Question

急!!谁英语好棒我翻译篇文章！不要用GOOGLE之类的直接翻译！！

Fig. 1. Grating interferometer for f latness testing. G1
diffracts the source light into two beams, A and B, and
G2 brings them back together again at the object surface.
The sensitivity of the interferometer to surface deformation
is caused by the difference in the incident angles of beams
A and B on the object surface.
The equivalent wavelength of the interference fringes
is independent of the source wavelength l. The interference
pattern is achromatic and is not limited by the
temporal coherence properties of the source light.
Achromatic fringe formation is characteristic of
moir´e interferometry, which is generally interpreted
geometrically. It is possible to analyze the properties
of the interferometer shown in Fig. 1 in the same
way. The key to the geometric interpretation is the
notion that grating G2 creates an achromatic image
of grating G1 on the object surface. The production
of a fine-grain achromatic line pattern with a grating
pair was studied extensively by Chang et al.3 Viewed
from this perspective, grating G2 may be thought of as
a very high-numerical-aperture lens with conjugates
at G1 and the object plane. The interpretation of
the resulting interference pattern in the image plane
is indeed similar to that of projection moir´e with an
unusually fine-pitch grating.
Whatever the physical interpretation of the interference
phenomenon, the grating interferometer in
Fig. 1 has considerable practical merit. The equivalent
wavelength L for most practical combinations of
gratings ranges from 4 to 40 mm, so the instrument
sensitivity is intermediate between visible-wavelength
interferometry and geometric optics. The slope tolerance
and the acceptable surface roughness are correspondingly
increased with respect to conventional
interferometry. The fringe contrast is excellent since
both of the interfering beams ref lect off the object, and
the intensity balance is nearly independent of the surface
ref lectivity. Because the fringes are achromatic
the source-wavelength stability is irrelevant, and conventional
incandescent sources generate clear colorless
fringes. The insensitivity to source wavelength is also
a benefit when one is using laser-diode sources, which
tend to be unstable spectrally.
Figure 2 shows experimental phase data for a
grating interferometer having an equivalent wavelength
L of 8 mm. The object surface shown in
Fig. 2 is a 30-mm-diameter portion of a sheet of
brush-finished aluminum having a rms surface
roughness of 0.4 mm. The gratings for this interferometer
are 75 nm in diameter, the frequency
N1 is 300 groovesymm.

Answer 1

图。 1。光栅对f latness测试干涉。 G1期
折射两源的光束，A和B，以及
G2使他们重新结合在一起的物体表面。
干涉的地表变形的敏感性
是由在入射角差异造成的梁
A和B的物体表面。
等效的干涉条纹波长
独立源波长湖干扰
模式是无色，不受有限
源光时间相干性的属性。
消色差边缘形成的特点是
moir'e干涉，这是一般解释
几何。这是可能的属性分析
在图所示的干涉。 1在同一
方式。到几何解释的关键是
光栅G2观念，创建一个色差形象
光栅G1期的物体表面。生产
一种细粒度色差线模式与光栅
研究了对Chang等al.3广泛阅读
从这个角度看，光栅G2可能被认为是
一个非常高的数值与偶联光圈镜头
在G1和对象的飞机。的解释
在图像平面产生的干涉条纹
的确类似预测moir'e，随
异常精细间距光栅。
无论干扰物理解释
现象，在光栅干涉仪
图。 1有很多实际的好处。等效
波长L的最实际的组合
光栅范围从4到40毫米，这样的仪器
敏感性是介于可见光波长
干涉测量法和几何光学。宽容的斜坡
和可接受的表面粗糙度也相应
加强了有关常规
干涉。边缘对比非常好，因为
两方面的干扰梁参考图法关闭对象，
强度平衡几乎是独立的表面
参考lectivity。由于边缘，色差
源波长稳定是无关紧要的，与常规
白炽灯源生成无色
条纹。源波长的敏感性也
1当一个好处是使用激光，二极管来源，
往往是不稳定的光谱。
图2显示了一个试验阶段的数据
光栅干涉仪具有等效波长
L的8毫米。在物体表面显示
图。 2是一个30毫米直径的表中的一部分
刷半成品铝表面有一个有效值
粗糙度为0.4毫米。这干涉的光栅
在直径75纳米的频率
N1是300 groovesymm