite properties are similar to those of the Ti:sapphire crystal, which is the most widely used crystal for creating ultrashort pulses. Therefore, Alexandrite can be a good candidate for development of ultra-short pulse lasers. To date, the generation of femtosecond pulses from an Alexandrite laser has not been reported. The primary aim of this research was to create an ultrashort pulse Alexandrite laser. In the first stage of this research, a continuous- wave Alexandrite laser was designed, built and optimized to provide maximum output power. Also, its laser beam quality and wavelength tuning range using a single plate birefringent filter was measured. In addition, the basic behavior of the laser to determine its thermal lensing was investigated. Furthermore, a dual-wavelength operation using several single plate birefringent filters was demonstrated for the first time. In the second stage of this research, ultrashort pulses of 420 fs and 380 fs duration from a quantum-dot saturable absorber mode-locked Alexandrite laser were obtained for the first time. Finally, a femtosecond Kerr-lens mode-locked Alexandrite laser that produced 170 fs long pulses was created for the first time. These results can lead to the development of efficient ultrafast Alexandrite oscillators and amplifiers that can replace widely used inefficient and costly Ti:sapphire laser systems.

Download or read book Tapered Diode pumped Continuous wave Alexandrite Laser written by Ersen Beyatli and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Tunable CW Er YLF Diode Pumped Laser written by and published by . This book was released on 2003 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: We report a 4-W, 2810-nm, diode-pumped, cw Er:YLF laser, to the best of our knowledge the highest power yet achieved for a cw Er-doped laser operating on the(4)I(11/12) - (4)I(13/2) transition. We tuned the laser on 11-different lines in the 2720-2840-nm region.

Download or read book High Power Continuous Wave Nd KGW Laser with Low Quantum Defect Diode Pumping written by Rubel Chandra Talukder and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: High power diode-pumped solid state (DPSS) lasers are a rapidly growing technology that is attractive for various applications in scientific and industrial fields. DPSS lasers are highly efficient, reliable and durable with superior beam quality when compared to flash-lamp pumped solid state lasers. Double-tungstate crystal of neodymium-doped potassium gadolinium tungstate (Nd:KGW) is one of the most effective active media used in DPSS lasers for generation of continuous wave radiation and ultrashort (i.e. picosecond, 10-12 s) pulses. Unfortunately, the thermal conductivity of KGW host crystals is relatively low (~3 Wm-1K-1). This low thermal conductivity and large quantum defect while pumping with ~808 nm lead to significant thermo-optical distortions. One way to minimize thermo-optical distortions is to reduce the quantum defect. This can be done by pumping at longer wavelengths as compared to conventional 808 nm. In this work we demonstrate what we believe is the first continuous wave Nd:KGW laser with hot band diode pumping at ~910 nm. This pumping wavelength reduced the quantum defect by >46% as compared to the conventional ~808 nm pumping and resulted in significantly lower thermal lensing. The laser produced 2.9 W of average output power at 1067 nm in a diffraction limited beam for an absorbed pump power of 8.3 W. The slope efficiency and optical-to-optical efficiency were found to be 43% and 35%, respectively. Significant reduction of quantum defect offered by this pumping wavelength and availability of suitable high power laser diodes opens an attractive way to further power and efficiency scaling of the Nd:KGW lasers.

Download or read book High Power Operation of the In band Diode pumped Nd GdVO4 Lasers written by Mohammad Nadimi and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The main obstacle in power scaling of the well-known Nd-doped lasers such as Nd:YVO4 is the thermal lensing effect. One of the proposed solutions to effectively alleviate this problem was based on the reduction of heating within the laser crystal. This was extensively investigated with the Nd:YVO4 crystal by pumping the laser at 914 nm instead of the standard pumping at 808 nm wavelength. In context of high power applications, the crystal of Nd:GdVO4 is an interesting alternative to the Nd:YVO4 as it offers the benefits of good spectral features (similar to Nd:YVO4) and much higher thermal conductivity. However, there is only one proof-of-principle work on continuous-wave (CW) Nd:GdVO4 laser using this pumping approach in which an output power of 3.35 W was reported. The full power scaling potential of the Nd:GdVO4 laser crystal to produce high output power has not been demonstrated to date. In this PhD thesis, I addressed this issue and investigated the high power operation of Nd:GdVO4 lasers under a new pumping wavelength of 912 nm. First, the thermal lensing behaviour of a 1063 nm Nd:GdVO4 was studied, both experimentally and by finite element analysis (FEA) method. The thermal lensing strength in Nd:GdVO4 laser under 912 nm pumping was significantly reduced when compared to the Nd:GdVO4 laser with 808 nm pumping or even Nd:YVO4 laser with 914 nm pumping. The next step of this research was focused on high power operation of Nd:GdVO4 lasers where we achieved 19.8 W of output power at 1063 nm. As a side work in the CW regime of operation, the possibility of discrete wavelength tuning and dual-wavelength operation of the Nd:GdVO4 laser were examined by using an intracavity birefringent filter. Discrete wavelength operation at four different wavelengths was demonstrated. Furthermore, for the first time we were able to demonstrate a dual-wavelength operation of the Nd:GdVO4 laser as a 1063 and 1071 nm wavelength pair. The last aspect of this PhD thesis was concentrated on generation of picosecond pulses. We were able to report on the first semiconductor saturable absorber mirror (SESAM) mode-locked (ML) Nd:GdVO4 laser with 912 nm pumping. The laser generated 10.14 W of average output power with the pulse width of 16 ps at the repetition rate of 85.2 MHz. To the best of our knowledge this is the highest average output power ever obtained from any of the SESAM mode-locked Nd-doped solid-state lasers that were pumped around 912 nm.

Download or read book Diode Laser pumped Neodymium Lasers in Pulsed and Continuous Wave Operation written by Bruno Frei and published by . This book was released on 1993 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book New Diode Wavelengths for Pumping Solid state Lasers written by and published by . This book was released on 1995 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: High-power laser-diode arrays have been demonstrated to be viable pump sources for solid-state lasers. The diode bars (fill factor of 0.7) were bonded to silicon microchannel heatsinks for high-average-power operation. Over 12 W of CW output power was achieved from a one cm AlGaInP tensile-strained single-quantum-well laser diode bar. At 690 nm, a compressively-strained single-quantum-well laser-diode array produced 360 W/cm2 per emitting aperture under CW operation, and 2.85 kW of pulsed power from a 3.8 cm2 emitting-aperture array. InGaAs strained single-quantum-well laser diodes emitting at 900 nm produced 2.8 kW pulsed power from a 4.4 cm2 emitting-aperture array.

Download or read book Continuous wave Diode pumped Cr YAG Laser written by and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We describe a diode-pumped Cr[sup 4+]:YAG laser operating at 1.45 [mu]m. The laser outputs xxx mW when pumped by a 2 W single-transverse-mode 980 nm InGaAs diode.

Download or read book Controllable Continuous wave Dual wavelength Operation of In band Diode pumped Nd GdVO4 Nd YVO4 Composite Laser written by Chinedu Onyenekwu and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents a controllable continuous-wave dual-wavelength diode-pumped laser based on a composite Nd:GdVO4/Nd:YVO4 crystal. Controllability for the pair of spectral output was achieved by changing the operating temperature of the fiber-coupled laser diode pump using a digital temperature controller. The resulting temperature-dictated pumping wavelength provided a precise and turnkey means of intensity control for the two emitted spectral lines as either line showed strong and proportionate intensity change in response to the wavelength of excitation by the pump. The intensity ratio for the pair was in favor of the GdVO4 emission at 1063 nm while pumping at about 912 nm while the YVO4 emission was relatively lower and vice versa while pumping at 914 nm. For power scalability, a low-quantum defect (QD) approach was adopted using in-band pumping. This was specifically performed around the 910 - 914 nm wavelength range considering and corresponding to the longer Nd:GdVO4/Nd:YVO4 absorption bands. Using this efficiency-increasing initiative, the laser produced a maximum output power of 4.48 W with 11.55 W of absorbed power, corresponding to a slope and optical-to-optical efficiency of 43.8 % and 38.8 % respectively. These parameters are notably the highest ever reported compared to all previous works using a similar composite crystal for dual wavelength operation.

Download or read book Fixed and Tunable Diode Lasers written by and published by Information Gatekeepers Inc. This book was released on with total page 58 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Diode Pumping of Average power Solid State Lasers written by Georg F. Albrecht and published by SPIE-International Society for Optical Engineering. This book was released on 1993 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Diode pumped Nd YLF lasers for high power operation written by Graham John Friel and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Semiconductor Laser Diode Pumps for Inertial Fusion Energy Lasers written by and published by . This book was released on 2011 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: Solid-state lasers have been demonstrated as attractive drivers for inertial confinement fusion on the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL) and at the Omega Facility at the Laboratory for Laser Energetics (LLE) in Rochester, NY. For power plant applications, these lasers must be pumped by semiconductor diode lasers to achieve the required laser system efficiency, repetition rate, and lifetime. Inertial fusion energy (IFE) power plants will require approximately 40-to-80 GW of peak pump power, and must operate efficiently and with high system availability for decades. These considerations lead to requirements on the efficiency, price, and production capacity of the semiconductor pump sources. This document provides a brief summary of these requirements, and how they can be met by a natural evolution of the current semiconductor laser industry. The detailed technical requirements described in this document flow down from a laser ampl9ifier design described elsewhere. In brief, laser amplifiers comprising multiple Nd:glass gain slabs are face-pumped by two planar diode arrays, each delivering 30 to 40 MW of peak power at 872 nm during a ≈ 200 [mu]s quasi-CW (QCW) pulse with a repetition rate in the range of 10 to 20 Hz. The baseline design of the diode array employs a 2D mosaic of submodules to facilitate manufacturing. As a baseline, they envision that each submodule is an array of vertically stacked, 1 cm wide, edge-emitting diode bars, an industry standard form factor. These stacks are mounted on a common backplane providing cooling and current drive. Stacks are conductively cooled to the backplane, to minimize both diode package cost and the number of fluid interconnects for improved reliability. While the baseline assessment in this document is based on edge-emitting devices, the amplifier design does not preclude future use of surface emitting diodes, which may offer appreciable future cost reductions and increased reliability. The high-level requirements on the semiconductor lasers involve reliability, price points on a price-per-Watt basis, and a set of technical requirements. The technical requirements for the amplifier design in reference 1 are discussed in detail and are summarized in Table 1. These values are still subject to changes as the overall laser system continues to be optimized. Since pump costs can be a significant fraction of the overall laser system cost, it is important to achieve sufficiently low price points for these components. At this time, the price target for tenth-of-akind IFE plant is $0.007/Watt for packaged devices. At this target level, the pumps account for approximately one third of the laser cost. The pump lasers should last for the life of the power plant, leading to a target component lifetime requirement of roughly 14 Ghosts, corresponding to a 30 year plant life and 15 Hz repetition rate. An attractive path forward involes pump operation at high output power levels, on a Watts-per-bar (Watts/chip) basis. This reduces the cost of pump power (price-per-Watt), since to first order the unit price does not increase with power/bar. The industry has seen a continual improvement in power output, with current 1 cm-wide bars emitting up to 500 W QCW (quasi-continuous wave). Increased power/bar also facilitates achieving high irradiance in the array plane. On the other hand, increased power implies greater heat loads and (possibly) higher current drive, which will require increased attention to thermal management and parasitic series resistance. Diode chips containing multiple p-n junctions and quantum wells (also called nanostack structures) may provide an additional approach to reduce the peak current.

Download or read book Diode pumped Alexandrite Laser Development and Vortex Mode Generation written by William Kerridge-Johns and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: