本文介绍了一种基于Yb:YAG薄盘再生放大器的高能,大功率光参量啁啾脉冲放大器泵源的操作协议。
这是关于100W,20mJ,1ps Yb:YAG薄盘再生放大器的报告。使用自制的Yb:YAG薄盘,具有交钥匙性能和微焦耳级脉冲能量的克尔透镜锁模振荡器来种子再生啁啾脉冲放大器。放大器放置在气密的外壳中。它在室温下工作,并以5 kHz的重复频率稳定运行,脉冲到脉冲的稳定性小于1%。通过使用1.5mm厚的β硼酸钡晶体,将激光输出的频率加倍至515nm,平均功率为70W,这对应于光学至光学效率的70%。这种卓越的性能使得该系统成为近红外和中红外光谱范围内的光参量啁啾脉冲放大器的有吸引力的泵浦源。结合再生放大器的交钥匙性能和卓越的稳定性,该系统有助于生成宽带,CEP稳定种子。从一个激光源提供光学参量啁啾脉冲放大(OPCPA)的种子和泵,消除了这些脉冲之间的活动时间同步的需求。这项工作提供了一个详细的指导,以建立和操作基于啁啾脉冲放大(CPA)的Yb:YAG薄盘再生放大器作为光参量啁啾脉冲放大器的泵浦源。
高能量的产生,以高重复率几周期的激光脉冲是非常感兴趣的应用领域,如阿秒科学1,2,3,4和高场物理5,6的哪个站到直接受益从这些来源的可用性。 OPCPA代表了实现高脉冲能量和大放大带宽的最有希望的途径,同时支持几个周期的脉冲1 。迄今为止,OPCPA允许超宽带放大,其产生几周期脉冲7,8,9,10。然而,OPCPA方案的修改实现,其使用短脉冲脉冲在皮秒级,具有希望使得这种方法可扩展为更高的脉冲能量,并在几个循环机制1,11,12平均功率。由于短脉冲泵浦OPCPA中的高泵浦强度,高单通道增益允许使用非常薄的晶体来支持大的放大带宽。虽然短脉冲泵浦OPCPA具有许多优点,但是这种方法的可实现性受到专门为此目的而定制的激光器的可用性。这种泵激光器在所需的重复率在kHz提供近衍射极限的光束质量高能量皮秒脉冲到MHz范围13,14,15。
引入镱掺杂激光器在不同的几何形状,能够提供高能量和高平均功率的皮秒激光脉冲,即将改变字段1,13,14,15,16,17,18的当前状态。 Yb:YAG具有良好的导热性和较长的上限寿命,可以通过成本效益的二极管激光器进行泵浦。由于增益介质的有效冷却同时缩放了峰值和平均功率,因此其在薄盘几何形状中的性能非常突出。此外,与其他增益介质几何形状相比,由于薄盘细长,因此在放大过程中增益介质内的自聚焦的发生被抑制,导致放大脉冲的优异的时间和空间分布。将这一概念与CPA相结合,可以产生具有数百毫焦耳的能量和数百的皮秒脉冲的平均功率19,20瓦。
这项工作的目的是展示一个交钥匙Yb:YAG薄盘再生放大器,具有卓越的日常性能,作为泵浦OPCPAs 21的合适来源。为了实现这一目标,本研究采用具有几微焦点脉冲能量的Yb:YAG薄盘振荡器22来种放大器以使放大过程中积累的非线性相位最小化。该协议提供了建立和操作激光系统的配方,这在其他地方描述21 。介绍了有关组件实现和控制软件的详细信息,介绍了系统的对齐过程。
振荡器的交钥匙操作是通过对激光器的不同部件的最佳热管理实现的。振荡器的输出可以每天重现,无需额外的对准或优化。此外,种子激光器的脉冲到脉冲能量稳定性和空间指向稳定性满足了实现再生放大器稳定运行的前提条件。
可以使用其他低能量种子源(例如光纤放大器)来种子放大器。在本研究中,使用2μJYb:YAG薄磁盘KLM振荡器来帮助放大再生放大器,通过减少积累的非线性相位的增长,因为对于较高输入的种子能量,所需的往返次数减少。此外,较高的种子能量影响放大过程并减少增益变窄。被测脉波的频谱带宽在固定的泵浦功率下用于不同的种子能量如图5c所示。由于增益变窄,放大的光谱带宽会降低较低的种子能量。对于10 pJ种子能量,激光器在倍增时间内运行,即使增加往返次数也不可能达到稳定运行。除了冷却系统和二极管的电源的仔细优化之外,再生放大器在饱和状态下的运行在实现放大器的稳定性方面起主要作用。
激光的基波或二次谐波可用于泵浦OPCPA系统。对于SHG,LBO和BBO晶体的性能进行了比较,因为它们具有高的非线性系数和损伤阈值,尽管在BBO的情况下具有较大的空间走向和有限的可用孔径。由于BBO的非线性系数几乎是LBO的两倍,所以较短的晶体是足够的以达到SHG的饱和极限( 图6a )。因此,BBO是更合适的选择,因为累积的非线性相位越小28。
SH脉冲的脉冲持续时间通过不同的转换效率实验表征。观察到,在高转换效率下,SHG光谱变宽并出现较高阶光谱相( 图6 )。因此,选择转换效率为70%的情况B,其中SH和未转换的基波束保持优良的质量。
The authors have nothing to disclose.
我们要感谢Ferenc Krausz教授的讨论和Najd Altwaijry的支持,以完成手稿。这项工作由高级激光应用中心(CALA)提供资金。
Electrooptics | |||
Fiber-Coupled Diode Laser Module | Dilas Diodenlaser GmbH | M1F8H12-940.5-500C-IS11.34 | |
Fiber-Coupled Diode Laser Module | Laserline GmbH | LDM1000-500 | |
Power Supply for Diode Laser | Delta Elektronika B.V. | SM 15-100 | |
Power Supply for Diode Laser | Delta Elektronika B.V. | SM 35-45 | |
Pulse Picker's Driver | Bergmann Messgeräte Entwicklung KG | N/A, customized | |
Pockels Cell's Driver | Bergmann Messgeräte Entwicklung KG | N/A, customized | |
Pulse Picker's Driver Power Supply | Bergmann Messgeräte Entwicklung KG | PCD8m7 | |
Pockels Cell's Driver Power Supply | Bergmann Messgeräte Entwicklung KG | PCD8m7 | |
Delay Generator PCI | Bergmann Messgeräte Entwicklung KG | BME_SG08p | |
Splitter Box | Bergmann Messgeräte Entwicklung KG | N/A, customized | |
Resonant Preamplifier | Bergmann Messgeräte Entwicklung KG | BME_P03 | |
Pulse Picker's crystal | Castech Inc. | N/A, customized | 12*12*20 mm³ |
Pockels Cell's crystal | Castech Inc. | N/A, customized | 12*12*20 mm³ |
Name | Company | Catalog Number | Comments |
Optics | |||
Thin-disk | TRUMPF Scientific Lasers | N/A, customized | |
Thin-disk Head | TRUMPF Scientific Lasers | N/A, customized | |
Fiber | Frank Optic Products GmbH | N/A, customized | |
Fiber Objective | Edmund Optics GmbH | N/A, customized | |
Faraday Isolator | Electro-Optics Technology, Inc | EOT.189.12231 | |
Faraday Rotator | Electro-Optics Technology, Inc | EOT.189.22040 | |
Stretcher's Grating 1 | Horiba Jobin Yvon GmbH | N/A, customized | 60*40*10 mm³ |
Stretcher's Grating 2 | Horiba Jobin Yvon GmbH | N/A, customized | 350*190*50 mm³ |
Compressor's Grating 1 | Plymouth Grating Laboratory, Inc. | N/A, customized | 40*40*16 mm³ |
Compressor's Grating 2 | Plymouth Grating Laboratory, Inc. | N/A, customized | 300*100*50 mm³ |
HR Mirror, 1" (1030nm), flat, 0° | Layertec GmbH | 108060 | |
HR Mirror, 1" (1030nm), flat, 0° | Laseroptik GmbH | B-09965, S-04484 | |
HR Mirror, 1" (1030nm), flat, 45° | Layertec GmbH | 108063 | |
HR Mirror, 1" (1030nm), flat, 45° | Laseroptik GmbH | B-09966, S-04484 | |
HR Mirror, 1" (1030nm), curved | Layertec GmbH | N/A, customized | set |
HR Mirror, 2" (1030nm), flat, 0° | Laseroptik GmbH | B-09965, S-05474 | |
HR Mirror, 2" (1030nm), flat, 45° | Laseroptik GmbH | B-09966, S-05474 | |
Thin Film Polarizer (1030nm), 2" | Layertec GmbH | 103930 | |
Waveplate L/2 (1030nm) | Layertec GmbH | 106058 | Ø=25mm |
Waveplate L/4 (1030nm) | Layertec GmbH | 106060 | Ø=25mm |
AR Window (1030nm), wedge | Laseroptik GmbH | B-00183-01, S-00988 | Ø=38mm |
Output Coupler, 1" (1030nm) | Layertec GmbH | N/A, customized | PR = 88 % |
High-dispersion Mirror (1030nm) | UltraFast Innovations GmbH | N/A, customized | GDD = -3000 fs² |
Lens, 1" (1030nm), Plano-Convex | Thorlabs GmbH | N/A, customized | set |
Lens, 1" (1030nm), Plano-Concave | Thorlabs GmbH | N/A, customized | set |
Lens, 2" (1030nm), Plano-Convex | Thorlabs GmbH | N/A, customized | set |
Lens, 2" (1030nm), Plano-Concave | Thorlabs GmbH | N/A, customized | set |
HR Mirror, 1" (515nm), flat, 0° | Layertec GmbH | 129784 | |
HR Mirror, 1" (515nm), flat, 0° | Eksma Optics | 042-0515-i0 | |
HR Mirror, 1" (515nm), flat, 45° | Layertec GmbH | 110924 | |
HR Mirror, 1" (515nm), flat, 45° | Eksma Optics | 042-0515 | |
HR Mirror, 1" (515nm), curved | Layertec GmbH | N/A, customized | set |
HR Mirror, 1" (515nm), curved | Eksma Optics | N/A, customized | set |
HR Mirror, 2" (515nm), flat, 0° | Eksma Optics | 045-0515-i0 | |
HR Mirror, 2" (515nm), flat, 45° | Eksma Optics | 045-0515 | |
Thin Film Polarizer (515nm), 2" | Layertec GmbH | 112544 | |
Waveplate L/2 (515nm) | Layertec GmbH | 112546 | Ø=25mm |
Lens, 1" (515nm), Plano-Convex | Thorlabs GmbH | N/A, customized | set |
Lens, 1" (515nm), Plano-Concave | Thorlabs GmbH | N/A, customized | set |
Kerr Medium | Meller Optics, Inc. | N/A, customized | Sapphire, 1mm |
BBO Crystal | Castech Inc. | N/A, customized | 7*7*1.5 mm³ |
Harmonic Separator, 1", 45° | Eksma Optics | 042-5135 | |
Harmonic Separator, 2", 45° | Eksma Optics | 045-5135 | |
Silver Mirror, 1", flat | Thorlabs GmbH | PF10-03-P01 | |
Silver Mirror, 1", curved | Eksma Optics | N/A, customized | set |
Filter – Absorptive Neutral Density | Thorlabs GmbH | NE##A | set |
Filter – Reflective Neutral Density | Thorlabs GmbH | ND##A | set |
Filter – Round Continuously Variable | Thorlabs GmbH | NDC-50C-4M | |
Filter – Edgepass Filter (Longpass) | Thorlabs GmbH | FEL#### | set |
Filter – Edgepass Filter (Shortpass) | Thorlabs GmbH | FES#### | set |
Wedge | Thorlabs GmbH | N/A, customized | set |
Name | Company | Catalog Number | Comments |
Optomechanics & Motion | |||
Mirror Mount 1" (small) | S. Maier GmbH | S1M4-##-1” | |
Mirror Mount 1" (large) | S. Maier GmbH | S3-## | |
Mirror Mount 1" | TRUMPF Scientific Lasers | 1" adjustable | |
Mirror Mount 2" | S. Maier GmbH | S4-## | |
Mirror Mount 2" | TRUMPF Scientific Lasers | 2" adjustable | |
Rotation Mount 1” | S. Maier GmbH | D25 | |
Rotation Mount 1” | Thorlabs GmbH | RSP1/M | |
Rotation Mount 2” | Thorlabs GmbH | RSP2/M | |
Precision Rotation Stage | Newport Corporation | M-UTR120 | |
Four-Axis Diffraction Grating Mount | Newport Corporation | DGM-1 | |
Translation Stage | OptoSigma Corporation | TADC-651SR25-M6 | |
Pockels cell stage | Newport Corporation | 9082-M | |
Pockels Cell Holder | Home-made | N/A, customized | |
Picomotor Controller/Driver Kit | Newport Corporation | 8742-12-KIT | |
Picomotor Piezo Linear Actuators | Newport Corporation | 8301NF | |
Picomotor Rotation Mount | Newport Corporation | 8401-M | |
Hand Control Pad | Newport Corporation | 8758 | |
Name | Company | Catalog Number | Comments |
Light Analysis | |||
Beam Profiling Camera | Ophir Optronics Solutions Ltd | SP620 | |
Beam Profiling Camera | DataRay Inc. | WCD-UCD23 | |
Photodiodes (solw) | Thorlabs GmbH | DET10A/M | |
Photodiodes (fast) | Alphalas GmbH | UPD-200-SP | |
Thin-disk Camera | Imaging Development Systems GmbH | UI-2220SE-M-GL | |
Oscilloscope | Tektronix GmbH | DPO5204 | |
Oscilloscope | Teledyne LeCroy GmbH | SDA 760Zi-A | |
Spectrometer | Avantes | AvaSpec-ULS3648-USB2 | |
Spectrometer | Ocean Optics, Inc | HR4C1769 | |
Spectrometer | Ocean Optics, Inc | HR4C3762 | |
Spectrometer | Ocean Optics, Inc | HR4D464 | |
Spectrometer | Ocean Optics, Inc | HR4D466 | |
Laser Thermal Power Sensor | Ophir Optronics Solutions Ltd | L50(150)A-PF-35 | |
Laser Thermal Power Sensor | Ophir Optronics Solutions Ltd | FL500A | |
Laser Thermal Power Sensor | Ophir Optronics Solutions Ltd | 3A-P-V1 | |
Power and Energy Meter | Ophir Optronics Solutions Ltd | Vega | |
Name | Company | Catalog Number | Comments |
Systems | |||
Laser Beam Stabilization System | TEM-Messtechnik GmbH | Aligna | |
Laser M² Measuring System | Ophir Optronics Solutions Ltd | M²-200s | |
FROG | Home-made | N/A, customized | |
XFROG | Home-made | N/A, customized | |
Name | Company | Catalog Number | Comments |
Miscellaneous | |||
Cooling Chiller | H.I.B Systemtechnik GmbH | 6HE-000800-W-W-R23-2-DI | |
Cooling Chiller | Termotek GmbH | P201 | |
Cooling Chiller | Termotek GmbH | P208 | |
Laser Safety Goggles | Protect – Laserschutz GmbH | BGU 10-0165-G-20 | |
Infra-red Viewer | FJW Optical Systems | 84499A | |
Laser Viewing Card | Thorlabs GmbH | VRC4 | |
Laser Viewing Card | Thorlabs GmbH | VRC5 | |
Laser Viewing Card | Laser Components GmbH | LDT-1064 BG | |
Flowmeter | KOBOLD Messring GmbH | DTK-1250G2C34P | |
Pressure Gauge | KOBOLD Messring GmbH | EN 837-1 | |
Temperature Sensor | KOBOLD Messring GmbH | TDA-15H* ***P3M | |
WinLase Software | Dr. C. Horvath & Dr. F. Loesel | WinLase Version 2.1 pro. | Laser Cavity Software |