共查询到20条相似文献,搜索用时 46 毫秒
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Chu Liu Fan Zhang Chun-can Wang Yu-chun Lu Rui Geng Shui-sheng Jian 《Optical Review》2009,16(5):529-532
A new method for the wavefront measurement of high power laser diode array with large dynamic ranges is presented. The wavefront
sensor has a large dynamic range of −π/2 to π/2 and high precision on the measured wavefront slopes (±1′). According to the measurements of the slopes and intensity of
the high power laser diode array, complex amplitudes can be obtained and the wavefront can be reconstructed. The reconstructed
wavefront of high power laser diode array can be used in designing a laser beam shaping system in future work. 相似文献
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大口径光学元件中频波前的准确评价已成为高功率激光系统中关注的焦点,元件中频波前均方根值是重要评价指标之一。根据波前中频检测频段及波前检测设备频响特性,将波前的中频区域分为两个检测频段,分别采用干涉仪和光学轮廓仪实现了中频波前均方根值的检测。采用大口径干涉仪可实现全口径波前中频区域低频段波前的检测,通过比对大口径干涉仪和采用小口径干涉仪结合分块融合平均方法的检测结果,提出采用分块融合平均方法也可检测相应频段全口径波前均方根。采用光学轮廓仪通过离散采样的方法检测大口径元件中频区域高频段波前均方根,针对不同离散采样方式的实验结果表明:33的采样方式能满足对410 mm410 mm口径元件中频区域高频段波前均方根的检测。 相似文献
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The collimation of strongly diverging laser beams emitted by high-power diode lasers is performed with aspherical micro-optical components which have large numerical apertures up to NA=0.7. Conventional interferometric techniques do neither deliver the resolution nor the test frequency and are too costly for an industrial application.Digital holography is presented as a measurement tool for the characterization of micro-optical components in this paper providing a robust and fast technique with a simple and compact setup.The setup presented in this contribution does not apply any imaging or magnifying optics thus avoiding any additional aberrations in the wavefront which would falsify the measurement. The reconstruction process is performed in the computer giving direct access to intensity and phase of the measured wavefront. Additional experimental efforts like, e.g. phase shifting techniques are not needed.The large numerical aperture of the microlenses leads to high fringe densities in the holograms which cannot be resolved by CCD-detectors directly. In order to avoid this problem digital holography is combined with a multiple wavelength technique and a diffusing screen to capture the highly diverging wavefront. An averaging method to reduce the introduced speckle noise is applied and results of the characterization of refractive cylindrical microlenses are presented. 相似文献
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用Hartmann-Shack(H-S)波前传感器可以准确测量穿过超声速流场的激光波面及其变化过程,进一步计算可以获得光束质心漂移、远场分布等数据。给出了H-S方法测量穿过超声速流场激光波面的原理,采用模式法进行了波前重构,计算了在几种流场条件下的激光波面像差特性PV值,RMS值和Zernike像差系数、Strehl比和环围能量曲线等。结果表明,H-S法可以很好地反映流场建立、稳定和结束过程中Zernike像差的变化。比较无流场和给定参数的超声速流场,激光穿越后产生的最明显的像差变化为离焦和低阶像散的增大。在相同流场参数下,无模型时光束质量好于有模型时光束质量。 相似文献
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Luigi Zeni Stefania Campopiano Antonello Cutolo Giuseppe DAngelo 《Optics and Lasers in Engineering》2003,39(2):203-217
Nowadays, power semiconductor laser diode arrays are becoming a widespread source for a large variety of industrial applications. In particular, the availability of low-cost high-power laser diode arrays makes their use possible in the industrial context for material cutting, welding, diagnostics and processing. In the above applications, the exact control of the beam quality plays a very important role because it directly affects the reliability of the final result. In this paper, we present two different approaches useful for the characterization of the beam quality in laser diode arrays. The first one, starting from total intensity measurements on planes orthogonal to the beam propagation path, is able to deduce the working conditions of each laser setting up the array. The second one is aimed at the measurement of a global quality factor of the array itself; to this end, the empirical extension of the M2 concept to composite beams is presented along with some experimental results. As the first technique is especially intended for the non-destructive detection of design problems in the array itself and in the bias circuitry, the second one represents a powerful tool for the rapid on-line diagnostics of the laser beam during its use. 相似文献
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A method of direct measurement of near-field phase and intensity distribution of laser diodes employing a single-mode fiber interferometer is proposed and demonstrated. The phase and intensity of the output beam of the laser in the vicinity of the output facet are measured directly via interferometry. Using a 980 nm laser diode as an example, we obtained a beam width of 0.9 and 3.6 μm at the output facet in the vertical and horizontal axes, respectively. In addition, the phase information of the output beam was also obtained by using interferometry. This technique is particularly useful for laser diodes whose near-field phases are difficult to measure directly. The measured vertical and horizontal wavefront radius of curvatures of a laser diode are in good agreement with the calculation from Gaussian beam theory. Detailed understanding and measurement of the near-field phase and intensity distributions of light sources and optical components are essential for micro-optic designs with better mode matching to minimize the insertion loss. 相似文献
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The beams of four pulsed high-power laser diodes are time-multiplexed resulting in a laser beam of high quality. A combination of polarization switches and filters forming a digital time-multiplexer is utilized to guide laser pulses produced by the individual laser diodes onto a common optical path. A resulting beam with an optical power of 10 W and a beam quality comparable with that of a single laser diode at a wavelength of 960 nm is obtained. 相似文献
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Theoretical and experimental studies on high-power laser-induced thermal blooming effect in chamber with different gases 下载免费PDF全文
Xiangyizheng Wu 《中国物理 B》2022,31(8):86105-086105
High-power laser induced thermal blooming effects in a closed chamber with three different gases are investigated theoretically and experimentally in this work. In the theoretical treatment, an incompressible gas turbulent model is adopted. In the numerical simulation the gas refractive index as a function of both the temperature and pressure is taken into consideration. In the experimental study the pump-probe technology is adopted. A high-power 1064-nm fiber laser with maximum output power of 12 kW is used to drive the gas thermal blooming, and a 50-mW high-beam-quality 637-nm laser diode (LD) is used as a probe beam. The influences of the gas thermal blooming in the chamber on the probe beam wavefront and beam quality are analyzed for three different gases of air, nitrogen, and helium, respectively. The results indicate that nitrogen is well suitable for restraining thermal blooming effect for high-power laser. The measured data are in good agreement with the simulated results. 相似文献
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We report on an optical beam produced by superimposing radially- and circularly-polarized laser beams for active control of the location of the beam's intensity. The asymmetric intensity distribution relative to the beam's central axis, and its location is determined by the relative phase difference between the two beams. Since the beam has a planar wavefront, it carries no orbital angular momentum, yet it shares phase singularity and spiral interference characteristics commonly associated with helical wavefronts. Such an optical beam is valuable for applications in optical–optical switches and routers, optical steering, and also optical trapping and rotation, or driving opto-micromachines. 相似文献
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精确的波前探测是反射镜面型检测及光束波前畸变测量的重要依据,论文根据Shark-Hartmann理论对波前探测技术进行了模拟和实验研究。将平行光经过球面透镜/柱面透镜后形成的球面波/柱面波作为探测波前。实验采用商用的微透镜阵列和CCD搭建Shark-Hartmann传感器,利用实际光束作为参考光,避免了参考光的不准直性对实验的影响。模拟计算结果表明平均曲率误差为13.423 mm,实验结果实现了对球面/柱面/倾斜波的探测及复原。 相似文献
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为获得高功率高光束质量的激光器,对激光器中的热致球差进行了研究。介绍了高功率二极管泵浦Nd:YAG棒激光模块热致球差的测量和补偿方法。使用S-H波前探测器测量了激光模块的三阶球差,设计了补偿系统对激光模块的球差进行了补偿,并对补偿前后的各阶像差进行了分析。在主振功放(MOPA)系统中使用球差补偿系统,工作电流110 A时,光束质量平方因子从9.2提高到6.4。实验结果表明球差补偿系统能消除激光模块的的三阶球差,而且不会引起其它像差的增大,提高了激光器光束质量。 相似文献
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We present a Shack-Hartmann wavefront sensor (SHWS) based on a cylindrical microlens array as a device for measuring highly aberrated wavefronts. Instead of the typical spot pattern created by a conventional SHWS, two orthogonal line patterns are detected on a CCD and are superimposed. A processing algorithm uses the continuity of the focal line to extend the dynamic range of measurement by localizing the line, even if it leaves the CCD area confined by the corresponding microcylinder. The measurement of a wavefront from a progressive addition lens with an 80 lambda peak-to-valley value reveals the capabilities of the sensor. 相似文献
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We describe effective suppression of beam divergence for a high-power laser diode bar by use of an external-cavity technique. Nineteen off-axis external-cavity laser diodes of the high-power laser diode are formed by feedback with a stripe mirror. At three times the threshold current, the diverging angle (1/e2) of the external-cavity laser diode bar is reduced to 1.5 degrees from 6.6 degrees (free running) with 14.1-W peak output power and 70.4% of the radiated power of the free-running state without the external cavity. This technique effectively improves the beam quality of the high-power laser diode bar. 相似文献
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Marek Dobosz Hirokazu Matsumoto Katuo Seta Shigeo Iwasaki 《Optics and Lasers in Engineering》1996,24(1):43-56
Superposition of different-wavelength, multimode- and single-mode laser diode beams is investigated to locate the fringe of zero interference order in a Twyman-Green interferometer. The possibility of central fringe detection using three multimode laser diodes or one single-mode together with a pair of multimode laser diodes is shown. If a single-mode laser diode is applied, a simultaneous fringe-counting technique for displacement measurement is available. The influence of the angle between wavefronts entering the interferometer is analyzed. A repeatability of about 5 nm is shown for surface position determination when using three-beam source. 相似文献
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Narrow bandwidth operation of high-power broad-area diode laser using cascaded phase-conjugate injection locking 总被引:1,自引:0,他引:1
H. Horiuchi T. Shimura T. Omatsu O. Matoba K. Kuroda 《Applied physics. B, Lasers and optics》1999,68(5):1021-1025
A broad-area laser is injection-locked by another broad-area laser that is also injection-locked by a single-mode diode laser.
Two double-phase conjugate mirrors of photorefractive BaTaO3 are used to couple the master laser beams to the first slave laser, and the first slave laser output to the second slave
laser. One of the double-phase conjugate mirrors is built up with the beams from two broad-area lasers. Two slave lasers are
oscillating in single longitudinal mode at 808.5 nm and the spectral width is the same as that of the master laser. Final
single-mode output power from the second slave broad-area laser is 840 mW, which is limited by the power of the injection
beam. This work verifies the possibility of the multi-stage cascaded injection locking of high-power diode lasers with phase-conjugate
injection.
Received: 18 November 1998 / Revised version: 29 January 1999 / Published online: 7 April 1999 相似文献
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利用波前传感器测量自由曲面镜片时,由于自由曲面镜片的直径通常大于波前传感器的接收孔径,主要采用子孔径拼接技术测量镜片的波前像差。针对子孔径拼接技术测量中存在着操作繁琐、数据处理量大等问题,提出渐进多焦点镜片波前像差的扩束测量方法,得到渐进多焦点镜片中央直径为22 mm圆形区域内的波前像差。为了验证试验的可靠性,将测量得到的波前像差泽尼克表述中的离焦项转换为球镜度,与条纹偏折法测量得到镜片的球镜度进行对比实验,实验结果证明了渐进多焦点镜片波前像差的扩束测量方法可以用于渐进多焦点镜片波前像差的检测。 相似文献