PHY 442                             Optics Lab               Fall 2003/Sharma

 

Instructor: Natthi L. Sharma,   Office:  329 Strong Hall,    Phone:  (734) 487-8645

E-mail: phy_sharma@online.emich.edu

 

Optics has been a forerunner in the field of physics.  It is as old as Newtonian mechanics and yet young enough to keep surprising us with discoveries such as lasers, holography, optical phase conjugation, squeezed states of light, laser cooling, optical fibers and solutions.  In this laboratory course you will study some optical phenomena in geometrical (ray) and physical (wave) optics and also acquaint yourself with the associated optical equipment.  As in any other lab, you will also learn how to collect data, analyze it, and finally report your results.  Experimentation is the foundation of scientific knowledge.  So make sure you understand what you are doing during your lab work.

 

The course comprises six (6) labs.  There are usually twelve to thirteen lab meetings, each of three hours every week.  Each lab will have two lab meetings to be completed. There will be no lab on the first and the last week of classes.  As some of the material may not have been covered in the lecture course yet, you are supposed to read about the theory and come prepared for the experiment assigned to you.  This will help you understand what is going on rather than just doing the experiment mechanically.

 

A report on the previous lab will be due before you could start the next lab.  Grade-point distribution for each part of a lab report is as follows:

 

1. Title and objective (0.25 point)

2. A brief theory, explaining each symbol in the equations (1 point)

3. A sketch of each part of the experiment (1.25)

4. Data for each part of the experiment with instrumental uncertainties (2.5)

5. Data analysis -- calculations and graphs (2.5)

6. Results with graphs and discussion relating to sources of errors (1.5)

7. Other relevant material such as answers to questions and legibility if hand written (1).

This is a tentative distribution of grade points, it may change somewhat from lab to lab.

 

If you need to do something of your interest or something more challenging, let me know.  There is always some room for new development or substitution.

 

 

Things to Remember:

 

1) You should never look into a direct or a reflected laser beam.

 

2) Do not touch coated optical surfaces.  Your body oil damages the coating.

 

3) When you have completed your experiment, restore all the pieces of equipment properly and leave your table clean for the next group.

 

4) Before you leave get your lab assignment for the next week.

 

 

 

 

 

 

List of Experiments (6 out of the following 9):

 

1. Thin Lens: Focal length of a convergent lens by (a) autocollimation (b) lens formula and (c) displacement method, index of refraction of lens material with a spherometer, and focal length of a divergent lens.

 

2. Prism Spectrometer: Minimum deviation set-up, plot of the dispersion curve (n vs. l curve) for the prism material, and the determination of unknown wavelength (Hg green line).

Comparison of prism and grating spectra. Wavelengths of the spectral lines for the dispersion curve may be determined by using a monochromator in the modern optics lab.

 

 

3. Cardinal points: Location of focal, principal, and nodal points of two thin lens system separated by a distance d and verification of the relation P = P1 + P2 - d P1 P2  and the lens formula as applied to a thick lens.

 

 

4. Michelson Interferometer: Circular fringes, wavelength of laser light, and refractive index of air and glass. You should also use the interferometer in the Fabri-Perot mode to determine the wavelength difference between sodium doublet D1 and D2.

 

 

5. Diffraction

Single slit --- Intensity distribution (3 slits of different width) curves

Double slit --- Intensity distribution curve and comparison with theory

Multiple slits and grating-- Observe the number (2a/b-1) of principal interference maxima

inside the central diffraction peak, and the number (N-2) of secondary maxima between

successive principal maxima. Observe that in a grating (N v. large) secondary maxima disappear and principal maxima become very bright ( N2 ) and sharp.

Observe diffraction from circular obstacle (Poisson spot), zone plate etc.

 

 

6. Polarization and Optical activity: The law of Malus, transmission axis, cross polarizers, wave plates, circular polarization, and optical activity (rotation of plane of polarization) in sugar solution.

You should plot reflectivity versus angle of incidence curve for light polarized parallel to the plane of incidence and find the Brewster’s angle from this curve.

 

 

7. Microwave Optics: Study of reflection, standing waves, polarization, interference, and diffraction of microwaves.

 

8. Speed of light: Rotating mirror method, if not done in the modern physics lab.

 

9. A Study of Lens Aberrations:

Observe and record chromatic aberration in a lens.

Observe and record spherical aberration, coma, astigmatism, and distortion in the images formed by non-paraxial rays in lenses and mirrors.

Compare spherical aberration and coma in two lenses of same focal length but different shapes (one plano-convex and the other concavo-convex).