Proposal for Being a KAGRA Member
July 30, 2012
Kyuman Cho
Department of Physics, Sogang University
OVERVIEW
I.
Introduction
− Sogang University
− Photonics Lab
II.
Recent Researches on Interferometry
III. Research Plan
I. Introduction
Seoul
Sogang U.
City Hall
Han River
Yonsei Univ.
Ewha Womans Univ.
Shinchon (新村) Area
Hongik Univ.
Sogang Univ.
Overview
History
Established in 1960 by American Jesuits
Faculty: 402 Full-time, tenure-track faculty members
Students
Undergraduate: 8,000
Graduate: 4,000
Over 1,000 international students
Many courses taught in English
Ranked #1 in National Customer Satisfaction Index survey
in 1998, 1999, 2003, 2004, 2006
Ranked #1 in Korean Standards-Service Quality Index
survey in 2007, 2009, 2010
Academic Program
School of Humanities
School of Social Sciences
School of Natural Sciences
Mathematics
Physics
Chemistry
Life Science
School of Engineering
School of Economics
School of Business Administration
School of Communication
College of Natural Sciences
Department of Physics
17 Professors
Particle Physics
Condensed Matter Physics
Optics
BK21 Project
World Class University Project
Center for Quantum SpaceTime
Center for Quantum Chaos Applications
http://physics.sogang.ac.kr
Researches in Photonics Lab
Interferometry
High-resolution scanning optical microscope
High sensitivity readout sensors for biochips and micro-fluidic channels
Measurement of magnetic birefringence in vacuum
Precision sensor for measuring displacement, current, magnetic field, etc.
BES for plasma diagnostics
NSOM, etc
Physical, Chemical,
Biological Phenomena
Linear and
Non-Linear
Optics
Modulation
(Phase, Frequency
Amplitude, Intensity)
Data, Information
Contents, etc.
Sensors
Transmission Line
Fiber & FSO
Optical
Communications
Measurements
of Optical
Parameters
Demodulation
(Phase, Frequency
Amplitude, Intensity)
Data Recovery
FSO communications for subscriber service (fixed & moving)
Visible light communications
Members and Collaborators
Current Members
Post Doctoral Fellow: Dr. Youngkyu Park
Ph.D. Students:
−
Seung Hyun Yoon
−
Seang Hor Eang
−
Joonkyu Park
Undergraduate Intern: Yongjae Kim
International Collaborators
Prof. Christopher C. Davis, University of Maryland, USA
Prof. Anatoly Zayatts, Kings College, UK
Dr. Igor Smolyaninov, BAE System, USA
Domestic Collaborators from
Universities: Korea Univ., Postech, Yonsei Univ., Ewha Univ., etc.
Research Institutions: ETRI, KIST, KETI, etc.
Industries: POSCO, GSI, NanoStorage, KAC, etc.
Recent Researches on
Interferometry
Research Subjects
One of the pioneers in the homodyne and heterodyne
I/Q-interferometer: The 1st version of the homodyne and
heterodyne I/Q-interferometer was developed in 1994
and 1995, respectively.
Have been designing and optimizing homodyne and
heterodyne I/Q-interferometers for various applications:
Scanning interferometer
biosensors,
vibrometer,
and the other high sensitivity and wide dynamic range
measurements in both academic and industrial applications
Have been working on feasibility study for measuring
magnetically induced birefringence in vacuum:
A balanced homodyne scheme was proposed in 1991.
Improved version of the MIBD was submitted to NSF and KRF in
2010 and 2012, respectively. Still looking for a proper funding.
Optical I/Q-Demodulator
ES e  i (t S )
BS or PBS
HWP PBS1
ELO e  i (t LO )
QWP
HWP
PBS2
Can measure amplitude and
phase change of the probe
beam simultaneously
No need for feedback control
to maintain optimum
sensitivity
Application Example
Scanning Interferometer for complex surface diagnostics
RF I/Q-Demodulator
Application Example
Scanning Interferometer for complex surface diagnostics
Application Example
Phase and amplitude images of a patterned surface
Application Example
Wide measurement range interferometer
An astigmatic position sensing scheme is integrated to
the heterodyne I/Q-interferometer.
The interference signal is used for high resolution
measurement while the astigmatic sensor is used for
wide range measurement.
Application Example
Scanning results (step height  3 μm)
Application Example
New arrangement using double pass in AOM
Application Example
Vibration Measurement
 The equivalent minimum displacement ~ 5 x 10-13 m
Application Example
Scanning microscopy
The topography (a), amplitude (b), and color-scaled amplitude (c)
Application Example
Readout sensor for a fluidic channel
In
Out
Application Example
Dual mode
Dual mode
laser
laser
I
BS : Beam splitter
PBS : Polarization Beam Splitter
POL : Polarizer
M : Mirror
HWP : Half Wave Plate
QWP : Quarter Wave Plate
PD : Photo Diode
PZT : Piezoelectric Transducer
OI : Optical isolator
OL : Objective Lense
Q
OL
OL
Sample
K. H.Constant-Phase
Kwon, B. S. Kim, Scanning
and K. Cho,Heterodyne
OPTICS EXPRESS,
16, 13456 (2008)
Interferometer
Application Example
Scanning Results
(a), (c) : constant-phase scheme, (b), (d): conventional scheme
 The proposed microscope can measure both amplitude and phase simultaneously.
 The reflectivity image of the constant-phase scanning microscope is more clear
than that of the HIQI.
Proposed Scheme for Measuring MILB
Magnet
FR(F)
M2
Laser
FR(-F)
PBS
PD1
B
OI
Pol
CP
M1
QWP
DA
PD2
A
A
Current
Source
Two Faraday rotators are used to rotate the modulation principal axes.
This scheme can provide the same modulation effects as rotating the
magnet.
The modulation frequency can go up to tens of Hz which is high
enough to minimize 1/f-noise.
No possible artifacts can be expected at the measurement frequency.
Application Example
Proposed scheme for measuring MIB
Research Plan
Advanced Lab for GWD
Will do our best to get a proper research grant
A big grant proposal has been submitted.
Keep looking for grant opportunities if it is not awarded.
Will concentrate on the researches on GWD.
Perform extensive researches on GWD
Create new ideas for improving the sensitivity of the GWD
Establish a lab for building a prototype interferometer.
Gaining experiences on the large scale interferometer.
Testing new ideas for the GWD
Establish active research network with KAGRA members
Arrange regular meetings. (Ex: Prof. Shiniji Miyoki’s visit)
Exchange knowledge, ideas, and members.
Suggested KAGRA Collaboration Members
Prof. Christopher C. Davis, Dept. of ECE, Univ. of MD.
Mentor of the Photonics Lab.
Tens of years of experiences on interferometry, sensors, and
optical communications
Collaborator for designing interferometric measurement scheme
for MIB.
Dr. Youngkyu Park, Dept. of Phys., Sogang University
Ph.D. Students in Dept. of Phys., Sogang Univ.
Seung Hyun Yoon
Seang Hor Eang
Joonkyu Park