Electro-Optics Program
Physics Department, San Diego State University
Professor Jeffrey Davis - Director
(619)-594-6158 - jdavis@sciences.sdsu.edu
The Electro-Optics option at SDSU provides students with a B.S. or M.S. degree in physics with an emphasis in Electro-Optics. The program has been in existence since the early 1960's and has achieved national recognition at both the undergraduate and M.S. levels. Because students obtain a B.S. or M.S. degree in Physics, they have all of the math and physics courses that are normally associated with these degrees. Note that SDSU does not offer a Ph.D. degree and consequently our B.S. and M.S. students can be assured of receiving all of our attention.
The Electro-Optics option program consists of two lecture courses, a lab and a thesis project. An introductory lecture course provides a comprehensive introduction to the field of optics while an advanced lecture course covers specialized topics including laser physics, optical pattern recognition, and nonlinear optics. The laboratory forms the basic strength of the program and serves several purposes. Our main goal is to introduce students to several important topics that contain a lot of physics and are important in the discipline. We also help develop the student's abilities to work independently. Finally, formal reports are required for each experiment, allowing students to perfect their technical writing skills. Finally, each student is required to do a thesis.
The experimental areas covered in the laboratory course include:
1) Polarization studies and Electro-optic Light Modulators - We examine ways of generating various polarization states and analyzing them using Jones Matrices. We examine various devices that allow the modulation of the polarization state including polarizers, quarter and half waveplates, a Soleil Babinet Compensator and an electro-optic light modulator. We also study optically active and magneto-optic materials that rotate the plane of polarization of linearly polarized light clockwise or counterclockwise.
2) Acousto-optic Light Modulators - A diffraction grating can be generated in a piece of glass by sending a sound wave through it. This diffraction grating will deflect a laser beam by an angle that is proportional to the frequency of sound. The intensity of the diffracted beam is proportional to the driving voltage that generates the sound wave. We study the physics of this device and apply it to optical signal processing.
3) Fiber optics - We analyze the principles of optical fiber communication systems including the numerical aperture and absorption of the fiber. Then we examine the pulse dispersion of the fiber - when an extremely short pulse enters into the fiber, it emerges broadened in time. We investigate the various causes for this including the fiber, the detector, and the measuring equipment. We also examine the solutions of the wave equation within a fiber waveguide.
4) Laser Physics - We examine the physics of a helium neon laser. We measure the single pass gain. We study the confocal scanning Fabry Perot interferometer and use it to examine the resonance frequencies of the laser modes for hemiconfocal and confocal laser cavities. We introduce a wire into the laser cavity. By adjusting the position of the wire and by adjusting the mirror alignment, the students can force the laser to oscillate in different transverse modes. Students have found Hermite-Gaussian, Laguerre-Gaussian and even some Ince-Gaussian modes. We also use mirrors with different transmission values to study the optimal output power based on the gain and internal loss of the cavity. Finally we vary the output wavelength of a laser where the rear mirror has been replaced with a prism.
5) Holography - We set up the optical system for making holograms emphasizing the coherence length of the laser and spatial filters. Then we expose and develop the film, and analyze the resulting images that result from the hologram. We then modify the sizes and positions of the orthoscopic and pseudoscopic images from the holograms by changing the radius of curvature of the reconstruction beam. Both transmission and reflection holograms are made.
6) Optical Image Processing and Optical Pattern Recognition - In optical image processing, the Fraunhofer diffraction pattern of an object in an input plane is formed. A second optical system forms another Fraunhofer diffraction pattern forming an image of the input object. We examine the effects of Abbe-Porter spatial filtering in the Fourier plane. The resulting image in the output plane is altered - for example the edges of the object can be enhanced. In the second part of the experiment, we place a specially made hologram in the Fourier plane. If it is made correctly, we will have a bright correlation spot in the output plane when a desired object is placed in the input plane.
7) Fourier Transform Spectroscopy with a Michelson Interferometer - We analyze the interference pattern created by the Michelson Interferometer and examine the spectral output of various light sources. We use a computer system to perform the Fourier transform of the output of the Interferometer.
8) Erbium doped optical fiber amplifiers - We study erbium doped optical fiber amplifiers. This experiment includes a pump laser at 980 nm, a tunable probe laser in the 1500 nm region, an ASE source, and an optical spectrum analyzer. We examine the properties of various lengths of erbium-doped optical fiber, as well as the effects of optical fiber couplers, splitters, and WDM splitters. We also study optical isolators, tunable filters, and fiber Bragg gratings. Finally we combine these various components to construct all fiber lasers.
9) Multilayer dielectric optical coatings or photonic crystals — Multilayer dielectric optical coatings and photonic crystals are made by forming layers in 1,2, or 3 dimensions of different materials having different indices of refraction. These can be simulated in the RF frequency region by using sequences of 50 and 75-ohm coax cables representing L and H layers. Various experiments are performed including mirror structures, Fabry Perot interferometers, and structures that show superluminal light transmission.
10) Diffractive optics - We have a LCD that is set up to operate in a binary phase mode where each pixel has a phase value of 0 or pi radians. Students can easily program diffraction gratings, lenses, or other diffractive optics onto the LCD and gain a greater understanding of Fourier optics.
Individual Thesis Research
Each student at either the B.S. or M.S. level is required to do an individual thesis research project lasting a full year. These projects allow students to experience the difficulties commonly faced in advanced research and engineering situations and allow them to assume responsible positions more quickly after graduation. These are high quality projects and have produced over 100 student/faculty co-authored publications. Current research projects include programmable holograms and optical elements, image processing with an acousto-optic light modulator, the physics of spatial light modulators, tunable laser diodes, and ultrafast lasers. Publications with student coauthors can be found on the publications list on the website of Jeffrey Davis.
All research students participate in a seminar in which they give lectures on their projects to other members of the group. This not only allows the other students to learn about the research, but also provides each student with valuable experience in oral presentations of technical material.
The research/teaching facilities occupy seven laboratories and include a number of vibration isolation tables, numerous lasers, detectors, instrumentation, and electro-optic devices.
Faculty
The Director of the Electro-Optics and Lasers Program is Professor Jeffrey A. Davis. Professor Davis is a Fellow of both the Optical Society of America and of SPIE. Other faculty members include Professors Matt Anderson, and Richard Morris. Don Cottrell is officially retired, but is extremely active and collaborating with Jeff Davis. Roger Lilly was a valuable member of this program, but has since retired.
Success of the program
The Electro-Optics program has been extremely successful by any measure. Companies ranging from the larger aerospace companies and government laboratories to small start-up companies have hired our graduates. Many students have obtained Ph.D. degrees at a number of institutions in Physics, Applied Physics, Optics, Electrical Engineering, Biophysics, Oceanography and even Psychology. In all cases, the laboratory expertise of the students is a primary attraction. Our graduates include the first Hispanic NASA Astronaut and the Chief Technology Officer of a major optics company.
The program receives excellent external support from a number of companies including equipment, supplies, and cash. This support allows us to offer this type of high quality educational program. In addition, these companies routinely call requesting students for employment.
The job market in Electro-Optics has always been strong. Our track record over the past 35 years continues to help our students find employment opportunities.
Resources for students
Professional Societies — these organizations offer student member rates and monthly magazines
a) Optical Society of America - http://www.osa.org/
b) SPIE-The International society for Optical Engineering - http://www.spie.org/
c) American Physical Society - http://www.aps.org/
d) American Institute of Physics — http://www.aip.org/
Career Information — these web sites show job information
https://www.aps.org/careers/employment/index.cfm This is run by American Physical Society
http://www.aip.org/careersvc This is run by the American Institute of Physics
http://www.osa.org/employ/ This is operated by the Optical Society of America
http://spieworks.com/employment/ This is operated by SPIE
http://www.photonicsjobs.com/ This is run by one of the trade magazines
http://www.photonics.com/employment/XQ/ASP/QX/index.html This is run by one of the trade magazine
Mentoring — these web sites offer mentoring for Women in the Sciences.
a) http://www.spie.org/wio/home.html This is operated by SPIE
b) http://www.osa.org/wosa/ This is operated by OSA
Please click here for a list of the Publications of Jeff Davis, including identification of student coauthors
Please click here to go to the Physics Department Homepage