NIUSA

INSTRUCTION MANUAL FOR

POLARIZATIONOFLIMALUS
GHT LAWAND VERIFICATIONOF

bGAW
INDUSTRIGomplE-AmeaysxjPRODUCTS
Box No. 42,
:+91-171-2699212,9w
,2699213,
:+91-171-2699102.2699222, adkari PVT, LTD,
Road, Ansbaia
2699:699267, 2699757
agar@indosaw.com, Ganti33001 (ndia)
deducation@indnsaus noo
 INEES!
PRINCIPLEA
Linearrpolarized light
throughofathepolarlzatlon
passesposition
asafunction of the.angular
flter. Transmitted light intensity is determined
polarlzation filter.
OBJECTIVE:
1.
he plane of polaizätion of a linear,polarized laser beam is to be determined.
2. The intensity of the light transmitted by the polarization filter is to be determined as a
Yunction of the angular position of the filter.
3. Malus' law must be verified.
.CONTENT SPECIFICATIONS
Laser, He-Ne2.0 mW, y20 VAC 01

Optical bench Hexagonal, I 1 m 01

Transversal Saddle 01
Fixed Saddle 03

Polarizer / Analyzer 02
-Photo detector 01

Digital multimeter 01

Plug in lead red &Black Im 02

THEORY
Lightis a. tränsverse wave: We definethé direction öf polarization by the direction of the electric,
field vector E. Light from common sources such, as light bulbs is un-polarized or Laser source
.Linearly polarized, meaning that the plaDe of vibraton of the electric field 'vector changes its
orientation very rapidly and in a completely random fashion. However, when light interacts with
matter, that the plane of vibration of the electric field may become fixed in a particular direction
(inear polarization) or thát the plane of vibration rotate or otherwise vary in auniform (circular or
elliptical polarization).
Let's evaluate how.much ligh: is transmitted whèn
the transmission axis of a Pobroid is at an angle to polariser analyser
.the plane-of polarization. The two cases, what would
happen. if the transmissioF -axis is parallel or
perpendicular to the polariation direction of the
beam?. In the former cast all of the light is
transmitted, in the latter casenone of it is. In figure
1shows yhat happens whenthe transmission axis Figure 1
of Polaroid makes an angle with the plane of
"olartzetion of an incident bem. In igure 1an-ün-polarised beam of light is pd<arised by passing it
through a Polarold. The polaised beam is then passed through asecond Pulardid, often called the
analyser. The transmission a:is of the analyser makes an angle 0with the planelof polarisation of
the incident bam. The bean that emerges from the analyser is polarised in the same direction as
the transrnission axis of the aalyser.
 NDIOSA!
EVALUATION:

Let AA' be the Polarlzation planes of the analyzer In Fig. % A

If linearly polarized Iight, the vibrating plane of whichforms
an angle with the polarization plane of the filter,
impinges on the analyzer; only the part will be transmittd Rtu
EA =E cas &

As the intensity Iof the light wave is proportional to the E-E, cos
square of electric field intensity vector E, the following
relation (Malus' law) is obtained
A'
Figure 2

Multietex,e

Experimental setups
DESCRIPTIONS:
7.
1. Optical Bench, 2.Transversal saddle,3.Fixed Saddle, 4. He-N Laser, 5. Polariser, 6. Analyser,
Photocell, 8. Digital multimeter.
SET-UP ANDPROCEDrRS
polariser at
1. The experiment is set up according to above Figure asHe-Ne Laser at Ocm,
SOcm, Analyser at 75 Cn andphotocell at 125cm.
Note: Please mount the photocell in transversal saddie for adfustment.
Coninect the photocell to digital multineter and set its In 2000 4Amp Range.
 INEOSAH
3 Now switch ON the laser and adjust the height for He-Ne Laser, Polarlser, analyser and
photocell at same level.
the center.
4 Now move the photocell with transversal saddle for total illumination at
background current
5. l,the experiment is carried out in'a non darkened room,the disturbing
taken into accournt during
lo must, be- determined with the laser switched off and this must be
evaluation.
prevent disturbing
6 The laser should be allowed to warm up for about 30 minutes to
intensity fluctuations.
polariser such that no laser ight fall ori
Keep the analyser at 90° positions, then rotated the
the photocell.
between the polariser and analyser by rotating
8. Now take the reading (Amp) in steps of 10°
the analyser filter form +90° to -90
nAmp reading must be in fluctuation condition- because the laser beam intensity not
Note: both minimsm and maximum value for
rermajns constant. Therefore take the Yeading for
Amp.
OBSERVATION TABLE:
Jendalie adire.
Intensity (max) (Ho) (Ho/Urmax-lo)
Cos?0, Intensity in)
| Angie (0) 0.000
"90 0.000 0.029
10,1 8
:-80 0,030 6.) 32 '0,114
23 32
-70 71.5 0.256
53 90 71.5
-60 0.250 111 111 0397
86 136
'-50 0,413 145 145 0.519
117 173
-45 0.500 168 168 0.601
143 193
-40 0:587 203.5 "203.5 0.728
193 214
-30 0.750 .231.5 231.5 0.828
223 240
-20 0.883 270.5 -0.968
235 306 270.5:
-10 0.970 279.5 1.000
314 279.5
1.000 245 0.968
270.5 270.5
198 343 0.907
10 -0.970 253.5
182 325 253.5
20 0.883 210.5 0.753
266 210.5
30 ^o.750o -155 168 0.601
203 168
133 0.526
40 0.587 147 147
120 174
0.500 115.5 0.413
45 132 115.5
0.413 99 0.274
50 76.5 76.5
72 81 0.123
60 0.250 36 34.31 34.5
33 0.029
70 0,117
7 0.000
80 q:030
0.000 0
90
 NELSAW

300

Auto F for Deta Sel| Intensity

=A'exp--B2C^2)}--D
A: J17.3 8.299
j B: 0.6230 0.3733
G-58.74 1,486
D: -37.14 +-6.884
RMSE: 5.951
200
krsuguI

100
50
-100
(54.72, 325.9) Angle (0)
ofthà angular position 0 of the polarization plane of
Corrected photo cell current as a function
theanalyzer.
1.5

Unoer F foc Data Bot |(Holma-to)

(o-x8u)o-) SlopeA
b 0.8987006147
iRMSE: 0.01807

0.54

1.5
(0.4352, 1.2132) Cos2e

0
Normalized photo cell current as a function of cos²