Download Prelims 2016 Prof. Candler 1) Have student explain his/her research

Prelims 2016 Prof. Candler
1) Have student explain his/her research area and background. Ask questions based on
this.
2) Show your tuning fork resonator. It rings at some frequency, f, described by
𝑥 = 𝑥! 𝑒 !!!"# . Exactly how would you expect the resonant frequency to change as you
scaled the device down? Perform same analysis for LC resonator and compare the two,
focusing on fundamental similarities of these two systems
PhD Preliminary Examination 2016
Professor Frank Chang
PhD Preliminary Examination 2016
Professor Frank Chang
PhD Preliminary Examination
2016 Professor Frank Chang
Prof. Iyer
2016 Prelim Exam Questions:
1. Fig 1 below shows a tiled view of Samsung’s FINFET process in 14 nm
’
Let’s discuss this picture.
a.
b.
c.
d.
e.
f.
g.
h.
Can you point out where the fin is its direction?
Where are the source-drain contacts?
Where are the gate contacts?
Is the FINFET a symmetric device?
Can you say something about the gate material?
Can you draw a model for the FINFET?
Why is the FINFET an “ideal device”?
What are the key drawbacks of the FINFET?
2016 PhD Preliminary Exam
Prof. Joshi
Set A
1.
2.
3.
4.
What is a plane wave?
What do we mean by a beat wave?
What do we mean by an amplitude modulated waveform?
What is the frequency spectrum of the waveform?
Set B
1. Write electric field of a laser that is Gaussian in time.
2. What does the frequency spectrum of this pulse look like?
3. How do you produce a “chirped” pulse?
Set C
1. What is the physical origin of permittivity and permeability?
2. If we had hydrogen gas, water vapor, and CO2 gas and applied an electric field, what would
be the order of polarization produced in each?
Set D
1. What is a plane em wave?
2. What do we mean by amplitude modulated wave?
3. Does amplitude modulation cause frequency broadening?
2016 Ph.D. Prelim Questions
J.M. Liu
Your Name:
Questions:
1. Among the four fields E , D , B , and H of an electromagnetic wave, which ones
are always perpendicular to the wavevector k in any medium and in any spectral
region? For each field that is not always perpendicular to k , discuss the situations
when it can be perpendicular to k and give a situation when it is not perpendicular
to k . Explain briefly.
2. What are the conditions for laser oscillation? Describe the essential requirements that
you must meet to construct a working laser oscillator. What changes in its
characteristics do you expect to see when a laser starts to oscillate above threshold?
3. Silicon is the most important electronic material, but it has limitations in photonic
applications. Describe and explain the possibilities or limitations of using silicon to
construct a Pockels cell, a Faraday rotator, an acousto-optic modulator, an LED, a
laser, or a photodetector.
PhD Preliminary Examination 2016
Professor Ozcan
PhD Preliminary Examination 2016
Professor Rahmat-Samii
PhD Preliminary Examination 2016
Professor K. Wang
Preliminary Exam 2016
Professor Y. Ethan Wang
Derive the Quality factor of a quarter waves transmission line resonator that has a characteristic
impedance Z0, loaded with a resistor R (R<<Z0).
PhD Preliminary Examination 2016
Professor Williams
Prelims 2016
Professor Williams
What is the Quality Factor Q? Give an example.
Estimate the quality factor of a cavity mode of a Fabry-Perot optical cavity (air/dielectric/air). The
thickness of the dielectric slab is 0.5 mm, the index of refraction is n=9, the wavelength of light is 1μm.
PhD Preliminary Examination 2016
Professor Woo
PhD Preliminary Examination 2016
Professor Woo
PhD Preliminary Examination 2016
Professor Woo