PHYS 425/525: Modern Optics Laboratory (Spring 2005)

Instructor: Daniel A. Steck (with help from Steve Gregory)
Office: 277 Willamette      Phone: 346-5313      email: dsteck@uoregon.edu
Office hours: by appointment or drop-in
Course home page: http://darkwing.uoregon.edu/~dsteck/teaching/05spring/phys425

Schedule: TTh 5:15-8:15 pm, 12 Willamette (Optics Teaching Laboratory)
Course reference number: 38650 (425); 38651 (525)
Credits: 4
Prerequisites: none

Links: news, module documentation and assignments, presentation schedule.

Course overview

In this course you will learn optics the hands-on way, complementing the mathematical approach from last term. Modules ranging from geometrical optics to holography to basic photonic devices will give you a broad exposure to optical components as well as general laboratory techniques.

Primary Reference: Saleh and Teich, Fundamentals of Photonics

Supplementary References: These will be on 1-day reserve at the library:

• Hecht, Optics, 2nd ed. (Addison-Wesley, 1987). QC355.2.H42 1987
• Guenther, Modern Optics (Wiley, 1990). QC355.2.G84 1990
• Pedrotti and Pedrotti, Introduction to Optics, 2nd ed. (Prentice Hall, 1993). QC355.2.P43 1993
• Senior, Optical Fiber Communications (Prentice-Hall, 1985). TK5103.59.S46 1985
• Hariharan, Optical Holography, 2nd ed. (Cambridge, 1996). TA1540.H37 1996
• Lipson, Lipson, and Tannhauser, Optical Physics, 3rd ed. (Cambridge, 1995). QC395.2.L56 1995
• Young, Optics and Lasers, 3rd ed. (Springer-Verlag, 1986). QC355.2.Y68 1986
• Das, Optical Signal Processing (Springer-Verlag, 1991). TA1632.D355 1991
• Goodman, Introduction to Fourier Optics (McGraw-Hill, 1968). QC355.G65
• VanderLugt, Optical Signal Processing (Wiley, 1992). TA1632.V28 1992
• Iizuka, Engineering Optics (Springer-Verlag, 1985). TA1520.I38 1985
• Yariv and Yeh, Optical Waves in Crystals (Wiley, 1986). TA1677.Y37 1984

Grades

Grades for the course will be based mostly on individual lab reports (see below), but will also be based on an oral presentation and quality of your lab notebook:

• Lab Reports: 18% each (72% total)
• Presentation: 18%
• Notebook (spot checks during class): 10%

Lab Reports: The lab reports are formal written presentations of your experimental results. Although you will be working in groups of 2 or 3, I expect you to submit individual, independently written reports. The lab reports are to be written in the style of a research journal article. I will point out a number of features of your reports here that I consider important. However, since examples are the best way to establish what I expect, I have posted two reports that I wrote when I was a junior in college for a similar class (Advanced Laboratory, way back in 1993-4), including instructor's comments: coupled oscillators (pdf, 1M) and Fourier optics/spatial filtering (pdf, 396K).

Effective communication in writing is just as important as good laboratory technique and scientific insight. Your writings are how the rest of the world will know about your work. Therefore, I expect your formal reports to be of the highest quality.

Your reports should be typed, with 1.5 line spacing. Figures, tables, and equations should be included within the body of the text. Figures are best composed in a computer drawing package, but may be drawn neatly by hand (i.e., carefully drafted). Target length is about 10 pages; your reports will probably vary from 5-15 pages. Of course, the information content is much more important than length: 5 pages of insightful prose is vastly better than 15 pages with a low signal-to-noise ratio.

Your formal reports should roughly follow this basic outline (see the AIP Style Manual [1] for specific stylistic points):

• Title Page. The cover page should have the title, your name, and the name(s) of your collaborator(s). This page is generally not numbered.
• Abstract. Briefly describe the experiment and outline your major findings. The abstract should be brief, about 4 or 5 sentences, and should also appear on the title page.
• Introduction. Motivate the experiment and introduce the relevant theory, with mathematical details as appropriate to the later results.
• Procedure. Describe the experimental apparatus, including a diagram of the setup, and the procedures you used to set up the apparatus and obtain data. Discuss statistical and systematic errors, and how the experimental procedure and design mitigated these. Also be sure to address any questions posed in the module writeups.
• Results. Present your raw data and any calculations you performed to obtain meaningful quantities from the data. Remember that data are meaningless without both units and error estimates! Use plots or tables as appropriate to the particular data. Provide titles for tables and captions for figures.
• Conclusion. Discuss conclusions drawn from your experimental data and their broader scientific meaning. Comment on what you would do differently if you had to repeat the experiment, and suggest improvements in the experiments for the future.
• References. Cite any references (textbooks, articles, reference books) you used in the text. This applies, for example, if you copy a diagram, follow a derivation, quote a passage, etc. from a textbook. Follow current AIP Style Manual [1] for citation format: cite the work in the text by using a citation number in square brackets, as in the examples here. In the bibliography section, list the same numbers with the citation afterwards. See Refs. [1-3] below for examples on citation format. Notice especially the book format of Ref. [2] and the article format of Ref. [3] (the volume is listed in boldface, followed by the starting page number and finally the year in parentheses).
  
  [1] AIP Style Manual, 4th ed. (American Institute of Physics, New York, 1997). Available online at http://www.aip.org/pubservs/style/4thed/toc.html.
  
  [2] P. R. Bevington and D. K. Robinson, Data Reduction and Error Analysis for the Physical Sciences, 2nd ed. (McGraw-Hill, New York, 1992).
  
  [3] A. L. Schawlow and C. H. Townes, “Infrared and Optical Masers,” Phys. Rev. 112, 1940 (1958).

Your formal reports will be graded on clarity and correctness of the above items, as well as grammar and overall professionalism of presentation. Also, of course, on the quality and correctness of your experimental results, as well as the extent and creativity of your experiments.

Presentation: Effectiveness in oral communication is also vital in any technical career. Often, the first time people become aware of your results is when they hear you present your results at a conference or in a smaller meeting. Your effectiveness in communicating your ideas and enthusiasm will determine their professional impression of you as well as whether or not they will continue to seek out more information about your work.

The presentations will be individual, and run 8 minutes with 2 extra minutes for questions. They will be held on the last day of class. You will pick one experiment to talk about. You may choose to present your own talk or part of a “super-long” talk on one experiment with your collaborators. In the latter case, each part will be treated as a separate presentation with questions between.

A good technical presentation is difficult to characterize in general (“you know it when you see it”), but here are some guidelines:

• Start by posing an interesting question or idea, particularly one that is nonintuitive (“common wisdom states that ..., but as it turns out, that doesn't happen ...”). This will capture the attention and imagination of the audience, and make them look forward to what you have to say. I do not suggest starting with a laundry-list outline of the sections of your talk, which is one of the best ways to put your audience to sleep right at the outset.
• Communicate the necessary theoretical background, but be merciful! No one wants to stare at page after page of long equations. Equations are acceptable if they are simple, familiar, or absolutely essential to making your point. In the kind of presentations you will do here, the ideal number is about 1. It is far more effective to make your point with sketches and plots.
• Make sure all your transparencies have clearly readable text for audience members at the back of the room. That means 18-24 point type minimum when using a computer to make your presentation. All your graphics should be clearly legible as well, including plot axes, legends, and diagram labels.
• Keep to a reasonable pace and length. For a 12 minute talk, you should have about 8-10 transparencies, depending on the information density and your pace. Practice the talk and time yourself beforehand to make sure the length is correct.
• Thank the audience at the end of your talk for their attention. This is their cue that you are in fact finished speaking and to applaud. You need not ask them if they have any questions, as this is usually the role of the moderator.
• Until you get good at this sort of thing, it will probably be a nerve-wracking experience. The only reliable way to combat pre-talk anxiety is preparation. If necessary, rehearse until you can go into tape-recorder mode. With sufficient preparation, the adrenaline rush that accompanies your talk can immensely boost your performance; otherwise, it may make your performance substantially worse.

Lab Notebook: You should record all your raw data, sketches of your setup, derivations, etc. in a research laboratory notebook. A properly kept notebook will serve as a complete but informal writeup of your results, which you will later change into your formal writeup. Good notetaking habits are extremely important in professional laboratories, especially in industry. A properly documented notebook can serve as legal documentation of your research in the case of a patent dispute.

Note that proper practice requires each page of the notebook to be signed and dated each day in the presence of a witness who also signs each page; good notebook procedure also dictates that carbon paper be used to create duplicates of each page. I will not expect you to be this formal, however I will expect you to take extensive notes in your own notebook. Even when, for example, you take data on the computer or via an oscilloscope plot, you should still paste a copy of the data into your notebook.

A proper lab notebook has a durable binding on the left side, 50-100 numbered, duplicate pages, and measures 11"x9.25". The front cover is typically a mottled reddish brown, but the UO bookstore currently has notebooks with light grey covers.

Since you will need your notebooks to do the lab work and make the formal reports, I will not collect them. Rather, I will simply conduct random spot-checks during class time.

Experiments

See the modules page for a list of the available laboratory modules, along with which modules are assigned to your group. The documentation is available online here. You should read the module materials before coming to class, including looking up any necessary supplementary reading in the library references listed above.

The general idea is that you will start each module with a blank optical table and a supply of relevant equipment. You will construct setups as necessary to make measurements, with both me and the writeups as a guide. When your time on the module is completed, you should break everything down and return the equipment to the initial state.

Also, since you can look at the various modules, look ahead to see which ones you'd like to do in the future, and let me know well in advance so I can make sure you get to the ones you want.

Philosophy of this Course

Typical physics curricula heavily emphasize theoretical coursework. Unfortunately, this does not match the training needs of physics students very well. According to a recent Physics Today article by Kirby, Czujko, and Mulvey, experimental physicists outnumber their theoretical counterparts by a ratio of about 2 to 1 at the new Ph.D. and university faculty levels, with even larger ratios in government laboratories and industry. Yet experimental methods typically account for only a small fraction of formal coursework in physics, even for students who will eventually focus on laboratory work. Obviously, experimental physicists need sound training in theory to understand the basis and meaning of physical measurements. However, the converse is also true: theoretical physicists benefit greatly from knowledge of laboratory methods and technology. This ensures a common language shared by theorists and experimentalists, which is absolutely crucial in the physical sciences. In fact, the interplay between theory and experiment is the very way in which the scientific method works in the physical sciences.

The goal of an advanced laboratory class such as this is to further you as a scientist. More obviously, this happens by learning laboratory technique, such as developing dexterity with equipment and an intuition for how to make things work. As well, you will spend longer periods of time with particular subjects and problems than you would in a lecture, allowing you to go much more in depth in certain areas. However, experimental physics is also an inherently creative pursuit, forcing you to figure out how to design a complex apparatus and how to push your equipment to its limits to get the best possible measurement. Laboratory science also pushes your ability to think critically: your apparatus may be trying to fool you, so you must constantly devise tests to make sure of what you are seeing, and when one of many possible parts of the apparatus fails you must be able to debug things and home in quickly on the problem. Finally, as I mentioned above, you are usually exposed to the “finished product” in terms of physical theory in lecture-type classes. Here, you will see firsthand the testing ground that these theories have survived time and again until they made it into textbooks.

Therefore, while you will have access to writeups for the experimental modules, ultimately you are responsible for the direction and accomplishments of your experiments. With this in mind, you should regard the writeups as being a rough guide, with the details of the experimental apparatus and experimental procedure being up to you (within the limits of the available equipment). My role is to help you gain competency with the equipment and help you understand the physics, the primary goal being to facilitate your posing and answering scientifically interesting questions for yourself. This is a crucial part of your development as a creative and independent thinker.

Schedule

Nominally, each lab should take 2 weeks (4 class periods of 3 hours each). This is a rough schedule; some of the projects will be extended slightly depending on their difficulty (the first module will be 5 class periods to help get things started). See the module assignments page for your group's actual schedule.