Lab 17

Lab 17 is the class wrap-up, the traditional trip down memory lane with bonus topics.  Meet in the classroom.  Attendance is mandatory.  There is some essential paperwork.

Final pdf's of your presentation slides are due to me via email by the end of the night.  I will package them all up onto CD's for distribution next Monday evening.  These are the versions you will present.  From all indications, they are going to be pretty good.

I am planning to have open lab at 5 PM (not 4) for an hour.

Lab 16

For Lab 16 we will meet in the lab.  There is no classroom session.

In Lab 16 we build and get fringes on a Sagnac interferometer, which forms the basis for laser ring gyros.  There is no prep as this is just a familiarization exercise.  Upon its completion you will have the skills to construct the three main types of interferometers.  Be sure to capture the build in your lab notebook.

Lab will be open Sunday 1-6.

Project schedule update

I am noticing that the dates noted earlier for the final presentation were not right.  Seems the end of the quarter is sneaking up faster than I thought.

Presentations will be given December 3 7:00 PM to 10:00 PM during the scheduled final examination time in the classroom.  Feel free to invite friends, family.

Your final pdfs are due on Wednesday November 28.  Please be sure your plans reflect this.

Lab 15

Lab 15 Briefing Material (pdf file)

Lab 15 Prep:

1.  Download the briefing materials and read them.  Perform the work needed for items #2 and #4.  Record results in your lab notebook.  In lab you will carry out these procedures and calculations.

2.  You will need to determine the thickness of the microscope slide with a micrometer.   We have a bunch of slides but the micrometer has a minimum jaw width of 1 inch (maximum is 2 inches).  Think of at least one way that this seemingly unfortunate circumstance is an opportunity for higher precision.

3.  Generate an error budget containing at least 4 important contributions.  How accurate do you expect your refractive index measurement to be (numerically, as a percentage)?

Don't forget slide titles are due as well - emailed to me.  Take note that your presentations will only be 10 minutes long.  So you will only need a small handful of slides.  5 would be a lot.  Those of you in teams identify who will present which slides.

Also:  those of you who need equipment for your projects from the Physics storeroom be sure to work with Brian and Al to arrange its use asap.  They are expecting you and waiting to be helpful to you.

Lab 14

Lab 14 Briefing Package (pdf file)

Lab prep involves notebooks and your final project.

Lab notebooks:  those of you who did not get a bye, please be prepared for notebook review

Project / Final Presentation:  Prepare a page that...

• Succinctly describes the project
• Identifies your project team
• Estimates the amount of table time needed
• Estimates the amount of other time needed
• Presents a schedule of activities that delivers a pdf version on the last day of classes
• Includes a plan to obtain any needed equipment not in the lab
• You email to me and have available in class for review

I have scheduled a large number of open lab hours between now and when the final presentation pdfs are due.  These are listed in the immediately previous post.  

Open Lab Hours

Open lab this week:

   Monday 4-6 & after class

   Tuesday 4-6 & 7-9

   Wednesday 4-6 & after class

   Sunday 1-6 by appointment

   

Open lab next week:

   Monday 4-6 & after class

   Tuesday 4-6 & 7-9

Since open lab hours are limited, please plan your project work to be efficient on the table.

Project Ideas

The ultimate Malus Law experiment

Interference patterns from single photons

The optical table as a giant thermometer

Optical table guitar

Mach-Zender interferometer to measure water salinity

Detection and isolation of quantum optical vortices

Polarization rotation vs polarization filtering

Optical magnetometer

Up/down conversion of orbital angular momentum states

Camera vs radiometer calibration

Some projects that are being worked on:

Refractive index of air

Optical quality of photolithographic sheet material

Telescope repair and alignment

Faraday rotation in magneto-optical materials

conformational response of photo-active polymers to illumination

Lab 13 Materials

Lab 13 continues our exploration of the Michelson interferometer.  In the prep package you will work through some alignments, make predictions of experimental outcomes, and complete the quantum mechanical calculation we started in the last class's "Quantum Snippit".

Lab 13 Prep Package (pdf file)
Lab 13 Briefing (pdf file)

Here are the fringes seen in the 2 interferometers built by teams Mir and Skylab for Lab 12:

Team Skylab Fringes

Team Mir Fringes

Project Schedule

Teams due 11/14   A team is one or two people

Topics due 11/19 Reviewed in class
                           have a second choice available

Slide titles due   11/21 Reviewed in class (pdf)

Draft charts due 11/26 Describe the content (pdf)

Final charts due 12/05 What you are presenting (pdf)

All items to be sent to my by email by class on the dates noted.  I will hand out CD's containing the files at the time of the final presentations.

You may accomplish these milestones early if you wish, but certainly no later than the dates noted.  You will avoid a rush at the end, and competition for lab equipment, by doing your projects early rather than at the last minute.

Lab 12 Materials - Michelson Interferometer First Fringes

Lab 12 Prep Package (pdf file)

Lab 12 Briefing (pdf file)

It's a happy circumstance that today's easily available optical components and mounts allow the construction of various interferometers on the optical table.  It means we can have a lot of fun with quantum optics by being hands-on, and in doing so gain good physical insight.  In this lab we start our sweep through the final theme of the class where we'll bring all of the ideas together into sophisticated probing of the quantum state of light in interferometers, fringe formation, and illustrations of the which-way ambiguity.

For prep you will read Michelson and Morley's original paper, explore some new interferometer concepts and get concrete about carrying out the alignments necessary to get an interferometer to work.

Lab 11 Materials

Lab 11 Prep Package (PDF file)

We will be probing image formation by a telescope mirror and trying out optics cleaning techniques (deferred from last time).  If you do not have a "bye", be prepared for notebook review.

We will head over to the lab from the classroom immediately after the prepared/not-prepared session.

There is open lab from 5 to 6 on Monday and again from 5 to 6 on Wednesday.

Projects:  several students have started on their projects, ahead of schedule.  That's fantastic since later in the quarter table time will be a premium.  Another reason to get a head start is if your project needs us to fabricate or purchase something, then it's good to schedule time for that upfront.  These so-called "long-lead items" that always need attention paid early on in a project.

Lab 10 Prep

First a note on Lab 9X.  All I can say is "Wow!"  We got organized and got that done really efficiently. Things to note:  good prep really helps.  Good planning really helps.  Good organization really helps.  Good communication really helps.  And a clock tick can help too.  (But don't be a slave to it).  What really makes it work though is good teaming.  

Each team please asap email me your data from the experiments done Monday in lab; I will post them on the blog along with the error term analyses and procedure updates.  Analyzing the data is optional.

Lab 10 Prep Pkg (PDF File)

There are no briefing materials for Lab 10.  We will be discussing image formation and optical systems, working with telescope optics on the table, and learning cleaning techniques under the hood.

Lab 9X Prep

Lab 9X will finish off Lab 9, which is too long to do in a single session.  For the prep you will need to work in your 3 groups to come to consensus on your work product.  These are what we discussed in class on Wednesday.  Each team will need to email me pdf's of the two work products before lab.  Each team please also bring 4 hard copies.  One of these copies will be used in the briefing via the overhead projector camera and the remaining three will be distributed among the teams.

Team Mercury:

1)  Determine your team's best value for the error introduced by background light and its drifts.  You will have 2 parts to your analysis:  one regarding the background drifts, and another that explicitly considers the background contribution to the signal in the measurement of I(theta).  You can use any reasonable units you wish as long as they are quantitative.  Generate a 1-page pdf describing how the error values were estimated, and report the values.

2)  Generate a procedure to minimize the errors due to background light in an improved version of Lab 8's Malus' Law experiment.  Generate a 1-page pdf describing this procedure adequate for sharing with the class

Team Gemini

1) Determine your team's best value for the errors introduced by human factors.  You can use any reasonable units as long as they are quantititive.  Generate a 1-page pdf describing how the values were estimated, and report the values.  

2)  Generate a procedure to minimize the errors due to human factors in an improved version of Lab 8's Malus' Law experiment.  Generate a 1-page pdf describing this procedure adequate for sharing with the class.

 

Team Apollo:  

1)  Determine your team's best value for the error introduced by laser drifts.  You can use any reasonable units you wish as long as they are quantitative.  Generate a 1-page pdf describing how the value was estimated, and report the value.  

2)  Generate a procedure to minimize the laser drift error in an improved version of Lab 8's Malus' Law experiment.  Generate a 1-page pdf describing this procedure adequate for sharing with the class.

Lab 9 Materials Available

Lab 9 Prep Package (PDF File)
Lab 9 Briefing Materials (PDF File)
Sample Lab 8 Data for inspection/reference (PDF from Google Spreadsheet)


Lab 9 will build on the good success of 8X.  Here we are adding the idea of an error budget to the idea of an experiment design.  An error budget considers all of the effects that lead to uncertainty in an experiment's results.  By estimating each effect and rolling them all up into a total error you have a good idea of the quality of results you can expect.  An error budget is also a good debugging tool.  If you see more error than expected in a measurement, you can check each term in the error budget to see where either an assumption is wrong or the apparatus is misbehaving.  This provides a systematic way for you make corrections.

Lab 8 Wrap Up / Lab 8X Prep

Lab 8 is one of my favorite labs.  It's where the rubber really meets the road in terms of an experiment, and where the teams really need to work together to get the work done efficiently.  This year the teams are bigger, but you all rose to the challenge and organized yourselves quickly.  It's too bad we don't have a couple of extra radiometers and rotating polarizers - things would go faster and the teams could be smaller for this experiment.

Three things are just plain true that slow us down a little compared to last time the class was taught.  First, we have more people in the class.  Another is that the classroom is in another building from the lab so we have to spend 5-10 minutes in transit.  And finally, we start half an hour later, and folks still want to get home at a reasonable time, so the open lab time is shorter.

And so we didn't quite finish.  Another half-hour would have done it.  We'll wrap it up next time, starting with 8E and moving to 8F.  We'll call this combo Lab 8X (for 8-extended).

For Lab 8X prep, complete the following tasks:

1.  Make sure your data for experiment 8A-8D is complete and recorded in the proper format.
2.  Write down at least 3 good questions you have about the experiment or your data.
3.  Compute how many laser photons at a time were in your polarizing filter.  Record explicitly any assumptions you needed to make.
4.  Enumerate the 6 mechanical degrees of freedom (three coordinates and 3 angles) of the polarizer in its mount and how those degrees of freedom are made repeatable each time when the mount is blocked on the table.

A polarizer in its mount blocked on the table with 3 bolts

The other polarizer on the table, but unblocked

Finally, the lab will be open 5-6 PM this coming Monday, October 22, with the table set up for Lab 8.

Lab 8 - Quantitative Polarization Prep & Materials

Lab 8 Prep Package (PDF file)

Lab 8 Briefing Materials (PDF file)

Prep involves watching a video lecture where Walter Lewin describes Malus' Law, the topic of our lab.  There are now a huge number of physics lectures on-line.  These are an incredible resource for learning.

Lab 7 Prep and Materials

Lab 7 Prep Package (PDF File)

Lab 7 Briefing Material (PDF File)

Bring some small transparent items.
We will meet in the classroom first, then move over to the lab.

Lab 6 - Retrospective on Lab Notebooks

In lab 6 I spent 5-10 minutes one-on-one going over lab notebooks. These were good discussions.  Some comments:

1. There is a wide range in style.
2. Several students are using electronic notebooks.  Some of these are local applications and some are in the cloud.  If yours is a local application be sure to back up the content!. There is a wide range in notebook quality.
4. Not everyone seemed satisfied with their notebooks.
5. Here's a strategy for improving your notebook:
--- Refer to the checklist in the material for Lab 1.
--- Review your notebook against the checklist.
--- Pick an area to improve.
--- Spend extra effort on that area until you see improvement.
--- Iterate.
6. Some notebooks didn't record lab procedures. These are necessary to reproduce a result.  Imagine you will be handing your notebook to a colleague who will use your notes to re-do an experiment.
7. Good notebooks can save you in the future from extra work redoing stuff that you just didn't bother to record. Get in the habit of recording a little more than you think you need to.
8. When something is puzzling, make a note of it in your notebook.  A puzzle is meant to be solved.  Solving puzzles yields understanding.  You should not just let an inconsistent result stand without tracking it down or at least making an obvious note of it.

Except for those of you to whom I gave a "bye" for further rounds, I will review lab notebooks in class again. At that time we will make "improvement contracts". In the meantime, use the feedback provided and these comments as an opportunity to improve your practices. Out in the wild you will find it necessary to keep good lab records in order to make reliable progress on a project and be confident of the results.

Lab 6 Briefing

Meet in the lab, Wing B 144, instead of the classroom.

Hard to believe we're already finishing week 3. That means it's time for lab notebook review, so prep this time is to catch your lab notebook up-to-date and be prepared to show it to me during the next lab session. I'll spend 5 or so minutes with each of you assessing notebook quality. There will be 2 possible outcomes:  (1) you've got an acceptable notebook and you're good to go - you've got a pass on further notebook review. And (2), I'll be reviewing your notebook again to see how you are improving based on the advice I give you. Notebook quality is not directly a part of your grade, it only counts so far as good notebook quality helps you otherwise get a good grade. So treat this as a no-risk skill-building exercise. Good lab notebooks are essential - without good notes all you are doing is experiencing.  Without records you can not really do science since a key aspect of science is it's repeatability.

Lab 5 Briefing Materials Available

Lab 5 - Interference Fringes (PDF File)
Lab Self-Assessment Rev 2 (PDF File)

Lab 5 Prep Package Available

Lab 5 Prep Package (PDF File)

... in which you explore small angles, analyze Lab 4's data and design a small part for an experiment.

Lab 4 Materials Available

Lab 4 Prep Package (PDF File)
Lab 4 - Cornell Plates Briefing (PDF File)

Lab 4 - centimeter / millimeter scale (PDF File)

Lab 3 Briefing Materials Available

Lab Safety (PDF File)

Lab 3 - Laser Beam Conditioning (PDF File)

Lab 3 Prep Package Available

Lab 3 Prep Package (PDF File)

In a nutshell:

1. Watch the Feynman videos (link inside package)
2. Read the worksheet section "Optical Physics - Models of Reality"
3. Do the problems under "Fundamental Idea of Optics Image Formation"
4. Demonstrate preparedness at the beginning of Lab 3

Lab 2 Materials Available

"Optical Table Fundamentals and Component Placement"

Lab 2 Materials (PDF File)

I'll try to post the lab materials prior to each class.  These are the slides I brief in the pre-lab session in BioSci 245.

Often they contain exercises and procedures that we'll follow in the lab.   I will have the file up on the lab computer for you to refer to during lab.  If you bring your laptop to lab you could use that.

These can go in your lab notebook as well, and will give you a single place where all your lab material is so you don't have to rely on an internet connection.  If you are printing them out, they'll fit 4 or 6 slides to a page and still be readable.

Lab 2 - Prep Package Available

Lab 2 - Prep Package (PDF File)

Instructions:  download and complete the lab prep package.  You may work in groups.  In fact I prefer that you do as it is more effective.  Print out and include the package and record answers in your lab notebook - that's a best practice.  At the beginning of class for Lab 2 we'll go around the room giving everyone a 30-second chance to demonstrate preparedness.  The way this works is I randomly choose an item from the package and ask you to start talking about your answer.  At the end of 30 seconds I call for a vote from the class:  "Prepared or not prepared?"  Amazingly, everyone can tell within 30 seconds if you done your prep.  I use this technique instead of written work because, first of all, it closely mimics how team-mates in a research lab will evaluate your preparedness, secondly it uses peer pressure instead of a grade which is effective psychology, and thirdly, it is much less work for me.  Plus everyone really gets into yelling "Prepared" (which you will be).

Lab 1 - Intro to 492

Materials presented in class:

     Physics 492 Info (PDF File)

     Lab 1 - Intro to Physics 492 (PDF file)

     Lab 1 - Self Assessment (PDF File)

We're off to a good start, almost too good with 15 students attending the first session.  For those of you who are not yet registered, just a reminder to get that taken care of soonest.  At some point you'll need to do extra paperwork to add, so why wait until then?

Aside from the long intro lecture, the remainder of the course will follow the same general pattern established in the first class.  We'll meet in BioSci 245 for maybe half an hour, forty-five minutes first.  There we'll go over the plan for the day, demonstrate preparedness, have a quick lecture, and do a Quantum Snippet.  The Quantum Snippets are bite-sized pieces of quantum mechanics that prepare us for a theoretical understanding of future lab results.

Our Quantum Snippet today was on the mathematics of QM, introducing the idea of linear vector spaces.  The mathematics of QM is the mathematics of linear vector spaces, very different from the mathematics of classical mechanics and electromagnetism.  I went over a couple of the key aspects of linear vector spaces, which were the closure relations (first 2 properties below).  There are other aspects too, likely very familiar to you.  Here's the whole set:

Quantum Snippet:  Linear Vector Spaces

Let S be a set of things T and let addition and scalar multiplication be defined on S.  Then S is a linear vector space if the following hold:

     For all T1 and T2 in S, T1 + T2 is also an element of S

     For all T1 in S, and scalars a, aT1 is also an element of S

And additionally,

     T1 + T2 = T2 + T1

       (T1 + T2) + T3 = T1 + (T2 + T3)

     T1 + 0 = T1 for some element 0 in S

       There is a -T1 in S for every T1 in S such that T1 + (-T1) = 0

     a(T1 + T2) = aT1 + aT2 

     (a+b)T1 = aT1 + bT1

       (ab)T1 = a(bT1)

     1T1 = T1

This last set of properties should be familiar as the common rules of arithmetic when T are the real numbers and the addition and multiplication operations are the familiar ones.  Since the real numbers are in fact closed under these rules of addition and multiplication, they form a linear vector space.  It is instructive to think about some things that are and are not linear vector spaces.  A good place to start is this page giving examples and exercises.

After the Snippet, which will be a general feature of the first part of class, we went across the way to the lab where Professor Terebey gave a short safety and lab rules briefing.  Then we turned on the laser...

Young's double slit experiment

... which generated this fringe pattern after passing through a double slit on the glass Cornell plate.  These fringes are an example of interference.  Interference will be a strong theme throughout the course.


I took this photo with my cell phone.  Cell phones are great gadgets for recording experiments: setups, data, screenshots, interference patterns, group photos, what-not.  Get in the habit.

A note about class/lab hours.  This is a 3-credit class, which means you are expected to spend 9-12 hours a week in and out of class/lab combined per week.  The formal class hours are just under 3 hours a week, so that means there will be a substantial time commitment outside those hours.  I will generally hold the lab open for an extra hour (or more) and encourage you to use that time.  It will be the most convenient.  I will also hold the lab open by arrangement for a few hours on alternate Fridays, starting October 5.  You will absolutely need to use most of these times to complete your lab work so you should plan to do so.  You will also need a comparable amount of time for lab prep, organizing your lab notebook, doing reading & research, and putting together your final presentation.  Be sure to budget this time.

Just a reminder to be sure to download the Lab 2 prep package (next post) and complete it before we meet again.  We'll do the prepared/not-prepared check where you each get 30 seconds to demonstrate preparedness.

And thanks to those who've already sent me an email.  You've given me a good start on the class email list.

Physics 492 Again!

Physics 492 Advanced Optics Lab is offered again during the Fall 2012 quarter at Cal State LA. We will be meeting at 6:30 PM Mondays and Wednesdays. The class is an opportunity to get some hands-on and in-depth experience with photon-based quantum mechanical systems in a typical optics lab environment. Photons are easily generated, manipulated, and detected with simple apparatus. Among other topics, we will explore the physics of quantum interference and superposition in the two state system as we build various interferometers and poke at them with polarization probes.

I've structured the class so participants can develop important lab skills: lab safety, preparation, experiment planning, design and fabrication of apparatus, equipment handling, working in teams and individually, keeping a notebook, and presenting results. Grades are based in part on preparation, demonstrated lab skills, lab notebook quality, and a 10-minute presentation in lieu of a final exam. Grading thus mimics evaluation that occurs in an academic or industrial lab. There are no graded exams, quizzes or formal lab writeups.

Class will meet twice weekly in a brand new facility with plenty of workspace. Lab will be open after class for individual and team work on projects. Available equipment includes an optical table, laser source, beam expander, lenses, mirrors, ccd detector, desktop PC, beamsplitters, polarizing filters and various opto-mechanical components for locating and positioning optics on the table.

While there are no formal prerequisites, students are typically upper division and masters students familiar with optics at the freshman physics level (simple raytracing), the solution to the free-space wave equation ("e to the i omega t"), and math with 2x2 matrices (linear algebra). If interested in taking the class you should sign up as early as possible as there are a limited number of seats.