Quantum Optoelectronics Devices
| Numbering Code | G-ENG11 5C828 LJ72 | Year/Term | 2022 ・ Second semester | |
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| Number of Credits | 2 | Course Type | Lecture | |
| Target Year | Target Student | |||
| Language | Japanese | Day/Period | Tue.4 | |
| Instructor name |
NODA SUSUMU (Graduate School of Engineering Professor) ASANO TAKASHI (Graduate School of Engineering Associate Professor) |
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| Outline and Purpose of the Course | This course explains a method for systematic analysis of the interaction between light and electrons, and how to control the interaction. First, we explain the density matrix as a method to treat the time evolution of a quantum system including the relaxation process due to the interaction with the external environment. In addition to calculating the optical response of a simplified electronic system and determining the optical absorption coefficient and gain, we show how to calculate the second harmonic generation and two-photon absorption. Next, we explain the band structure and density of states of the electron system in a semiconductor as a more realistic model, and explain that the absorption coefficient and gain can be controlled by controlling the quantum structure such as quantum wells. Furthermore, we will show that it is possible to control the interaction between light and electrons by controlling the photon system with microcavities, etc., and that it is possible to enhance the spontaneous emission rate and form electron-photon strong coupling states. | |||
| Course Goals | Students will learn how to calculate the optical absorption coefficient/gain and refractive index in quantum structures. Students also will understand the interaction between light and electrons, including nonlinear response. Students will understand how to control spontaneous emission. | |||
| Schedule and Contents |
1. Introduction (1 time) The academic background of optical quantum device engineering is described. 2-1. Methods for analyzing electron-photon interactions (4 times) After reviewing the basics of quantum mechanics, we discuss the interaction of light with two-level electron systems. We will discuss the necessity and derivation of density matrix theory, and show that it can represent both pure and mixed states. We also explain the difference between energy relaxation and pure phase relaxation in terms of the relaxation processes that can occur due to the interaction with the external environment, by deriving them from physical models. In this way, we derive a method to describe the time evolution of a quantum system including the relaxation process using a density matrix. 2-2. Optical response of simplified electron systems (4 times) We explain how to derive the steady-state response of the density matrix describing the interaction between a two-level electron system and classical continuous wave light. We show how to calculate the complex permittivity, the absorption (gain) coefficient, and the change in refractive index from the linear response to the incident electric field. The higher-order responses to the incident optical field are also discussed, and the absorption and gain saturation are explained. Then, the electronic system is extended to three levels, and the principle and calculation method of optical nonlinear responses such as second harmonic generation, difference frequency generation, electro-optic effect, and two-photon absorption, which can occur only in electron systems with more than three levels, are explained. 3. Control of electronic systems and interaction of electrons and light (2.5 times) The interaction between electrons and light in semiconductor quantum wells are explained. First, the band structure of bulk semiconductors and quantum wells are explained. Then, the calculation method of the complex permittivity by integration considering the density of states is described. After discussing the absorption spectra and polarization properties of the inter-subband transitions, the absorption spectra and polarization properties of the inter-band transitions are discussed. 4. Control of photons and electron-photon interaction (2.5 times) We discuss control of spontaneous emission of light based on the control of photon states. First of all, the photonic system is described as a quantum state, and the system is treated as composite system of an interacting electron and photonic system, where its time evolution is described using a density matrix. Then, we derive the spontaneous emission rate of a two-level electron system in free space. Next, we discuss the enhancement of the spontaneous emission rate when a two-level electron system interacts with a single mode of a microcavity. We also discuss the physics of the strongly coupled electron-photon system. 5. Confirmation of learning achievement (1 time) Confirmation of learning achievement |
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| Evaluation Methods and Policy | Evaluations are made on the basis of reports. | |||
| Course Requirements | None | |||
| Study outside of Class (preparation and review) | Nothing of note. | |||
| Textbooks | Textbooks/References |
The lecture notes format is used in this course. Other reference materials may be distributed and discussed as necessary. |
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| References, etc. | Laser Physics, Murray Sargent III, Marlan O. Scully, Willis E. Lamb, Jr. , (Westview Press), ISBN: 9780201069037 | |||
| Related URL | ||||
