PH3101 Physics Laboratory 1

Further information on which modules are specific to your programme.

Module description

The aims of the module are (i) to familiarise students with a wide variety of experimental techniques and equipment, and (ii) to instill an appreciation of the significance of experiments and their results. The module consists of sub-modules on subjects such as solid-state physics, quantum physics, lasers, interfacing, and signal processing and related topics.

Additional information from school

Overview

This experimental laboratory-based module is made up of a set of sub-modules, with students undertaking five sub-modules in the course of the semester. Each sub-module lasts four timetabled lab sessions with additional time spent outwith the lab to plan and analyse data. Sub-modules presently on offer include: Lasers, Signal Recovery, Electronics, LabVIEW, and Towards the Quantum Limit. These may change, for example as new experiments are introduced. Descriptions of the present sub-modules are given below. The class is divided into groups, usually of eight persons, which then circulate around the sub-modules sequentially. The structure of the sub-modules differs from one to another. In some, students work on the same set of experiments. In others, there are a number of experiments based around a common theme; following an introductory overview, students work singly or in pairs on specific experiments. Some of the sub-modules conclude with feedback sessions where students present the outcomes of their experimental work to their peers and staff or teaching assistants, followed by discussion. Other sub-modules aim at building basic skills such as in signal processing, electronics or computer-based data handling. All the experiments are up-to-date and relevant to the training of a practicing physicist, with a number of the experiments closely related to those found in contemporary research laboratories. The variety of approaches offered ensures that you will find this laboratory both enjoyable and stimulating. An initial module induction session is taken by the class as a whole and includes an important safety seminar, covering electrical, compressed gas, cryogenic and laser safety, followed by practical advice on the keeping of laboratory note-books and additional administrative information.

Aims & Objectives

To give you practical experience of some pervasive experimental techniques relevant to a practicing physicist, e.g. electronic design, computer-based data handling, signal processing. To introduce you to important contemporary developments in experimental physics, e.g. atomic force microscopy, lasers and nonlinear optical devices, electromagnetic traps. To strengthen your understanding of important physical concepts, e.g. quantum interference, atomic scattering, energy states and the Fermi level. To develop sound practice in a number of important generic skills such as planning of experiments, risk assessment, record keeping, data handling and evaluation, error analysis, drawing evidence-based conclusions, identifying future work. To enhance manual and mental dexterity at performing experiments. To develop transferable skills with regard to the presentation of research outcomes through both written work and oral presentations. To gain experience of carrying out experimental work while working alone, in partnership, and in small groups.

Learning Outcomes

You will have acquired: familiarity with a range of important and pervasive experimental techniques, practical experience of contemporary experimental equipment, including some used in present-day research laboratories, a fuller understanding of a range of important physical concepts through exploring them in experimental situations, key generic skills required by an experimentalist in the physical sciences, encompassing documentation, assessment, deduction, and presentation, ability to work both on your own and collaboratively.

Synopsis

LabVIEW (LV):

LabVIEW is an industry-standard programming and control environment. It is used throughout science and engineering as a means of creating programs and is ubiquitous in laboratories that require instrument control. A familiarity with LabVIEW is therefore a very saleable transferable skill. The purpose of this sub-module is to give the student an introduction to programming and the use of LabVIEW. By the end of this sub-module the student should be able to build a LabVIEW virtual instrument (VI) to undertake a specified task. The sub-module develops the student through finding out about the LabVIEW environment, ensuring they become familiar with the various windows, menus and tools. Next a simple VI is created, edited and debugged. The use of sub-VIs is discussed and two means of creating these undertaken; including setting up an icon and connector pane. Loops, program structures, arrays, charts and graphs are also introduced and used in the development of various VIs. The lab culminates in using LabVIEW’s control ability to interrogate a GPIB instrument simulator. The student learns how to communicate with a GPIB instrument and puts into practice some of their newfound skills in interpreting and visualising simulated experimental measurements. At the end of these four afternoons the student will have the skill needed to start using LabVIEW to tackle future projects.

Lasers (L):

In the first half of the sub-module the group will be working together investigating aspects of the longitudinal and transverse modes of lasers. This will allow students to explore important aspects of laser physics that also tie in with ideas in quantum mechanics and in oscillations and waves. The activities also develop aspects of experimental technique and the interpretation of the science behind various observations. In the second pair of afternoons students will work individually on their choice of one of a number of laser experiments. These may include various laser systems, conversion of laser light from one frequency to another, fibre optics, holography, remote sensing of speed with lasers, and the optics of optical data storage.

Electronics (E):

Electronics and in particular an understanding of its basic principles are invaluable skills in the Physics research laboratory. Whilst many designs are constructed and tested on the bench in a trial and error fashion, it is often highly desirable to be able to model the behaviour of a circuit on a computer to aid component value selection and hone its characteristics. Of particular interest in experimental research is the design and application of filters, which use capacitors, inductors, resistors or a combination of these. It is often very difficult to diagnose the characteristics of these circuits on the very short (transient) time scale, and so computer modelling becomes very important indeed. In this module you will be introduced to such a modelling program, (National Instruments - Multisim), and use it to investigate various simple circuits in the transient and steady-state regime to get a feel for how they react.

Towards the Quantum Limit (QL):

The invention of such devices as the atomic force microscope (although appreciated not strictly quantum) and the development of methods of electromagnetically trapping particles (e.g. Paul Trap), has taken physics to the quantum limit of ”seeing” entities such as individual atoms or molecules. The two-slit interference experiment when conducted with only single photons in the apparatus at any one time is another example of observation taken to the quantum limit. Materials science is one of the most active research fields today and needs serviced by new diagnostic instruments. The Kelvin probe is a non-contact, non-destructive vibrating capacitor device used to measure the work function (wf) of conducting materials or surface potential (sp) of semiconductor or insulating surfaces and we are fortunate to have in our teaching labs a state-of-the-art instrument from world leaders KPTechnology. These are the experiments that you will encounter in this sub-module. You will attempt one of these experiments over three sessions and the final session will be the feedback session in which students will discuss the perspective of their experiment, elucidate its conceptual foundations, present and evaluate their results, and reach conclusions for further discussion by the group as a whole; very much along the lines of presenting an invited paper at a conference.

Signal Recovery (SR): Just about any measurement you make as a physicist will be mediated by some form of electronics, and most transducers or measuring instruments will produce some kind of electrical signal. The main objective of this sub-module of the honours lab is to provide an overview of some fundamental ideas in signal recovery and processing including to understand the relationship between signal-to-noise in experiments and the data acquisition time. It will introduce some key concepts in the advantages and limitations of digitised signals, illustrate the principles and operation of phase sensitive detection, understand the utility of the fast Fourier transform in signal analysis.

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