PHTN1300
Principles of Light Sources and Lasers

(PROTOTYPE 2010 Fall)

Course Description

This course begins with a look at various incoherent light sources including blackbody radiation and atomic processes governing light production. An introduction to spectroscopic techniques and quantum mechanics is provided. The majority of the course is dedicated to the fundamental operating principles of lasers including the quantum processes involved (with basic rate equations), the concept of laser gain and loss, excitation (pump) mechanisms, and optical resonators. Emphasis will be placed on use of the threshold gain equation, including situations with intra-cavity losses. An intensive laboratory component allows students to explore course material in a practical hands-on manner.

One of our lab lasers, a Coherent Innova-90 argon ion, is seen here with the output beam split into it's components by a diffraction grating. Argon lasers have ten visible lasing transitions in the green, blue, and violet regions - six are seen here including the powerful lines at 488.0 nm and 514.5 nm.

Prerequisites

This course is a prerequisite for PHTN1400 and PHTN1432

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This course is offered as part of the Photonics Engineering Technician (2 year) and Photonics Engineering Technologist (3 year) Programs at Niagara College.

Evaluation ...

Two midterm examinations valued at 15% each

These midterm tests primarily evaluate fundamental concepts of light emission and lasers. (e.g. expect questions of the nature "solve for xxxx given parameters yyyy). Questions pertaining to knowledge gained during lab assignments will also be incorporated into the tests (e.g. calculating wavelengths using a spectroscope, etc).
Midterm #1 during week 6 in class
One Hour, in class. Covering Blackbody concepts, atomic emission, spectroscopy, semiconductors, and quantum mechanics concepts (Chapters 1, 2, and 3)
Review held in class
Midterm #2 during week 11 in class
One Hour, in class. Covering laser gain and transitions (Chapter 4 and beginning of chapter 5)
Review held in class

One final test valued at 30%

This test will feature applications of fundamentals (e.g. do not expect questions testing 'pure theory' such as the first two tests, rather expect concepts such as blackbody radiation to be applied to a practical problem such as determination of required laser gain). It is not an "all encompassing" final exam but rather a demonstration of application of learned theory.
Final Test during week 14 in class
Two Hours, in lab period. Covering applications of theory to real-world problems involving lasers (primarily using gain/loss concepts to develop basic models and predict operating parameters)

Labs and assignments combined for a total of 40%

Check your marks here (when loaded in late September)

NOTE: Late Labs and Assignments are penalized at the rate of -10% per day late and receive a mark of 0% after five days late. All labs and assignments must be received by the end of term, regardless of the fact they may receive a mark of zero from being late, or a failure in the course will result. See the CIS (available via Blackboard) for full details of course evaluation policies.

Textbook

Fundamentals of Light Sources and Lasers

Chapters 1 to 5 and 9 are covered in this course. The rest of the text is covered in the next course

Course Notes

NIST eBook of Atomic Spectral Data as required for several labs in this course
Hyperphysics by C.R. Nave ...a complete Web-based physics reference
Notes On Lab Reports details what is required for a lab report in this course
Notes On Lab Reports II with an advanced discussion on both formal and informal lab reports
Quantum Mechanics Primer from the Homebuilt Lasers Site (opens in a new window)
Photomultiplier Tubes the basic operation of these tubes as required for lab 3 (opens in a new window)
Using a Spectroscope the basic theory and use of the spectroscopes in our lab
Spectroscopes a reference on using a spectroscope as required for Labs 1 and 2 (Password-protected PDF)

Equipment Manuals and SOPs

Standard Operating Procedures (SOPs) for laboratory equipment.

Lecture Schedule (Planned)

Laboratories and Assignments

There are five labs plus one assignment in this course. Lab sessions are two-hours in length and individual labs can span up to three consecutive lab periods. Labs for this course emphasize both proficiency in manual skills required of a technician (e.g. the ability to use laboratory equipment, align optics and lasers, and take measurements of a system to characterize it) and experimental proof of concepts from the lectures. Reports will be submitted for each lab with an emphasis on results and observations.

The number one reason for failure of the lab portion of this course is submission of incomplete or late labs. Read the lab carefully and ensure all points listed are addressed (many require independent research). As well, submit labs on time: if a lab which would normally garner a respectable mark of 70% is submitted three days late the mark earned is only 49% - a failing grade! Failure to submit a lab, or submission of more than one late lab, will result in the student being placed on course condition.

NOTE: While observed results (numbers only) may be identical for more than one student, no other portions of the lab are to be shared. Where procedures, analysis, graphs, and/or conclusions are suspected to be plagiarized, labs will be submitted to the dean's office and all students involved will receive a mark of zero. "Sharing" answers and analysis often equates to "Plagiarism" which is academic misconduct and will be treated accordingly.

Spectroscopy Labs:

Lab 1: Basic Spectroscopy
The emissions of various light sources are analyzed using two types of grating instruments. Emissions from broadband sources such as incandescent and fluorescent sources are first analyzed using a manual spectroscope (after a suitable calibration procedure). Atomic spectra from several pure gases in spectrum tubes (e.g. Hydrogen, Mercury, and Neon) are also analyzed and related to energy level transitions in the atomic species. Students will also be given an unknown spectral source (a spectrum tube with an unknown gas) and be required to identify the gas via its spectral emissions using a high-resolution computer-based Ocean Optics spectrograph.
Lab Weighting: 1.0
Part A&B on week 2; Part C&D on week 3
Full Lab Report due at the beginning of the lab on week 4
Lab 1 Marking Scheme example

Lab 2: Determining Planck's Constant
Using spectroscopy and basic electronics the spectral and V/I characteristics of several LEDs is observed. Analysis of the data allows determination of Planck's constant. Using the same technique, the unknown emission wavelength of an IR LED is determined soleley from electrical observations.
Lab Weighting: 1.0
Lab on week 4
Full Lab Report due at the beginning of the lab on week 5

Lab 3: Advanced Spectroscopy
A lab in which practical skills aimed at using various spectrometers will be developed and students will research the basic principles of these spectrometers. Students will use a manual (single beam) spectrometer in the first part of the lab (a Coleman-20) and both a Perkin-Elmer Lambda-3B dual-beam automated spectrograph in the second part of the lab. The operation of the single-beam, manual unit (Coleman-20) and the Dual-beam unit (Lambda 3B) will be compared, especially with respect to use of each for analytical processes.
Lab Weighting: 1.0
Lab on week 5
Condensed Lab Report (with questions) due on week 6

Laser Labs and Assignments:

Lab 4: HeNe Lasers
Basic electronics and laboratory skills will be developed while investigating the operation of the helium-neon gas laser. Students will wire a 'bare' gas laser tube to a power supply. As part of an assignment optical and electrical characteristics will be investigated and students will be introduced to application of the gain threshold equation.
Lab Weighting: 1.0
Lab on week 7
Condensed Lab Report (with questions) due on week 8

Assignment 1: Gain and Loss in Lasers
Complete the following questions from the text (pp. 113-114): 4.3 (a) and (b), 4.4, 4.7, 4.8, and 4.9
Notes:

4.3 - remember than population inversion does not imply enough gain to overcome losses and allow lasing

4.8 - calculate using both the method of example 4.9.2 (sum of percentages) as well as modifying the gain threshold equation to include the losses. This allows comparison of two models (one simple, one more complex). Be sure to outline both methods completely and on separate pages.

4.9 - Use the gain threshold equation to solve this problem. Use the attenuation figure quoted in the text, set the threshold gain (g_th) in the formula equal to the gain figure quoted (g₀), and solve for reflectivity of the OC.

show all work

"one electron making a transition through the bandgap leads to the production of one photon"

Lab Weighting: 1.0

Assignment Questions due at the beginning of the class on week 9

Lab 5: Gas Laser Optics
A bare helium-neon gas laser tube with completely external optics (the tube features windows instead of integral optics like most tubes) will be setup and the mechanics of this laser will be studied. The student will build the entire optical resonator on an optical breadboard and align cavity optics. Various electromagnetic modes (TEMxx) will be observed when aligning the optics. Next, gain will be determined (in the same manner as outlined in chapter 4 of Csele) by inserting a glass slide intra-cavity at various angles. This glass slide will render a loss ranging from close to 0% at Brewster's angle (polarized) to 8% at perpendicular. Using a reformulated gain threshold equation, actual small-signal gain (g₀) for the amplification medium will be determined.
Lab Weighting: 2.0
Part A on week 9
Part B on week 10
Part C on week 11
Full Lab Report due at the beginning of the lab period on week 12
Lab 5 Marking Scheme example

Contacts:

For the Photonics Technician/Technology programs ...
Program Coordinator Jay Yatulis
Office: V14
Telephone (905) 735-2211 x.7633
E-Mail: (Be sure to include 'Photonics' in the subject line to avoid deletion by an anti-spam filter)

For this course ...
Professor Mark Csele
Office: Office: V13 (Office hours are POSTED on the EL panel on the door)
Telephone: (905) 735-2211 x.7629
E-Mail: (Be sure to include 'Lasers' in the subject line to avoid deletion by an anti-spam filter)
URL: http://technology.niagarac.on.ca/people/mcsele

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PHTN1300Principles of Light Sources and Lasers