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					Physics 316                                 Optics                                Spring 2011


                                     General Information

    Instructor:                 Professor Yan Mei Wang                        213 Crow
                                                                ymwang@wuphys.wustl.edu
    Lab Coordinator:               Dr. Scott Handley                      167 Compton
                                                                   smh@wuphys.wustl.edu

                       Class website: http://physics.wustl.edu/classinfo/316/

    The course provides an introduction to ray and wave optics and to the handling of
    experimental data. You will be required to show a good understanding of the physics
    involved in a series of experiments and to demonstrate proficiency in the reduction and
    interpretation of data.

Textbook
   • Optics, E. Hecht, 4th edition (Addison Wesley, 2002). A few copies of this book are in
      the laboratory for reference during experiments.
   • This website gives a really good tutorial to the basics of error analysis, such as how to
      report the reading of a ruler. http://phys.columbia.edu/~tutorial/
   • An Introduction to Error Analysis, J. R. Taylor (University Science Books);
   • Data Reduction & Error Analysis for the Physical Sciences, P. R. Bevington (McGraw-
      Hill).
    Note: The books are on reserve in the Physics Library and the purchase of books are
        optional.

Format
   Two 4-hour sessions per week on Tuesdays and Thursdays, Crow 306 from 1 to 5 PM.

    In the laboratory, you will work in pairs, but each student should maintain individual lab
    notes which will provide the basis for preparation of individual written lab reports, to be
    submitted for evaluation following completion of each experiment. During the semester you
    will carry out 7 different experiments. Seven completed and graded experiments are
    required to obtain a passing grade in the course.




                                                1                                    Syllabus
Physics 316                                   Optics                                 Spring 2011


Evaluation and Grading
   Numerical grades will be assigned to students individually for each completed experiment.
   The overall distribution will be 80% experiments, 20% preparation and independent
   problem solving. The experimental lab report grades (100 pts each) will be based on the
   following considerations:

        a)     20 pts: Understanding of the relevant physics. Write up your understanding of the
               physics principles of each experiment in the Aim/Objective section of the lab
               report. Use these principles throughout the experiment for data analysis,
               interpretation, and problem solving.
        b)    20 pts: laboratory procedures and quality of measurements. You should keep your
               notebook in the form of a journal, with an entry for each day you are in the lab,
               even if not much happened. You should write your notes assuming that someone
               is going to repeat your work with the same apparatus. Be sure to note everything
               that could have affected your results or caused problems.
        c)      20 pts: presentation, treatment, and interpretation of experimental data. This
               includes clear presentation of tables, as well as reporting units and error estimates
               on all data. If you are calculating a quantity or converting measured values to
               something else, show an example of the full calculation once.
        d)    10 pts: error analysis.
        e)    10 pts: conciseness and clarity of the laboratory report. You don’t need to write
               every detail of everything, only the relevant ones to the experiemnt that happens
               each day, using simple and clear language.
        f)    20 pts: answers to questions in the write-up of each experiment.
        g)    10 bonus pts may be given to students that put in extra effort. What sort of efforts,
               talk to the instructor.
        h)     Lab reports are due ONE WEEK after completion of the experiment (unless
               otherwise specified in class).
        i)     5 pts will be deducted for each day the Lab Report is overdue.
        j)     10 pts will be deducted if equipment is not returned to the original location and
               stored properly at the end of each experiment.

    Meaningful originality and extra work will be taken into account, as will also constructive
    ideas and contributions beyond the requirements. Suggestions for improving the course
    notes are welcome.

Laboratory Rules
   1. No smoking, food, or drinks in the laboratory
   2. The laboratory equipment is sensitive, so please treat it with care.
   3. Handle optical surfaces like lenses and mirrors with gloves.

                                                 2                                       Syllabus
Physics 316                                 Optics                                Spring 2011


     4.   Return all optical elements and equipment to proper storage locations (Points will be
          deducted if equipment is not returned to storage location and stored properly). For
          example, if an optical element is removed from a package, it must be returned to that
          package.
     5.   Do not open any instruments unless specific instructions have been given by the
          instructor.

Laboratory Safety
Lasers
    NEVER LOOK DIRECTLY INTO A LASER BEAM OR INTO ITS STRONG
    REFLECTION.
    Ordinary low-power, classroom lasers produce optical irradiance which can be about 1000
    times greater than a safe level if viewed directly or in specular reflection. A "safe" level
    recommended by the American Conference of Government Industrial Hygienists (1968) for
    daylight illumination is 5 x 10-5 watts/cm2. A 1-milliwatt laser with a beam diameter of 1.5
    mm at the aperture produces about 6 x 10-2 watts/cm2 at the aperture, a value about 1000
    times greater than this "safe" value. Even 40 feet away such a laser may produce about 6 x
    10-4 watts/cm2 in the direct beam, a value 10 times greater than the proposed safe level.
    Therefore, use great caution with lasers. It is almost always unsafe to view an unfiltered or
    undiverged laser beam, either directly or in specular reflection. Otherwise, permanent
    damage to the eye may result.

UV and High-Intensity Lamps
   Take adequate precautions to avoid unnecessary exposure of eyes to ultraviolet radiation and
   the other high-intensity lamps.

Power Supplies
   Some experiments may require the use of high voltage power supplies. Ensure that proper
   precautions are taken in the use of cables and connectors for these supplies. Never open the
   covers to make modifications or correct problems. Please report any problems with the
   supplies to the TA or instructor.

Syllabus
Course Objectives
The course has three general objectives:

1)   Introduction to Optics
     This course provides an introduction to experimental optical physics, optical
     instrumentation and optical metrology. The emphasis in the experiments is on the physical
     principles involved and on the basic physical phenomena such as refraction, polarization,

                                               3                                      Syllabus
Physics 316                                 Optics                                Spring 2011


    dispersion, interference, diffraction and image formation. All experiments are quantitative
    and usually they involve observations, measurements, data analysis and interpretation! The
    experiments are open-ended and there is ample opportunity for optional extra work.

    The write-ups that are provided for each experiment are deliberately quite brief to encourage
    you to develop your own ideas on best ways in which the experiment can be carried out with
    the existing apparatus. The write-ups should be treated more as guides rather than a specific
    set of instructions to be followed.

2) Introduction to Experimentation
   Physics is an experimental science, and even the most ingenious and plausible physical
   theories cannot he accepted without experimental verification. Properly carried out
   experiments in conjunction with careful data analysis and interpretation are the basis for our
   knowledge and understanding of the physical world.

    This course is designed to develop good laboratory practices which; as a rule; are
    indispensable in any meaningful experimental investigation. These practices include:
    planning and designing an experiment, adjusting apparatus for optimum performance,
    keeping adequate records, carefully analyzing and interpreting data; together with the
    preparation of a lab report including a clear summary and conclusions section.

3) Treatment of Experimental Data
   The analysis of your data will be significantly more detailed than in the introductory physics
   courses such as Physics 117 and 118. You will be introduced to some statistical techniques
   and analysis of data obtained in the lab. In most cases the objective is to calculate the best
   values of various measured quantities and to determine their uncertainties. Careful analysis
   of experimental uncertainties (errors) is not only an indispensable part of any measurement;
   but it also provides the basis for further improvements in measurement methods and
   experiment design.

References
    You will probably find Palmer (Optics) useful as additional references beyond the text. In
    addition you may want to look at other references on reserve, such as:

              Class Notes                          Online
              Born and Wolf                        Optics
              Jenkins and White                    Fundamentals of Optics (4th ed.)
              Smith                                Modem Optical Engineering
              Pedrotti                             Introduction to Optics


                                               4                                      Syllabus
Physics 316                                 Optics                                 Spring 2011



    Handbooks (on the Reference shelves in the Physics Library): American Institute of Physics
    Handbook, Handbook of Chemistry and Physics (C.R-C- Publishing Co.) (Don't go out and
    buy a copy; last year's issues are sold each year at discount by the publisher; wait for the
    sale.) Handbook of Optics (Optical Society of America)

    Note: Some of these references together with a collection of other relevant materials are
    also available in the Physics Library.

Office Hours
    We will be in the lab during the regular lab times; there will be plenty of time for questions
    and discussions. Should you need assistance at other times, feel free to email the instructor
    for addition meetings.




                                                5                                      Syllabus
Physics 316                                  Optics                                 Spring 2011


                          Course Organization and Laboratory Reports

I. Experiments
The experiments available this semester divide into two broad groups:
    The A experiments are mainly concerned with geometrical optics and with instruments, and
    B experiments with wave optics.

Core Experiments:
    The three core experiments have been alloted 4 classes each for completion.
        A1       Thin lenses and lens combinations
        A3       The prism spectrometer
        A5       Lasers and polarization

Additional Experiments:
   Four of the remaining seven experiments have been alloted 4 classes each.
        A2       Longitudinal chromatic aberration
        A6       Thermal radiation
        B2       Fresnel's biprism
        B3       The grating spectrometer
        B4       Michelson's interferometer
        B5       Fresnel diffraction
        B7       Fraunhofer diffraction and Fourier transforms

The three experiments marked "core" will be carried out by all groups and will be completed in
        the first six weeks. Following that, 4 more selective experiments will be performed.

II. Lab Procedures
    Care of optical equipment: keep fingers off all active surfaces; if you have to touch an
    active surface, use a lens tissue to protect the surface. Handle lenses and mirrors at their
    edges. It may still happen that a surface becomes dirty (fingerprints or whatever). Under no
    circumstances should you simply rub a surface to clean it. Cheaper, uncoated lenses can be
    cleaned with a soft tissue and a solvent, or with a soft Q-tip, but high quality surfaces must
    not be rubbed. (Rubbing can too easily grind dirt particles into the surface.) If necessary, we
    can use an ultrasonic cleaning bath for a small component.

    Read experiment notes and instructions before coming to the lab. While many of the
    detailed points will become clear only after you have actually handled the equipment; you
    should at least have a general idea of the experiment before you start taking data. Adequate
    preparation will make all the difference in your efficiency.



                                                6                                       Syllabus
Physics 316                                 Optics                                Spring 2011


    After getting the equipment set up; go through quickly and take some rough measurements;
    then do a rough calculation. This will check that there are no serious problems. Then start
    your careful data taking.

    Be alert to possible extra measurements or extensions of the experiment. Check with the
    instructor or T.A. if you need additional equipment.

    Allow adequate warm-up time for the Hg and Na lamps and lasers in those experiments
    where you need to measure the intensity of the light. These lamps need about 20-30
    minutes; so you can either switch on when you enter the lab or else get the labs opened
    before the lecture, to allow you to switch on. Experiments can be left fully set up from one
    lab period to the next.

    Some of the equipment is old but still good. Handle everything with care. The experiments
    and the apparatus are currently being upgraded.

    Please let us have your comments and suggestions, so that we can continuously improve our
    experiments. Also, please report promptly if any equipment is damaged or nonfunctioning.

III. Writing Laboratory Reports
Notebooks
     Use 3 copies of lab notebook type 77-620 (spiral) or Computation Note Book #77-648 to
     record your experimental work in ink (except for data points for graphs, schematics or other
     drawings, which may be in pencil). With three notebooks, you will be able to have one for
     your current experiment while one is being graded and the third is being prepared for
     handing in (with your previous experiment).

    All the steps in your experiment, including rough calculations, derivations, etc. must be
    recorded neatly in your lab notebooks. Remember to always put the date(s) for the
    experiment.

    All graph papers and any other external sheets used must be affixed permanently to the
    notebook. Graph paper may be downloaded from the optics website.

    Do not overwrite or tear out pages. Identify mistakes in data recording, etc. by placing a
    line across the error.

    While you will work in groups, the data collection, analysis etc. must be shared responsibly.
    Both members in a group must submit individual lab notebooks. Individual differences in



                                               7                                      Syllabus
Physics 316                                Optics                                Spring 2011


    the understanding and interpretation of data must be maintained and reflected in your lab
    notebooks.

    This lab will stress the use of hand calculations in the analysis of data and its errors.
    Therefore, computer based analysis will not be acceptable. However, you are welcome to
    compare your results with similar analysis using graphical packages done on the computer.
    In fact, you may find it extremely useful to especially compare least squares analysis with
    the values obtained via packages like Kaleidagraph, Excel, etc.

    Follow the attached guidelines for the presentation of your experiments and results in your
    notebooks.

First Page of Lab notebook

    Date of          Group        Experiment Name/Number          Page(s)        Comments
  Experiment
  01/07/2011            1          A1-Thin lenses and lens         2-10          completed
                                       combination




First Page of Report
    Experiment number and Name: for e.g. A1 - thin lenses and lens combination

    Aim/Objective: In your own words describe briefly the objective of this experiment.
    Following this you should make an attempt to intuitively analyze the experiment till its
    conclusion. This section can be treated as a "thinking aloud" of the experiment as it would
    be performed if it were a gedanken or thought experiment. In other words, your intuitive
    understanding of how the quantity will be measured should be clearly visible in any
    description you put down in this section. This section should be brief and in most cases 2
    pages should be sufficient. Use only the right hand pages for this section.

    To help you in your thought process, you may use the left hand side to make a bulleted
    summary of some of the key steps played out in your mind to carry out the experiment. At
    the end of this report, you will end by comparing the actual steps you took to some of the
    steps you thought you would.

Experimental procedure and tabulated list of apparatus
   This section must also be kept to the right hand pages of your notebooks.


                                               8                                    Syllabus
Physics 316                                 Optics                                 Spring 2011


    Detail the various steps that you feel were necessary to successfully carry out the
    experiment, with a brief explanation of why the step was required. For example, you may
    find that the leveling of some components was essential and required additional tools, like a
    liquid level.

    The steps that you record here need not include the important ones outlined in the
    experiment handouts. However, if you find that you could or did use an alternate approach,
    you must record it.

    To tabulate the list of items, follow the systematic approach shown in the table below:

    Item Name             Serial# or Other ID#           Quantity          Comments
 He-Ne laser         Spectra-Physics S# ABCD123             1     Had to use a special stand to
                                                                  help in alignment of the
                                                                  laser




    Note: you do not need to include basic tools like screwdrivers, etc. However, if you find
    problems or made some modifications to existing tools please record it. It will help us in
    improving the quality of the tools that we provide. Use additional pages for the table as
    necessary.

Schematic of experimental set-up: (Can be done in pencil)
    Using the left hand page, neatly outline the schematic of your experiment. If possible use
    the notations in the handouts to mark the key dimensions on your drawing. Use similar
    notations in the collections and analysis of your data to follow. Ensure that the schematic is
    tidy by using rulers, etc. to make your drawings. A computer should not be used to create
    the schematics.

Measurements, Calculations, Analysis and Results
   Record neatly your data, formulas, derivations, etc. As far as possible use tabulated data and
   use the right hand pages.

    Clearly define the sources of error in your measurement and estimate them. Where
    appropriate, the mean values, their standard errors, best estimates using statistical
    procedures, any discrepancies and/or inconsistencies must be evaluated. (Error analysis is
    discussed in the handout posted in the class website).




                                                9                                      Syllabus
Physics 316                                  Optics                                  Spring 2011


    The number of significant figures used in presenting the standard error of a mean value is
    usually two significant figures, e.g. 0.12 or 5.3. The number of significant figures in your
    final best value must then match that of the standard error of mean. For example 4.3 0.12 is
    right, but 4.374 0.12 is not.

    All graphs and plots must be on the left side. Use graph paper to plot your data and then
    affix the paper to the left side. Use clearly labeled axis and titles for the graphs. The source
    and magnitude of the error bars used must be clearly mentioned. Use least squares fitting of
    your data points wherever appropriate.

    All rough calculations etc. should also be restricted to the left side, with a clear header
    indicating so.

Discussion and conclusion
    You should end the report with a brief summary of your experiment and its results. A good
    format to follow for this section is that of a widely circulated journal like one published by
    the AIP, for example the Applied Physics Letters.

    You must also add a discussion of your understanding of the experiment. Ideally, you
    would now like to compare the experiment to your original thought and put down the
    various aspects of it, especially the physics related ones, that you found to be interesting and
    unanticipated.

    You may also add a brief comment or two about any serious problems you had (if any) in
    performing the experiments. Note, you can also do this in the comments section at the
    beginning of your lab notebooks.




                                                10                                       Syllabus

				
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