b*******2
发帖数: 2121 | 1 这是个基本问题,可是却困扰我很久,一直搞不明白.请高人指教.
(1).根据EM wave 理论里面的定义:
# TE modes: no electric field in the direction of propagation.
# TM modes: no magnetic field in the direction of propagation.
这个很容易理解,就是它们的定义.
(2). 在学习Polarization 的时候,有S and P Polarization 的定义.
P-Polarization: The component of the electric field parallel to incident
plane is termed p-like (parallel)
S-Polarization: component perpendicular to this plane is termed s-like.
这个我也能理解. 是s- 和 p- pol 的定义.
wiki中还有如下定义: Light with a p-like electric field is said to be p-
polarized, or transverse-magnetic (TM) wave; Light with an s-like electric
field is s-polarized, or transverse-electric (TE) wave.
这好像是在说(p-pol=TM; s-pol=TE)? 人们在谈论polarization 的时候也经常用TE
and TM polarization, 这就让我糊涂了. 按我理解, (1)中定义的TE TM mode 只是电
磁波的特性,其中没有涉及到偏振的含义. 那么(2)中定义的TE 和TM wave, 和(1)中的
TE TM 是不是一个意思? 它们有什么联系? 为什么p- polarized light 就是TM wave??
非常感谢. | a*****e
发帖数: 4577 | 2 具体情况具体分析
你说的TE/TM到底是在什么情况下的？
【在 b*******2 的大作中提到】
: 这是个基本问题,可是却困扰我很久,一直搞不明白.请高人指教.
: (1).根据EM wave 理论里面的定义:
: # TE modes: no electric field in the direction of propagation.
: # TM modes: no magnetic field in the direction of propagation.
: 这个很容易理解,就是它们的定义.
: (2). 在学习Polarization 的时候,有S and P Polarization 的定义.
: P-Polarization: The component of the electric field parallel to incident
: plane is termed p-like (parallel)
: S-Polarization: component perpendicular to this plane is termed s-like.
: 这个我也能理解. 是s- 和 p- pol 的定义.
| b*******2
发帖数: 2121 | 3 我想问的是,(1) 和(2)中定义所说的TE TM 是不是同一个意思?
【在 a*****e 的大作中提到】
: 具体情况具体分析
: 你说的TE/TM到底是在什么情况下的？
| a*****e
发帖数: 4577 | 4 no
【在 b*******2 的大作中提到】
: 我想问的是,(1) 和(2)中定义所说的TE TM 是不是同一个意思?
| c**e
发帖数: 4439 | 5 TE TM 有的时候 正好是反的 所以看具体情况 | j****1
发帖数: 15 | 6 这个很多情况下定义是有点模糊 不过大家讲的都是同一个structure的时候说起来都明
白指的是什么就行了 也就一个名字
【在 b*******2 的大作中提到】
: 这是个基本问题,可是却困扰我很久,一直搞不明白.请高人指教.
: (1).根据EM wave 理论里面的定义:
: # TE modes: no electric field in the direction of propagation.
: # TM modes: no magnetic field in the direction of propagation.
: 这个很容易理解,就是它们的定义.
: (2). 在学习Polarization 的时候,有S and P Polarization 的定义.
: P-Polarization: The component of the electric field parallel to incident
: plane is termed p-like (parallel)
: S-Polarization: component perpendicular to this plane is termed s-like.
: 这个我也能理解. 是s- 和 p- pol 的定义.
| f*******a
发帖数: 80 | 7 The concepts of TE and TM mode vary depending on the context.
a) If you talk about the plane wave propagating in the free space, the
electromagnetic wave is a transverse wave, i.e. the direction of the
electric field and magnetic field are perpendicular to the direction of wave
propagation. This is in contrast to elastic wave, in which the direction of
partical flow can be either perpendicular or parallel to the direction of
propagation. In this context, we don't talk about the mode.
b) Electromagnetic wave can propagate in waveguides. In this case, there are
modes, waves associated with different eigen values of the Helmholtz
equation depending on the geometry/material of the waveguide. If the wave
has no electric field in the direction of propagation, it is called the TE
mode, ie. electric field is transverse to the direction of propagation.
c) There are also discussions on the radiated field by a infinitely long
current source. The radiated wave by this current source contains the
electric field parallel to the current source and perpendicular to the
cylindrical spreading. However, people also call this the TM mode. This
might be due to the fact that the TM mode in waveguide as in (b) can be
constructed from them. |
|
