Encoding and decoding of amplitude or phase informations with a liquid-crystal array on femtosecond light pulses

使用飞秒光脉冲上的液晶阵列对幅度或相位信息进行编码和解码

基本信息

批准号：
07650401
负责人：
KANNARI Fumihiko
金额：
$ 1.28万
依托单位：
Keio University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

项目摘要

1. Arbitrarily shaped femtosecond laser pulses are produced with a Fourier-transform synthesis using a commercially available liquid-crystal spatial light modulator (SLM) controlled by a IBM-PC.The modulator consists of 128 individually programmable pixels of 100 mum wide with a 3 mum gap between each elements. The pulse-shaping apparatus consists of a grating pair placed at the focal planes of a unit magnification confocal lens-pair with a focal length of 15cm.(1) Phase-only masks formed with the SLM in the experiments were designed with simulated annealing optimization algorithm for arbitrarily shaped amplitude and phase time histories. Even asymmetric shapes in time domain can be synthesized with four gray levels of 0, (]SY.+-。[)pi/2, and pi.(2) Successful shaping of -100 fs input laser pulse was obtained in our experiments such as THz pulse trains shaped with 7-length M-sequence, unsymmetrical pulse trains, and linearly frequency-chirped pulses.2. Selective coherent phonon mode was excited in Bi with THz pulse trains synthesized with our pulse shaping apparatus.3. Utilizing this pulse shaping apparatus, we succeeded to shape coherent function of a cw light from a super luminescent diode with a spectrum width of -17nm.4. Multiplexed holograms were recorded with spatial phase encoding method as a preliminary experiments of femtosecond spectrum holography. Holograms recorded by a beam encoded with a quasi-noise phase pattern and a single lobe formation pattern, successfully produce a single lobe beam pattern only when a read beam is encoded with the same quasi-noise phase pattern.

1。使用IBM-PC控制的市售液晶空间光调制器（SLM），使用傅立叶转换合成的傅立叶转换合成，由IBM-PC控制。调节器由128个单独编程的像素宽，每种元素之间的3个妈妈宽。脉冲形状设备由一个栅格对组成，位于单位放大倍率共焦晶状体对焦平面上，焦距为15厘米。（1）在实验中使用SLM形成的仅相位掩模，使用模拟的退火优化算法，用于任意形状的放大器和相位时间均衡器。即使是时间域中的不对称形状，也可以用四个灰色水平为0，（]sy。+ - 。[）pi/2和pi。（2）在我们的实验中成功形成-100 fs输入激光脉冲，如我们的THZ脉冲序列，如7长度的M-序列M-序列脉冲，无效的脉冲序列，linmememes pulseS pulse pulse cyserme-cchirlys-cchirlys和linmelys-cchirs和linmelys-chirs和linmelys-chirs-cchirs和linsermens-cchirs和linmenly频率。选择性相干的声子模式在BI中激发了与我们的脉冲成型设备合成的THZ脉冲序列3。利用这种脉冲成型设备，我们成功地从频谱宽度为-17nm.4的超级发光模具中塑造了CW光的相干功能。用空间相编码方法记录多重全息图作为飞秒频谱全息图的初步实验。全息图由横梁记录，并用准噪声相模式和单个叶片形成模式进行编码，仅当读取梁用相同的准噪声相模式编码时才能成功产生单个叶片梁图案。