Polarization of light

Содержание и основные понятия

Polarization describes the orientation of the fluctuations in the electric field; it proves the transverse nature of the light and is used to control the lights and contrasts.
GEF · 11 grade
PIF · Baseline
Interactive model
polarization
Polesizer
Analyzer
Double radius
01
The physical picture
What happens and what boundaries the model has.
Main message
Polarization describes the orientation of the fluctuations in the electric field; it proves the transverse nature of the light and is used to control the lights and contrasts.
Natural light is usually not polarized.
The polarizer passes the component field along its axis.
The two perfect polarizers that are crossed are barely missing light.
How to reason
First, name the system and the interaction, then select the values, and only then write down the law. The formula works within the model's assumptions.
02
Laws and values
Symbols should be read as a relationship of values, not as a recipe for substitution.
I
=
I
0
cos
⁡
2
α
I=I_0\cos^2\alpha
I
=
I
0
​
cos
2
α
Malus law
I
=
I
ест
2
I=\frac{I_{\text{ест}}}{2}
I
=
2
I
eats.
​
​
after the first polarizer
Review of the situation
Polarized glasses reduce horizontal polarized lights from water and road.
04
Links and application
In the real world
Polarized glasses reduce horizontal polarized lights from water and road.
Model verification
Compare the prediction with observation, evaluate the units, the order of magnitude and the influence of the factors not taken into account. Disparity does not always mean an error of law: often idealization is no longer sufficient.
C
What needs to be understood
Outcome 1
Explain the physical meaning of the topic "Polarization of light" through the model, not just through the formula.
Outcome 2
Distinguish and correctly use terms: polarization, polarizer, analyser.
Outcome 3
Indicate the conditions for the applicability of the law, verify units and limit cases.
T
Terms of the topic
The definition should indicate the physical meaning, not a substitute for a domestic synonym.
polarization
Streamlining the orientation of cross-wave fluctuations.
Polesizer
An optical element that produces light with a certain state of polarization.
Analyzer
The optical part used to determine the direction of polarization of the light.
Double radius
Segregation of the beam in an anithropic environment into two beams with different refractation measures.
F
Origin and conclusion of the formulas
The fundamental law cannot be "proven" by algebras: for each record, it is stated whether it is a definition, an experimental law, or a model effect.
I
=
I
0
cos
⁡
2
α
I=I_0\cos^2\alpha
I
=
I
0
​
cos
2
α
empirical law
The law of the Malus.
The following is an indication of the definition, experience or law from which this entry arises and where it is applicable.
E
∥
=
E
0
cos
⁡
α
E_{\parallel}=E_0\cos\alpha
E
∥
​
=
E
0
​
cos
α
The analyser shall transmit the projection of the electric vector of the linear polarized wave on its axis.
I
∝
E
2
I\propto E^2
I
∝
E
2
The intensity of the electromagnetic wave is proportional to the square of the amplitude of the electric field.
I
=
I
0
cos
⁡
2
α
I=I_0\cos^2\alpha
I
=
I
0
​
cos
2
α
The quadrupling of the amplitude projection gives Malus the law, supported by experience.
Conditions:
The ideal linear analyser and fully linear polarized light; α is the angle between the polarization direction and the analyzer axis.
Monitoring:
The dimensions of both parts shall coincide; the result shall be checked for sign, order and limit case.
I
=
I
ест
2
I=\frac{I_{\text{ест}}}{2}
I
=
2
I
eats.
​
​
model effect
After the first polarizer.
The following is an indication of the definition, experience or law from which this entry arises and where it is applicable.
I
(
α
)
=
I
ест
cos
⁡
2
α
I(\alpha)=I_{\text{ест}}\cos^2\alpha
I
(
α
)
=
I
eats.
​
cos
2
α
Natural light can be represented by a mixture of equally likely directions of linear polarization.
⟨
cos
⁡
2
α
⟩
0
π
=
1
2
\left\langle\cos^2\alpha\right\rangle_{0}^{\pi}=\frac12
⟨
cos
2
α
⟩
0
π
​
=
2
1
​
The average square of the projection in all directions is one second.
I
=
I
ест
⟨
cos
⁡
2
α
⟩
=
I
ест
2
I=I_{\text{ест}}\left\langle\cos^2\alpha\right\rangle=\frac{I_{\text{ест}}}{2}
I
=
I
eats.
​
⟨
cos
2
α
⟩
=
2
I
eats.
​
​
The perfect first polarizer misses half the intensity.
Conditions:
The uninsulated light falls on the ideal polarizer; no absorption above the selection of one polarization.
Monitoring:
The dimensions of both parts shall coincide; the result shall be checked for sign, order and limit case.
!
Model boundaries and typical errors
Error: Forget model condition
You can't put the formula on any situation just because it's a coincidence of letters. The key condition of this topic is that natural light is usually not polarized.
How to Check the Mind
The polarizer passes the field component along its axis. Then check the units, vector direction and the behaviour of the result at zero or very large parameter.
Σ
Conclusion on the topic
Polarization of light
Polarization describes the orientation of the fluctuations in the electric field; it proves the transverse nature of the light and is used to control the lights and contrasts.
Natural light is usually not polarized.
The polarizer passes the component field along its axis.
Any numerical result shall be accompanied by a unit, a sign and an explanation of its physical meaning.
The content is consistent with the FRP on Physics of the OS/OSS 2025 and the subject matter of the current lines of the PNP: I. M. Peryškin and co-authors (7–9), G. J. Mäkishev and coauthors (10–11), and with the lines "Engineers of the Future" and V. A. Kasyanov. The original texts are not reproduced, the text of the textbooks is not reproduced.