1. Modern Optics Lab Introductory Meeting

2. Contact Information
Gernot Laicher
South Physics 410
(801)
TAs: Bijaya Thapa (Tuesday and Wednesday Sections)
Jieying (Amaya) Mao (Thursday and Friday Sections)
Website:
Optics/Modern Optics.html
Modern Optics Lab

3. Lab Format Lab descriptions will be on our website (pdf files).
Before the lab:
Read through lab description.
Try to understand the principle of the experiment and the data evaluation methods.
Think about the format of your lab report.
Labs are done individually, not in groups.
A short introduction/overview to the lab activity is usually given at the beginning of the lab.
Lab report is written as much as possible during the lab. Submission deadline is 1 week after lab completion.
9 labs (11 lab sessions) are planned over the course of the class (may vary).
Modern Optics Lab

4. Grading in Modern Optics
Quizzes: 15%
Midterm Exams: 20%
Final Exam: 30%
Lab Grade: 35%
Your lab score is obtained as follows:
90%: Grade received for lab reports
10%: General Lab conduct
Displayed interest/diligence in lab activity
Ability to answer questions asked by TA
Cleanliness of workspace at the end of the lab
Creativity
Punctuality
There is a 10% grade deduction for every day the lab report is late.
Modern Optics Lab

5. Writing the Lab Report
Keep in mind the main purpose of a lab report which is a written record of the
purpose of the lab activity,
methods and techniques - experimentally and mathematically,
raw data as measured and their uncertainties,
data analysis (e.g., computations) including error propagation,
conclusions derived from your data analysis.
“Say what needs to be said” as efficiently, concise, and clear as possible – we are not writing novels.
A picture is worth a thousand words:
Include a sketch of the apparatus when describing the methods.
Label what’s on the sketch.
Don’t forget units!
Don’t submit messy lab reports in which the TA needs to “fish for information”.
Modern Optics Lab

6. Lab Report Grading
General guideline (may vary depending on lab activity and TA):
20% Purpose, Methods, Techniques …..
30% Raw Data Record
20% Data Analysis
10% Error calculation
Measurement uncertainties in raw data
Propagation of error
20% General appearance and organization
Legible ?
Looks organized ?
Easy to follow ?
Modern Optics Lab

7. Missing a lab due to Illness, etc.
Arrange with the TA a way to make up the missed lab activity.
If possible, in another section the same week.
Alternatively a time outside the regular lab hours may be arranged between you and TA.
Worst case: We may waive a lab and base your grade on the remaining average.
Modern Optics Lab

8. Significant Figures and Uncertainty
Report uncertainties (error) in measurements to one significant digit
Make sure the position of the least significant digit of the measured value agrees with that of the uncertainty.
Modern Optics Lab

9. Estimating and Reporting Uncertainty
Estimation of uncertainty from a single measurement due to measuring device (e.g., ability to read out a scale)
Uncertainty in repeated measurements and averaging (averaging 5 or more measurements to get mean)
 calculate standard deviation of the mean
Modern Optics Lab

10. Error Propagation
Calculating the error in the final result based on the error in the measured quantity can be done in several ways.
Calculate the “high” and “low” possible outcome based on using extreme values of input data (x+dx and x-dx).
Doing a “proper” error calculation.
Modern Optics Lab

11. “High/Low” Method Suppose you measure a quantity and it’s uncertainty
….and you want to calculate the value of a function f(x) and the uncertainty df of the function f(x) at the point x=xo
Modern Optics Lab

12. Modern Optics Lab

13. Modern Optics Lab

14. General Error Propagation Method
Modern Optics Lab

15. Example
Modern Optics Lab

16. Example
Modern Optics Lab

17. Example using “High/Low” Method
Method overestimates
error somewhat
Modern Optics Lab