Here I will go through basic ophthalmology knowledge related to OCT application.

Fundus Image

The fovea and the optic disk are two distinct structures within the retina, each serving different roles in the process of vision.

1. Fovea: The fovea, or fovea centralis, is a small depression in the retina where visual acuity is highest. It is located in the center of the macula, an area of the retina responsible for high-resolution, color vision. The fovea is densely packed with cone photoreceptor cells, which are responsible for detecting light and color. Due to this high concentration of cones, the fovea is the point of sharpest vision, enabling activities that require detailed vision like reading, driving, and recognizing faces.

2. Optic Disk: The optic disk, also known as the optic nerve head, is the point in the retina where the optic nerve fibers exit the eye to transmit visual information to the brain. Unlike the fovea, the optic disk contains no photoreceptor cells, making it a blind spot in the field of vision. The optic disk is where the blood vessels that supply the retina enter and exit the eye.

Tomography Structures

I have to regularly organize and polish my thoughts about optical systems and fundamental theories. Put them here. Also, as a note for guiding freshmen.

— Longqian :)

现代神经生物学 Modern Neurobiology

Notes on Modern Neurobiology. Reference: Principles of Neurobiology. Liqun Luo.

This first version draft will be polished.

Quantum-Mechanics-Notes

Notes for quantum mechanics of MIT-OCW 8.04.

• Quantum Physics I: https://ocw.mit.edu/courses/8-04-quantum-physics-i-spring-2016/

’This is the goal of 8.04: we will step beyond the scale of daily experiences to develop an intuition for electrons, atoms, and superposition.’

线性代数学习笔记

Notes for Advanced Linear Algebra (Theorems and Proofs).

Textbook: Linear Algebra Done Right.

数理方法 Methods in Mathematical Physics

一 数学物理定解问题

1.1 定解问题的导出

（1）振动方程

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电动力学笔记 Notes on Electrodynamics

Electrostatics is the study of the Laplace equation. Electrodynamics adds the time-varying fields that are much more interesting and satisfy a wave equation.

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Fundamentals of Ultrasonics

1 Introduction

• 1883, Galton devised a high-frequency whistle to measure the upper frequency limit of response of the human ear
• 1914–1918 war, Langevin, underwater soundings
• 1925, Pierce, quartz-driven ultrasounic interferometer
  • Pierce: observations of velocity dispersion in carbon dioxide
• 1932, Debye and Sears and Lucas and Biquard, ultrasonic diffraction grating
• 1934, Sokolov, ultrasonic flaw detection
• 1939–1945 war, pulse technique

2 General Principles of Propagation of Low Amplitude Waves

Free vibrations

• compression waves and shear waves

• compliance of a spring : inverse of spring constant

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• For small damping the frictional force is proportional to the velocity:

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  • Physics and math behind this:

    

  • interesting property:

    

• Energy: kinetic and potential energy

  

  • remains constant at all times in the abscence of damping.

  • Fractional loss per cycle :

    

• Forced vibrations and LRC circuit

  • solving the differential equation: 1) homogeneous part by inputing ; 2) non-homogeneous part by putting into a particular solution according to the forcing term or .

The velocity of plane waves

General plane wave: that satisfies the wave equation.

simple harmonic vibrations: (Re. ?)

Young’s modulus: pressure per strain

Hooke’s law (pressure ~ modulus of elasticity and displacement chaneg rate):

Condensation (change of the density):

Reading List

• https://coilab.caltech.edu/research/compressed-ultrafast-photography-cup

Streak Camera

• https://www.hamamatsu.com.cn/cn/zh-cn/product/photometry-systems/streak-camera/operating-principle.html

Project in modern optical testing course.

It takes me half day to read and understand the laser-ranging, and one whole day to design, simulate, and write the project report.