Modern Optics Lab

Modern Optics Lab

Introductory Meeting

Modern Optics Lab

Contact InformationLab Organization:Gernot LaicherSouth Physics 410801-585-5553gernot@physics.utah.edu

Teaching Assistant (Sections 3411-001 and 003):Ilya Reznik801-706-6057 (cell) ilyareznik@gmail.comOffice hours: Mondays 5:00 p.m. – 6:00 p.m. in South Physics room 405

Lab Attendant (Section 3411-002):Prof. Adam Boltonbolton@physics.utah.edu468 INSCC

TA (Section 3411-004):Anil Ghimireanghimire@hotmail.com

Website: http://www.physics.utah.edu/~gernot/Modern Optics/Modern Optics.html

Modern Optics Lab

Lab Format• Lab descriptions will be available on our website in pdf format.

Prepare yourself before coming to the lab (know the physics, read through the lab description and understand the principle of the experiment and the data evaluation methods). Think about the format of your lab report before coming to class. Writing a brief outline of how your lab report will be organized will make it much easier to produce a good lab report.

• Labs are done individually (no groups).

• TA will give a short introduction/overview to the lab activity at the beginning of the lab.

• Lab report is written during the lab activity and must be submitted at the end of the 4 hour lab period.

• 10 experiments are performed over the course of the class. - 9 are the same for everyone. - In lab 10 you can choose one of 4 possible activities.

Modern Optics Lab

Grading in Modern Optics• Homework: 25%• Lab: 35%• Exams: 40%

• Your lab score is obtained as follows:90%: Grade received for lab reports10%: 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

Modern Optics Lab

The Lab Report Grade / Format• General guideline (may vary somewhat depending on lab activity and

TA):20% Objective

- Sketch- Description of setup- Method

30% Record of raw data 30% Evaluation of data

- Calculations- Discussion- Conclusion

10% Error calculation- Measurement uncertainties in raw data- Propagation of error

10% General appearance- Legible ?- Looks organized ?- Consistent format ?- Easy to follow ?

Modern Optics Lab

Late Completion

• If you run out of time before completing the lab:

Talk to the TA, see whether he can arrange extra lab time on T,W,H, or F (Mondays generally not available) to complete an activity.

There is no guarantee that such extra lab time can be granted.

The TA may set a limit on how much extra time may be given to any one student over the semester. (General guideline: For no more than on two lab activities can extra time be requested).

• Late completions generally result in an automatic 15% reduction in the lab report grade (exception: illness, etc.).

Modern Optics Lab

Missing a lab due to Illness, etc.• Arrange with the TA a way to make up the

missed lab activity.- If possible, the TA can allow you to attend another section.- If possible, a time outside the regular lab hours may be arranged.- In worst case scenarios, we may waive a lab and base your grade on the remaining average.

You cannot expect to be allowed to make up a lab activity without penalty unless you have a very good reason (illness, etc.).(Skiing or your brother’s birthday doesn’t count)

Modern Optics Lab

Sample Lab Report Pages

Modern Optics Lab

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.

cmx 4.08.5

Modern Optics Lab

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

deviation Standard

mean theofdeviation Standard

x

x

N

xx

Modern Optics Lab

Error Propagation

• Calculating the error in the final result based on the error in the measured quantity can be done in several ways.

a) Calculate the “high” and “low” possible outcome based on using extreme values of input data (x+x and x-x).

b) Doing a “proper” error calculation.

Modern Optics Lab

“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 f of the function f(x) at the point x=xo

oo xx

2xxf 3.05.2 ox

Modern Optics Lab

f(x)=x^2

0

5

10

15

0 1 2 3 4x

f(x)

ox

oo xx oo xx

oxf

oo xxf

oo xxf

Modern Optics Lab

f(x)=x^2

0

5

10

15

0 1 2 3 4x

f(x)

ox

ox2

oxf

oo xxf

oo xxf

oxf '

oo xfx '2

2'' ooooo xxfxxfxf

Modern Optics Lab

........xf

General Error Propagation Method

......),,(222

zz

fy

y

fx

x

fzyxf

..............,, zyxf

2

)(

xdx

dfxf

Modern Optics Lab

Example

6.04.27

4.02.34

03.052.1

sinsin

2

1

1

2211

n

nn

.....8565.1

4.27sin

2.34sin52.1

sin

sin

2

112

n

n

2

22

2

2

11

2

2

11

22

nnn

n

nn

582.34.27cos

4.27sin

2.34sin52.1cos

sin

sin

732.24.27sin

2.34cos52.1

sin

cos

221.14.27sin

2.34sin

sin

sin

222

211

2

2

2

11

1

2

2

1

1

2

nn

nn

n

n

Modern Optics Lab

Example

6.04.27

4.02.34

03.052.1

sinsin

2

1

1

2211

n

nn

.....8565.1

4.27sin

2.34sin52.1

sin

sin

2

112

n

n

06.86.1

056.0

1806.0582.3

1804.0732.203.0221.1

2

222

2

n

n

Modern Optics Lab

Example using “High/Low” Method

6.04.27

4.02.34

03.052.1

sinsin

2

1

1

2211

n

nn

09.02

766.1952.1

2

....766.10.28sin

8.33sin49.1

sin

sin

....952.18.26sin

6.34sin55.1

sin

sin

min,2max,22

22

1111min,2

22

1111max,2

nnn

nnn

nnn

09.86.12 n Method overestimateserror somewhat