Advisor(s)

Prof. Yin-Jung Chang

Research

Key Areas

Nano Optics, Integrated Optics based on Surface Plasmon Polaritons, Nanostructured Optoelectronic Devices and Physics, Electromagnetic Problems in Photonics

---

Research Descriptions

Nano Optics

Nanoscale dielectric research

In nanophotonics, nanoscale dielectric materials are ubiquitous and have a direct impact on device functionality and performance. To be able to predict the performance accurately at nanometer-scale sizes in these structures, it is essential to know the optical properties of the constituent materials. In nanophotonic applications, dielectric materials play a central role. For particular device configurations, it may be necessary to have alternatively high index materials, low index materials, high birefringence materials, or low birefringence materials. For reliable and reproducible photonic structures, the index of refraction and the birefringence of these dielectrics must be controllable by design. Therefore, understanding the optical properties, in particular, the indices of refraction and the birefringence, of these nanoscale dielectrics is fundamentally important. This knowledge is needed, for example, to provide various indices of refraction and birefringences for the design of future nanophotonic integrated circuits.

By evaluating directly the summation of induced-dipole-electric-field contributions from all individual atoms within the entire dielectric volume, we theoretically predicted that the dielectric properties of the finite cubic crystal lattices change from isotropic to birefringent (uniaxial or biaxial) when the entire dielectric volume is changed from a cube to a rectangular parallelepiped in shape. In finite tetragonal crystals the birefringence increases with the increasing lattice constant ratios. The largest uniaxial birefringence occurs for non-cube dielectric volume with tetragonal lattices.

Integrated Optics based on Surface Plasmon Polaritons

High-index contrast dielectric waveguides have been in widespread use for many years as  they offer a strong mode confinement, dense integration, low propagation loss (if smooth sidewalls are attainable), and the ease of fabrication through mature semiconductor technologies. However, further downscaling waveguiding structures is hampered by the natural diffraction limit. Strong sub-wavelength field confinement thus becomes crucially important. Nanophotonics using surface plasmon polaritons (SPPs), also termed as plasmonics, has been attracting much renewed attention worldwide in the last decade and is now considered as a promising solution for the implementation of optical nanocircuitry. However, with the development of silicon-on-insulator technologies, plasmonic waveguides show marginal advantages over their dielectric-based counterparts in terms of the propagation loss and waveguide dimensions. In view of bringing light from long-haul optical networking into chip-scale photonic circuits by pushing the envelope of the current technologies, combining the advantages from both dielectric- and plasmonic-based structures, which may be complimentary to each other in nature, could pave the way toward high-performance, ultrahigh-density optical nanocircuitry in the future.

Plasmonic waveguide Bragg grating in metal/multi-insulator configuration

Plasmonic-Mode-Assisted Polarization Splitter

Plasmonic-Mode-Assisted Sharp Waveguide Bend

Nanostructured Optoelectronic Device and Physics

Solar Energy Conversion via Internal Photoemission in Aluminum, Copper, and Silver: Band structure Effects and Theoretical Estimates

 

 

Internal Photoemission for Photovoltaic Using p-Type Schottky Barrier: Band structure Dependence and Theoretical Efficiency Limits

 

 

---

Recent Projects

Facilities

Publications and Patents

Journal Papers
1 Y.-J. Chang*, K.-H. Shih, and C.-Y. Hsiao, “Photonic-plasmonic hot-electron-based photodetection with diffracted-order-resolved leaky plasmonic mechanisms,” Nanophoton., vol. 11, pp. 4439-4453, Aug. 2022. 2 Y.-J. Chang*, K.-H. Shih, and K. Muthuramalingam, “Aluminum-based concurrent photonic and plasmonic energy conversion driven by quasi-localized plasmon resonance,” Opt. Express, vol. 28, pp. 37669-37685, Dec. 2020. 3 K.-H. Shih and Y-J. Chang*, “Internal photoemission for photovoltaic using p-type Schottky barrier: Band structure dependence and theoretical efficiency limits,” J. Appl. Phys., vol. 123, p. 023107, Jan. 2018. 4 Y-J. Chang* and R.-W. Feng, “Hybrid plasmonic mode converter – Theoretical formulation and design with a graphical approach” Appl. Opt., vol. 56, pp. 5501-5510, Jul. 2017. 5 Y-J. Chang* and R.-W. Feng, “Embedded-Silicon-Strip-to-Hybrid-Plasmonic Waveguide Polarization Mode Converter” IEEE Photon. Technol. Lett., vol. 29, pp. 759-762, May 2017.

Courses Offered

Undergraduate Courses - Required

OS2003 Electromagnetics (I) (Fall 2018, Fall 2019)

OS2004 Electromagnetics (II) (Spring 2019, Spring 2020)

OS2010 Microelectronics Laboratory (Spring 2009, Spring 2010)

OS2011 Semiconductor Physics in Optoelectronics (Fall 2008 - Fall 2012)

OS3002 Introduction to Photonics (Spring 2014)

Undergraduate Courses - Optional

OS3016 Electromagnetics (III) (Fall 2020)

Graduate Courses

OS6023 Radiometry and Detection

OS6072 Semiconductor Optoelectronic Physics and Devices (Lectured in English)

OS7104 Integrated Optics (Lectured in English)

OS7160 Physical Foundations of Semiconductor Optoelectronics (Lectured in English)

OS7168 Electromagnetic Princples of Photonics (Lectured in English)

OSA020 Electromagnetics

Graduate-Level Special Topics

OS6060 Special Topics on Integrated Optics

OS7131 Special Topics on Electromagnetic Theory (Lectured in English)

OS7183 Speical Topics on Optoelectronic Physics and Devices

People Postdoctoral Fellows

None

---

Present Students

Ph.D. students:

None

MS students:

Fall 2018

Kuo-Hwa Lai

Kuo-Hwa is currently a section manager of MEMS & Photonic Engineering in ASE group.

- Research area: Plasmon-enhanced Si photodector with OE                          packaging considerations

Spring 2020

Kuan-Yu Hwang

- Research area: Hot-carrier-based NIR photodetection

Fall 2020

Jung-Jun Dong

- Research area:Hot-carrier-based NIR photodetection

Undergraduate students:

None

---

Former Students

Ph.D.:

None

MS:

2010

You-Chang Liu

Thesis: A 90-degree Waveguide Bend in Metal/Multi-Insulator Configuration for Silicon-Based Optical Nanocircuitry

Guo-Yuan Luo

Thesis: A Novel Metal/Multi-Insulator/Metal Waveguide Plasmonic Bragg Grating

2011

Yu-Ting Chen

Thesis: Broadband Omnidirectional Antireflection  Coatings for Metal-Backed Solar Cells Optimized Using  Simulated Annealing Algorithm Incorporated with Solar Spectrum

Wei-Lung Li

Thesis:Directional-Coupler-Based Polarization Splitting  in Asymmetric Metal/Multi-Insulator Configuration for  Optical Nanocircuitry

2012

Chun-Yu Chen

Thesis: Higher-Order-Mode-Synthesized Waveguide Plasmonic Bragg gratings Using Semi-Analytical Approach

2013

Tsung-Han Hsieh

Thesis: Design and Analysis of Plasmonic Waveguide  Bends Using Conformal Mapping Incorporated with  Transmission-Line Network Approach: Comparisons with Numerical Results.

Chiao-Wei Hsu

Thesis: Resonant Coupling of TE Wave Incidence to  Asymmetric Metal-Dielectric Multilayered Structures at  Optical Frequencies.

Chi-Sheng Lai

Thesis: Investigation of Lossy-Film-Induced Optical  Effects for Maximum Transmittance into Absorption  Layers of Thin-Film Solar Cells.

2014

Yu-Huan Chen

Thesis: On the Radiatoin-Mode Enabled Resonant      Optical Tunneling in Asymmetric, Single Barrier    Potential System with Metal

2015

Tsung-Hsien Yu

Thesis: Photonic-to-Hybrid Plasmonic Polarization Mode Converter

2016

Ko-Han Shih

Thesis: Theoretical Investigations of Solar Energy Conversion
Based on Internal Photoemission in Metals

Karthicraj Muthuramalingam

Thesis: Polarization-Insensitive Two-Dimensional Periodic Metallic Absorbers in Structured Metal-Insulator-Metal Configuration for Plasmon-Enhanced Photoelectric Conversion

Ren-Wei Feng

Thesis: Mode-Evolution-Based Embedded Si Strip-to-Hybrid-Plasmonic Waveguide Polarization Mode Converter

2017

Kuo-Yu Lee

Thesis: Standard-CMOS-Process-Based Avalanche Photodiodes with T-shaped Polysilicon Gratings

2019

Chun-Yu Hsiao

Thesis: Hot-Electron-Based, Coupled-Plasmon-Enhanced Plasmonic Photodetector at Visible Frequencies

Bachelor:

Chun-Yu Chen (2010), Hong Chen (2011), Chi-Sheng Lai (2012), Tsung-Tsien Yu (2014), Ko-Han Shih (2014), Wen-Yen Chiu (2014), Da-Qing Zi (2014)

Research Opportunities

We constantly look for M.S. and Ph.D. students who are

• interested in electromagnetics, semiconductor physics, or solid state physics,
• not afraid of engineering math or mathematical methods for physics,
• self-motivated, patient, dare to explore things having no standard answers, and not getting frustrated easily.

If you appreciate having weekly/biweekly one-on-one meeting with Prof. Chang and believe this may be of any help to you, you are the one who shall enjoy your study/research in this group.So please contact Prof. Chang for more details.

Lab Activities

Lab gathering (1), Spring 2011		Lab gathering (2), Spring 2011		Chi-Sheng and Yu-Huan, Kenting National Park, Summer 2012