# PHYC30080 Optics & Lasers

This module addresses fundamentals of optics and lasers in four themes:
Theme 1. Background, refraction & reflection;
Theme 2. Rays and Lasers, a unified approach;
Theme 3. The Fourier transform in optics and lasers;
Theme 4. Coherence and spectroscopy.

These topics interconnect and build on each other. Weekly assigned homework and assessed worksheets address problems in sync with lectures.

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Curricular information is subject to change

Learning Outcomes:

You will acquire a fundamental and interconnected understanding of geometric and laser optics, Fourier methods and spectroscopy. By nature of being fundamental physics, this is broadly applicable across industries and science.

Indicative Module Content:

1. Background and ray optics.
A background is given on complex numbers, waves and rays. We consider refraction, reflection, lenses and imaging using rays.

2. Rays and Lasers, a unified approach.
We unite geometric optics with diffractive laser optic. Using a straight forward but powerful matrix tool, we investigate the behaviour of lenses and lens systems and we explore the idea of principal planes. We then apply the same methods to predict the behavioiur of lasers beams and primary properties of laser cavities. We also discuss geometric aberrations.

3. The Fourier transform in optics and lasers.
We introduce the complex Fourier transform and relate it to the optics of free propagation, a single lens and a telescope. We explore the scaling theorem, delta functions, a spatial or temporal displacement relating to a Fourier linear phase and visa-versa. We develop a Fourier understanding of interference from experiments such as Young's slits and diffraction gratings, and we consider diffraction from hard and soft apertures. We go on to derive and use the convolution theorem in one and two dimensions and the associated OTF, PSF and MTF. We consider applications of convolution, for example to understand fluorescence and the temporal output of a pulsed laser. Finally, we consider dispersion, group and phase velocity.

4. Coherence and spectroscopy.
We explore coherence and visibility in spectroscopy using our learning from themes 2 and 3. We arrive at criteria for observation such as rayleigh, Strehl and Sparrow, resolving power and finesse. We consider the Fresnel zone plate and the effects of a partial degree of coherence.

Student Effort Hours:
Student Effort Type Hours
Specified Learning Activities

44

Autonomous Student Learning

44

Lectures

22

Small Group

10

Total

120

Approaches to Teaching and Learning:
We blend in-class and online learning. Assessment and feedback is synchronised weekly with the delivery of our module materials. You are assigned a worksheet (WS) each week in relation to that week's materials. Later in the weekly cycle you submit your solutions. Your worksheet is returned to you graded in the subsequent session with Q&A focused to addressing your questions on that worksheet, and we introduce your next worksheet.

Physics isn't best learnt by rote, or in an ivory tower. Rather it is learnt from independent struggles with problems, whilst pulling on materials and discussion. We hold an assessed session of Q&A weekly, in which we address any questions you have in sync with the module delivery, with a focus to HW. Forming good questions is core to science because asking the right question is halfway to a useful answer. Grades are awarded to students that raise the best Q’s (rated on your physical insight and the benefit to class learning), or that engage in discussions most helpful for class learning. To benefit most from this Q&A, you will be doing all your assigned HW in sync with the module delivery.

Requirements, Exclusions and Recommendations
Learning Requirements:

Irish/UK/US introductory-level maths for university engineering/physics, or equivalent level, to include: algebra, geometry, trigonometry, integral and differential calculus of algebraic and trigonometric functions including up to second-order differential equations

Learning Recommendations:

PHYC 20010

Module Requisites and Incompatibles
Not applicable to this module.

Assessment Strategy
Description Timing Open Book Exam Component Scale Must Pass Component % of Final Grade In Module Component Repeat Offered
Continuous Assessment: Homework Throughout the Trimester n/a Graded No

40

No
Examination: Examination 2 hour End of Trimester Exam No Graded No

60

No

Carry forward of passed components
No

Resit In Terminal Exam
Summer Yes - 2 Hour