双棱镜

For initializing the reference quantity of Bragg wavelength, the vertex angles of the biprism are determined by the 1 diffraction angle of phase mask and the refract index of the biprism.

为了初始化Bragg波长的参考值，双光栅的顶角由相位掩模的1级衍射角和双棱镜的折射率确定。

In this system, the gratings are inscribed by the UV interference fringes of 248 nm derived from a rotatable biprism, where the phase mask is used as a beam splitter, and the biprism is rotated to change the intersection angle of two beams.

在该系统中，光纤光栅是由来自可旋转双棱镜所形成的波长为248 nm的紫外干涉条纹写入的，其中，相位掩模被用作1级衍射光的分束器，通过双棱镜的旋转可改变两写入光束的交叉角。

The results show, when the prism wedge angle is 4°, the transmitted laser beam changes about 1 μrad as the prism rotates 1′; when the small angle deviation on one side of the minimum deviation angle of each prism is controlled, the scanning range of laser beam in the horizontal and vertical direction is not less than 500 μrad, and the scanning precision of the device is superior to 0.2 μrad.

结果表明：取棱镜棱角α为4°时，棱镜每旋转1′，透射光束变化约1 μrad；分别控制双棱镜在其最小偏向角一侧小角度偏转，可以实现光束在水平方向和垂直方向500 μrad范围内的精确扫描，装置的扫描精度可以达到0.2 μrad。

Based on the full-width at half-maximum of optical pulse,one can estimate the radius of incident beams and Fresnel biprism's base angle.

根据所测飞秒脉冲的半高全宽，可估算所需光斑大小和菲涅尔双棱镜底角，为菲涅尔双棱镜的选择提供了理论依据。

A rotatable biprism is introduced in phase mask technique to change the inscribed Bragg of grating.

将一种可旋转的双棱镜引入到相位掩模技术中以改变光栅的写入Bragg波长。

Measuring light wavelength with biprism interference is a very important experiment in the research and teaching of basic physics, the key to which is the distance measurement of the two virtual images.

用双棱镜干涉测量光波波长是基础物理研究和教学中非常重要的一个实验，该实验的关键环节是测量两虚相干光源间的距离，大多数实验教科书中大都采用二次成像法测量两虚相干光源的间距。

Because the change of grating period caused by the asymmetrical rotation of two beams is limited to 5×10-4 nm at a tunability of the Bragg wavelength of ~100 nm, the tilt of grating caused by the rotation of the biprism can be ignorable.

因为在~100 nm范围内两光束的非对称旋转对光栅周期的改变是5×10-4 nm，双棱镜引入的光栅的闪耀可忽略。

Meanwhile,the relation among Fresnel biprism's base angle,refractive index,and the radius of incident femtosecond pulse beam was obtained.

基于单发频率分辨光学开关法的飞秒脉冲测量系统，理论推导光束经菲涅尔双棱镜分光与聚合产生的时间延迟，得到菲涅尔双棱镜底角、折射率和脉冲光斑半径的关系。

A composed rhomboid prism composed of two isotropic left-handed material prisms with an uniaxially anisotropic LHM plate,there is an angle between the interface of which and the optical axis, was designed.

设计了一种左手材料复合双棱镜，由两块各向同性左手材料棱镜与夹在其间的、其界面与光轴成一定的角度的单轴各向异性左手材料平板构成。

A composed rhomboid prism composed of two isotropic left-handed material prisms with an uniaxially anisotropic LHM plate,there is an angle between the interface of which and the optical axis, was designed.

左手材料复合双棱镜内部界面的古斯-汉森位移，设计了一种左手材料复合双棱镜，由两块各向同性左手材料棱镜与夹在其间的、其界面与光轴成一定的角度的单轴各向异性左手材料平板构成。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。