Hansel Thomas, Steinmeyer Günter, Grunwald Ruediger, Falldorf Claas, Bonitz Jens, Kaufmann Christian, Kebbel Volker, Griebner Uwe
Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, Max-Born-Str. 2a, 12489 Berlin, Germany.
Opt Express. 2009 Feb 16;17(4):2686-95. doi: 10.1364/oe.17.002686.
A dual-wavelength femtosecond laser pulse source and its application for digital holographic single-shot contouring are presented. The synthesized laser source combines sub-picosecond time scales with a wide reconstruction range. A center wavelength distance of the two separated pulses of only 15 nm with a high contrast was demonstrated by spectral shaping of the 50 nm broad seed spectrum centered at 800 nm. Owing to the resulting synthetic wavelength, the scan depth range without phase ambiguity is extended to the 100-microm-range. Single-shot dual-wavelength imaging is achieved by using two CMOS cameras in a Twyman-Green interferometer, which is extended by a polarization encoding sequence to separate the holograms. The principle of the method is revealed, and experimental results concerning a single axis scanner mirror operating at a resonance frequency of 0.5 kHz are presented. Within the synthetic wavelength, the phase difference information of the object was unambiguously retrieved and the 3D-shape calculated. To the best of our knowledge, this is the first time that single-shot two-wavelength contouring on a sub-ps time scale is reported.
介绍了一种双波长飞秒激光脉冲源及其在数字全息单次轮廓测量中的应用。合成激光源将亚皮秒时间尺度与宽重建范围相结合。通过对以800nm为中心的50nm宽种子光谱进行光谱整形，展示了两个分离脉冲的中心波长距离仅为15nm且具有高对比度。由于产生的合成波长，无相位模糊的扫描深度范围扩展到了100微米范围。在泰曼-格林干涉仪中使用两个CMOS相机实现单次双波长成像，该干涉仪通过偏振编码序列扩展以分离全息图。揭示了该方法的原理，并给出了关于在0.5kHz共振频率下运行的单轴扫描镜的实验结果。在合成波长范围内，明确检索到了物体的相位差信息并计算出了三维形状。据我们所知，这是首次报道在亚皮秒时间尺度上的单次双波长轮廓测量。
