of 38
8/3/2019 Laser Masroor
1/38
Light: Its Applications in interometery, polarimetry and photodynamic therapy
Masroor IkramMay 13, 2010
Pakistan Institute of Engineering and Applied Sciences
8/3/2019 Laser Masroor
2/38
Light ? By the end of nineteenth century wave nature of
light was well accepted and there was a slogan thatall the problems related to optics have been solvedexcept to prove ether.
In 1887 well-known Michelson-Morley experimentdisprove the concept of ether.
Earlier black-body radiation and in 1905 the famouspaper of photoelectric effect forced scientists torethink particle nature of light.
Since then light is considered to has dual nature.
8/3/2019 Laser Masroor
3/38
Light is an elephant An old story tells of three blind men who were
asked to describe an elephant. One blind man touched the elephants tail and
said the elephant was long and thin like a rope.
The second blind man touched the elephants legand described the elephant as round and hard likea tree trunk.
The third man felt an ear and said that theelephant was thin and flat, like a huge leaf.Each mans description was correct, but didntgive the complete picture.
8/3/2019 Laser Masroor
4/38
Scientists who study the nature of light are like theblind men in the story. They try to describe light, buttheir descriptions depend very much on which
aspects of light they study. Each description of light is merely an approximation
to the reality that is light. During the last fourcenturies, light is sometimes considered as particleand sometimes as wave, now scientists agreed on itsdual nature.
8/3/2019 Laser Masroor
5/38
Einstein in Optics and Lasers
Einstein is famous for relativity but hiscontributions in optics and lasers are alsofundamental.
In 1905, photoelectric effect shaken the basicsof the theory of light and Einstein was awardedNobel prize for it.
In 1916-17, he published two papers describingthe stimulated emission, which wasexperimentally demonstrated in MASER during1950s and led the foundations of LASER.
8/3/2019 Laser Masroor
6/38
Interferometry
8/3/2019 Laser Masroor
7/38
Michelson Interferometer
The Michelson interferometeris the most commonconfiguration for opticalinterferometry. Theinterference pattern produceddepends on the pathdifference between the twobeams.
Michelson & Morley used this
interferometer for theirfamous experiment (1887) inwhich this interferometer wasused to disprove the conceptof ether.
8/3/2019 Laser Masroor
8/38
Novel Interferometersfor precision angle and axis of rotation measurements
M. Ikram and G. Hussain, Michelson interferometer for precision angle measurements ,Appl. Opt. 38(1) 113-120, 1999.
8/3/2019 Laser Masroor
9/38
CarouselInterferometer
G. Hussain and M. Ikram, Optimization of
linearity by use of a glass plate in carousel interferometers , Opt. Letts. 29(16) 1930-32, 2004.
8/3/2019 Laser Masroor
10/38
Angle andAxis of
RotationMeasurementG. Hussain and M. Ikram,
Optical Measurements of Angle and Axis of Rotation , Opt. Lett. 33 (21)2419-21, 2008.
G. Hussain and M. Ikram,Measurements of Angle and Axis of Rotation in a Carousel Interferometer: ADetailed Analysis , Appl.Opt. 49(6) 1025-1031, 2010.
8/3/2019 Laser Masroor
11/38
Vibration Detection with Lasers
A. Hussain, S. K. Ayazuddin, M. Ikram , A. A. Mudassar, A. A. Qureshi, and M. Iqbal, Remote
sensing for flow induced vibrations in PARR-1 core assembly , Nucl. Engg. Design 205 (3) 323-31, 2001.
Intensitymodulation of thelaser beamprofile due tovibration of theobjective isdemodulated togive theamplitude and
frequency of vibration.
8/3/2019 Laser Masroor
12/38
Optical Coherence Tomography
Optical Coherence Tomography (OCT)performs imaging by measuring the echotime delay and magnitude of back reflected
or backscattered light using interferometry. The most common detection method is
based upon a Michelson interferometer with
a scanning reference arm. In OCT low coherence light source is used,
e.g. Ti: Sapphire laser or SLDs
8/3/2019 Laser Masroor
13/38
OCT is capable of high temporal resolutionallowing the study of dynamic physiologicfeatures
Optical measurements can be performedexceedingly fast (
8/3/2019 Laser Masroor
14/38
Experimental Setup of OCT
8/3/2019 Laser Masroor
15/38
PolarimetryPolarization sensitive optical imaging
8/3/2019 Laser Masroor
16/38I' = M I
M = 4 x 4 Mueller Matrix
II'
Laser
M
IQUV
Total Intensity
I =
Scatterer, representedby Mueller matrix,
Incident beam
ScatteringAngle
ScatteredBeam
Circular Polarization 45 0,90Polarization
Polarization Imaging
8/3/2019 Laser Masroor
17/38
detector
sample cell
polarizer
Light source
plane isrotated analyzer
aaplane-polarizedlight
observedrotation
00000
rotate to null
A Simple Polarimeter
8/3/2019 Laser Masroor
18/38
Stokes Vector
+
==+
LCP RCP
V H
V H
I I
I I I I
I I
S
SS
S
s4545
3
2
1
0
8/3/2019 Laser Masroor
19/38
To determine the properties of emergingbeam, one multiplies the vectors describingthe incident beam with Mueller matrices. Ingeneral, the interaction of light with optical
elements such as lenses, polarizers, filters,surfaces, scattering media etc, changes thepolarization state of the light, when itdescribed by a four-component vector,[S 0 ,S 1,S 2 ,S 3 ], interacting with any opticalelement or material .
[S out ] = [ Msystem ].[S in]
Mueller Matrix
8/3/2019 Laser Masroor
20/38
Curve fits for the calculation of unknowncoefficients
Photo-detector
Polarizerat 45owith E
Analyzerat -45owith E
Melles GriotM/N 05-LHP-1115mW Max Output
= 632.8 nm
Plate
Lenses fordiverging the
light
Kerr CellL
dTerminalsfor Voltage
Ea Y axis
X axis
Z axis
Material characterization withpolarized laser light (Kerr Cell )
8/3/2019 Laser Masroor
21/38
0 1000 2000 3000 4000 5000 60000.0
0.2
0.4
0.6
0.8
1.0
Applied Voltage (V)
N o r m a l i z e d T r a n s m i t t a n c e
Solid curve is the simulated result of traditional expression for intensitytransmittance where as filled circles is the experimental transmittance for
Nitrobenzene device
8/3/2019 Laser Masroor
22/38
Depolarization of light from nitrobenzene
0 1000 2000 3000 4000 5000
0.0
0.2
0.4
0.6
0.8
1.0
= 45o, = -45 o
N o r m a l
i z e d
T r a n s m
i t t a n c e
Applied Voltage (volt)
= 45 o, = 45 o
= 0 , = 0
Curve fit for = 0
, = 0
= 0 , = 90
Curve fit for = 0 , = 90
Estimate of MaxI 45,45Curve fit for MaxI 45,45
Estimate of MinI 45,45Curve fit of MinI 45,45
S. Firdous, K. Hassan and M. Ikram , Applied Optics 44(7) 1171-77 (2005)
8/3/2019 Laser Masroor
23/38
Characterization Of UHMWPE UsingMueller Matrix Polarimetery
Using standard Mueller Matrix Polarimeter, it is trivial toobtain 16 elements of a Mueller matrix.
In order to get some physical information from Muellermatrix, the decomposition can provide information of material parameters.
In one of the decomposition algorithm (i.e. LU-Chipmandecomposition), Mueller matrix is decomposed intosequence of three matrix factors; a di-attenuator followedby a retarder and a depolarizer.
The three matrices gives the di-attenuation, polarizance,depolarization and retardence.
8/3/2019 Laser Masroor
24/38
Optical Biopsy
8/3/2019 Laser Masroor
25/38
Photodynamic TherapyCancer Treatment with Lasers
8/3/2019 Laser Masroor
26/38
Two individually non-toxic componentsbrought together to cause harmful effects oncells and tissues in the presence of oxygen
Photosensitizingagent
Light of specific
wavelength
Process of Photodynamic Therapy
8/3/2019 Laser Masroor
27/38
8/3/2019 Laser Masroor
28/38
Illustration of the Process
The photosensitiser is given by injection.
After time the photosensitiser concentrates in
the tumor.The photosensitiser isactivated by light
The tumor is selectivelydestroyed
Mechanism
Celulardestruction
8/3/2019 Laser Masroor
29/38
Epidermis
Basal cell carcinoma
5-AminolevulinicAcid
selectivetumor necrosis
Topical PDT
8/3/2019 Laser Masroor
30/38
In Vitro Studies of PDT on HeLa andHep2c Cell Lines
HeLa is a cell line of human cervical cancer,from a Mexican female Henrieta Lacks.
HeLa cells were grown with 5-ALAphotosensitizer in the laboratory of NationalInstitute of Health, Islamabad.
The primary focus of the experimental work
was to study he efficacy of ALA mediatedphotodynamic effects in HeLa cells.
8/3/2019 Laser Masroor
31/38
-20 0 20 40 60 80 100 120 140 160
20
40
60
80
100
120
% V i a b i l i t y
ALA Concentration (g/ml)
50 J/cm 2
0 J/cm 2
Comparison of Dark Cytotoxic & Phototoxic Effectsof different ALA Concentrations in HeLa Cell Line
M. Atif et.al. Laser Physics Letters 6 (12) 886-891, December 2009
8/3/2019 Laser Masroor
32/38
0 50 100 150 200 250
20
30
40
50
60
70
80
90
100
110
% V i a b i l i t y
ALA concentration, g/ml
85J/cm 2
0J/cm 2
Comparison of Dark Cytotoxic & Phototoxic Effectsof different ALA Concentrations in Hep2c Cell Line
A. Khurshid et.al. accepted in Laser Physics 20(7), pp--, July 2010
8/3/2019 Laser Masroor
33/38
Photodynamic Therapy: In Action
Profs. Hasan, Harvard Medical School and Georgakoudi,Tufts University, are observing the skin cancer treatmentperformed by Dr Rahmat Ullah Khan in NORI.
8/3/2019 Laser Masroor
34/38
After 72 hours
After 1 week
After 4 weeks
Aktinic Keratosis
Diagnosis:Basal cell carcinoma (Nose) andActinic Keratosis ( Left Cheek ).
Treatment:Two (02) sessions of PDT given .
Remarks:Gross tumor clearance with goodcosmetic outcome.
Histopathologicalclearance also seen onre-biopsy at 3 monthsfollow up in PIMS dated19-05-08 reported as Noevidence of malignancyfound.
34
8/3/2019 Laser Masroor
35/38
After 4 weeks
35
B f T t tAQ , 53 years male , resident of Peshawar
8/3/2019 Laser Masroor
36/38
Before Treatment
After Treatment...72 hours After 4 weeks
Diagnosis:Basal Cell Carcinoma ( left eye medial
canthus )Treatment :
Excision Biopsy doneTwo sessions of PDT given for positive
marginsRemarks:
09 months recurrence free periodwith good
cosmetic outcome.Histopathological clearance also seen
on re-biopsyat 9 months follow up in Peshawar
dated 27-11-08
reported as No evidence ofmalignancy found .
36
8/3/2019 Laser Masroor
37/38
Summary of PDT In vitro studies on HeLa and Hep2c cell line are
carried out and published. Clinically 28 biopsy proven skin patients are treated
in PAEC Hospitals. One patient of Leishmaniaisis is
treated with positive response. Follow up shows complete response for majority of
the patients and partial response for a few and onehas no response.
Currently we have treated only superficial skincancers but planned to start for internal cancersusing inject able photosensitizer and endoscope.
8/3/2019 Laser Masroor
38/38
I am Thankful to: Prof. Tayyab Hasan, Harvard University, Boston, USA
Prof. Vanderlei Bagnato, University of Sao Paulo, Brazil Dr Shamaraz Firdous, NILOP Dr Rahmat Ullah Khan, PAEC General Hospital Dr Muhammad Atif, NILOP
Hafeez Ullah, PIEAS
Malik Sajjad Mehmood, PIEAS Manzoor Ahmad, PIEAS Ahmat Khurshid, PIEAS Fakhar-e-Alam, PIEAS Muhammad Imran, PIEAS Lubna Noreen, NILOP Dr Sohail Zaidi, NIH , etc.
For Their Contributions