PHTN1500: Advanced Laser Theory
In this course, students will mathematically model laser systems and processes with an emphasis of application of models to real-world lasers. Beginning with a pass-by-pass model, several approaches will be taken to improve accuracy when applied to high-gain lasers including the treatment of laser amplifiers as multiple segments. Comparison will then be made to the "gold standard" Rigrod model (which will be developed in lectures) and the Rigrod model will be adapted to handle real losses.
The effects of temperature on both diode and solid-state media will be investigated and application made to the design of DPSS systems (a convolution model being used to predict the effects of diode temperature drift on ultimate output power of the system). As well, thermalization of the LLL of quasi-three-level media will be investigated as re-absorption loss is considered (including such effects as Stark splitting of the LLL which occurs in most real solid-state media). Implications to laser design (e.g. end-pumping) will then be considered.
For pulsed (i.e. flashlamp pumped) lasers, models will be developed predicting the growth and decay of inversion as a function of time allowing determination of optimal parameters for Q-switching. Passive Q-switches will be examined including the effect of Excited State Absorption (ESA) which limits performance of these switches.
A model will then be presented from Laser Modeling predicting the output power as a function of inversion in a solid-state laser - this model will then be used with double-pulse lasers as an example application as well as with the First Pulse suppression (FPS) scheme to predict pulse power (as well as control the magnitude of this pulse through control of the switch transmision).
Many models will use numerical methods and will utilize spreadsheets. The goal is application of theoretical models to real lasers and so a substantial lab component allows students can examine application of, and prove, various models developed in the course on a variety of lasers.
It is required that you have obtained credit in PHTN1400 Principles of Laser Systems to enter this course. A mark of over 70% is highly recommended in the prerequisite course. Due to the mathematical rigor of this course, a strong understanding of mathematics is required for success in this course since both algebra and calculus are used extensively.
This course is offered as part of the Photonics Engineering Technology (3 year) Program at Niagara College.
Three midterm examinations, totalling 60%, as follows ...
Term test #1 on Monday, Oct. 17th in class (Moved due to Thanksgiving holiday)
50 minutes, in class, worth 20%. Covers the Pass-by-pass model, the Rigrod approach (with application to real lasers), and diode laser threshold models.
Term test #2 on Monday, Nov. 14th in class
50 minutes, in class, worth 20%. Covers quasi-three-level lasers, Stark splitting of levels, and the convolution model for predicting the effect of pump wavelength drift.
Term test #3 on Monday, Dec. 5th in class
50 minutes, in class, worth 20%. Covers Q-switched lasers, the inversion model, passive switches (including ESA), and the power model and applications (including double-pulse lasers and FPS).
Labs and assignments combined for a total of 40%
Course Policies ...
Course policies follow the Standardized Policies and Procedures for CEE (dated January 2011). In summary:
- LATE assignments are worth ZERO. There is no "grace period" with a "per day" penalty. Late submissions (i.e. ANY not printed and ready when you enter the lab) receive a mark of zero. You will be DENIED access to the printer at the start of the lab - either the lab is ready to submit, or it is late and hence worth zero.
- Students are allowed only ONE single-day late submission without penalty. This is a once only one-day extension ... once used, any further late submission will receive an automatic zero.
(This policy reflects expectations in the real world: to be late for work, once, will likely not result in termination however chronic late arrivals will almost certainly result in job loss. Develop good work ethic _now_.)
- Students must pass the theory (testing) and practical (lab/assignment) portions of the course separately in order to receive a passing grade. If a failing grade is received in either portion, then the lower of the two marks (theory or practical) will become the final grade.
- In order to be considered for supplementary evaluation (SE) upon failure in this course, a mark of 50% minimum will be required in the practical (lab/assignment) portion of the course plus a mark of 45% minimum in the theory (testing) portion. A theory mark of 44% or less, or a lab mark of 49% or less, will result in failure with no SE option.
- Granting of an SE is not automatic - those qualifying for an SE must apply to the chair who will arrange for the SE (since staff must be assigned to deliver the SE). Attendance and lab performance will be considered.
- Devices capable of RF reception are specifically banned during all examinations and tests. This includes cell phones (which are not permitted, whether turned on or not) as well as tablets and laptops. Scientific calculators must not have RF capability (i.e. the use of a cell phone, tablet, or laptop as a calculator is expressly forbidden even if the "wireless" function is switched off). Translational references and dictionaries must be in paper form, not on an electronic device.
Complete course policies can be found in the Teaching and Learning Plan (T&LP) document found on Blackboard.
Laser Modeling: A Numerical Approach with Algebra and Calculus by Csele, 2014, CRC Press, ISBN 9781466582507
The text, and the models presented within it, will be used extensively in this course including the Pass-by-pass model (chapter 3), Rigrod approach (chapter 4), Quasi-three-level lasers and Stark splitting (chapter 5), Convolution model (chapter 5), and models for inversions in Q-switched lasers (chapter 6).
Course Notes and References
There are several labs and assignments in this course. Lab sessions are two-hours in length.
In line with departmental policies, the lab/assignment portion of this course MUST be passed SEPARATELY from the theory portion in order to pass this course. Late labs result in an immediate mark of ZERO with no exceptions and no excuses accepted (including the now infamous "my printer ran out of ink" and "my computer died"). Failure to submit a lab (and a late lab is considered failed and will receive a mark of zero) will result in the student being placed on course condition. Failure to submit a second lab results in immediate EXPULSION from the course.
Assignment 1: Modeling Laser Diodes
Several models from the text are applied to semiconductor laser diode including predictions of threshold current, application of the pass-by-pass model to high gain lasers, and several models to predict output power including the Rigrod model.
Assignment due at the beginning of the lecture period (2016/09/26). Failure to submit this lab BEFORE or ON the due date and time will result in an immediate ZERO on the lab and placing of the student on course condition (meaning one more late or missing lab or assignment results in immediate EXPULSION from the course without recourse).
Lab 1: Modeling a Fiber Laser
In this lab, which will tie together concepts from various courses in the program, key parameters of an Erbium-Doped Fiber Laser (EDFL) will be determined in the lab including loss of system elements and saturation parameters of the amplifier. Determined parameters will then be applied to predict laser performance using several models including the Rigrod model.
Labs on week 4 (Week starting 2016/09/26) in V15 - No two-hour lecture this week
Lab Report due at the beginning of the lab period on the following week (beginning 2016/10/03) for each section - Tuesday labs are due at the beginning of class on Tuesday, etc. Failure to submit this lab BEFORE or ON the due date and time will result in an immediate ZERO on the lab and placing of the student on course condition (meaning one more late or missing lab results in immediate EXPULSION from the course without recourse).
Assignment 2: Thermal Effects on Pump Diodes
Following the models in chapter 5 of Laser Modeling
employing the technique of convolution, the effects of pump diode wavelength drift on DPSS output (observed in PHTN1400) are modeled mathematically and applied to the optimization of a commercial DPSS laser.
Assignment due at the beginning of the lecture period (2016/10/31). Failure to submit this assignment BEFORE or ON the due date and time will result in an immediate ZERO on the lab and placing of the student on course condition (meaning one more late or missing lab or assignment results in immediate EXPULSION from the course without recourse).
Lab 2: Re-Absorption Loss in a DPSS System
Re-absorption loss of the 946nm quasi-three-level transitions in Nd:YAG will be accurately computed and applied to predictions of threshold pump power for a commercial laser based on the temperature of the amplifier. Specific attention will be paid to Stark levels, and saturation effects of the LLL thermal population will be examined.
Lab on week 9 (Week Starting 2016/10/31) in V15 - No two-hour lecture this week
PRELAB (worth 25%) due on entry to the lab period
Lab Report due at the beginning of the lab period on the following week (2016/11/07). Failure to submit this lab BEFORE or ON the due date and time will result in an immediate ZERO on the lab and placing of the student on course condition (meaning one more late or missing lab results in immediate EXPULSION from the course without recourse).
Lab 3: Modeling Q-Switched Lasers
Following section 6.8 of Laser Modeling
, by monitoring the flashlamp intensity of a solid-state YAG laser, a model is developed to predict the inversion, and hence the gain, as it develops in time taking into account both pumped population as well as spontaneous decay. Results of the model are compared to actual experimental results. In this manner, the optimal time to open the Q-switch may be predicted. The use of passive Q-switches will also be investigated.
Lab on week 11 (Week Starting 2016/11/14) in V15 - No two-hour lecture this week
PRELAB due on entry to the lab period
Lab Report due at the beginning of the lab period on the following week (2016/11/28).
The lab schedule is subject to change based on availability of laboratory equipment
For the Photonics Technician/Technology programs ...
Program Coordinator Alexander McGlashan
Telephone (905) 735-2211 x.7513
For this specific course ...
Professor Mark Csele
Office: V13A (Office hours are POSTED on the Electroluminescent panel on the office 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)
You are visitor # since June, 2009
Copyright (C) Professor M. Csele and Niagara College, Canada, 2009-2016
This course is part of the
Some images and text excerpted from Laser Modeling: A Numerical Approach with Algebra and Calculus by Csele, CRC Press, 2014, ISBN 9781466582507. Further reproduction in any form is prohibited without written approval from the publisher.