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Course Info | Class Notes | Evaluation / Check Marks | Labs

Course Description

PHTN9120 Lasers & Light Sources

Text ...

Evaluation ...

One term test valued at 20%
MIDTERM: in class (one hour) In Class on Monday March 11, 2013
• Basic gas physics and vacuum technology
• Gas Physics including use of gas laws, use of throughput/speed (Q, P, S) calculations
• Vacuum Technology including gauges (principles of operation, characteristics, limitations) and pumps (principles, characteristics, limits)
• Interpreting and using Mass Spectrometers
• System operation procedures (use of pumps, valves, and gauges in a system)
• Leak testing techniques
• Three supplementary PDFs (Gauges-Supplementary, Ion Gauges, Q and S of Pumps)
• All material from labs 1 through 3

One final test valued at 40%
FINAL TEST: in class (two hours) In Class on Monday April 15, 2013
• Deposition technology/techniques and Optical design
• Thermal evaporation technique: rates, materials, techniques (use of shutters, etc)
• Use of a thickness monitor
• Calculation of tooling factor, analysis of resulting spectra
• Sputtering technique: RF and DC targets, reactive sputtering, mass flow control
• Material from labs #4, 5

Check your Registration Status, Marks, and Lab Group Assignments here.

The Physics of Gases and Vacuum Systems

* The fundamental nature of gases and gas flow
* Gas Laws (e.g. Boyles Law) and applications
* The concept of vapour pressure and how it applies to gases, liquids, and solids
* The concept of conductance in a vacuum system
* Why a high vacuum is required (i.e. Mean Free Path)
* Purity in vacuum systems (including residual gas analysis)

* Operational principles of various mechanical pumps as well as limitations
* Operation of high vacuum pumps such as oil diffusion pumps
* Backstreaming and cryotrapping of diffusion pumps
* Principles of UHV pumps such as ion and getter pumps
* Measuring vacuum pressures using various gauges (e.g. pirani, ion, etc.)
* Leak detection and RGA
* Design and operation of a practical vacuum system
* Construction of vacuum systems including materials and couplings
* Identify sources of contamination and leaks in a typical vacuum system

* Evaporation Techniques (filaments, baskets, and boats)
* E-Beam Techniques and applications to optical materials
* Sputtering Techniques
* Calculating thickness using Point-Source Load Calculations from Nomograph
* Crystal Thickness Monitoring (In-Process)
* Operating a vacuum coating system

* Materials available for optics (reflectors, dielectrics)
* Physics of optics (e.g. principle of interference)
* Design of antireflective coatings
* Design of dielectric filters and mirrors

Laboratory work is a vital portion of this course. Whether experiencing first-hand the difficulties encountered while depositing thin films in a high-vacuum evaporator in the cleanroom (for example, controlling deposition rates manually on a thermal source and producing an accurate deposit thickness) or simply observing how an auto-ranging vacuum gauge operates in the spectroscopy lab, laboratory work provides hands-on skills not obtained from classroom work alone. Niagara is proud to have two unique dedicated lab spaces: the spectroscopy lab in V12 and the class-1000 cleanroom in V13C, both of which are utilized in this course.

As per departmental policy, late labs are assigned a mark of ZERO.

Lab1 - Gas Discharge Tubes
Using a turbomolecular high-vacuum system gas discharge tubes will be pumped. The effects of gas pressure on the discharge will be observed and the effect of impurities on the line spectrum of a discharge will be examined.

Sample Lab1 Marking Scheme as a PDF document. Marks are assigned to items identified in the lab outline as 'required' (refer to the lab outline for details)
Lab Sessions:
  Group A during the week of 2013/01/14
  Group B during the week of 2013/01/21
  All Sections DUE one week after the lab


Lab 2 - Pressure Measurement
A two week lab in which students alternate parts A and B in two consecutive weeks. Pressure measurement techniques for high-vacuum systems are examined. The performance of various roughing gauges will be investigated for accuracy over a given range and the effect of gas composition on gauge accuracy will be investigated. Residual gas analysis is then performed in which gas samples will be analyzed for isotopic purity using a quadrupole mass spectrometer - in addition to pure gases such as neon and carbon dioxide, air will be analyzed.

Sample Lab2 Marking Scheme as a PDF document. Marks are assigned to each question as shown.


Lab 3 - Gas laser tubes
Students will use a high-vacuum system (including turbomolecular pump and RGA) to evacuate and reprocess a helium-neon gas laser tube. Processing includes outgassing the tube by thermal and gas flushing methods. Students will be required to adjust pressure of the gas mix used (helium and neon) to optimize laser tube output. Once optimized, the tube will be sealed and monitored for long-term stability (i.e. the effects of residual gases in the tube such as trapped oxygen will be observed). Residual gas analysis will be used to show how gases evolve as the laser operates and E/P calculations will be performed comparing experimental to theoretical ratios for neon.

Sample Lab3 Marking Scheme as a PDF document. Marks are assigned to each question as shown.


Lab 4 - Basic Thin Film Techniques: Thermal Evaporation Deposition
Students will operate a high-vacuum thermal deposition system to deposit a thin-film of aluminum onto glass substrates. During this lab students will be exposed to the operating principles of high-vacuum systems, practice working in a class-1000 cleanroom environment, gain experience controlling deposition rate by regulating filament current, and utilize in-process quartz crystal thickness monitoring to assure a proper film thickness.


Lab 5 - Optical Calibration of a Thin-Film monitor
Students will calibrate the tooling factors on a thin-film monitor by using optical means in which basic dielectric filters consisting of a layer of dielectric Na₃AlF₆ sandwiched between two thin layers of aluminum are fabricated. This structure, which resembles a Fabry-Perot interferometer, acts as a high-performance optical filter with a narrow spectral width. Filters will be modelled with thin film software, deposited in the cleanroom using the Bendix thermal evaporator, and filters will be analyzed by a Perkin-Elmer Lambda-3B spectrophotometer (in V12 outside the lab time). By correcting the model in software, the tooling factors for various substrate locations in the chamber will be determined.
PRELAB must be submitted to the lab instructor at least one-hour prior to the lab

Sample Lab Marking Scheme as a PDF document. Print and append as the last page of the lab report.


Lab #6 will be either ...

Lab 6 - Dielectric Mirrors (eBeam Deposition)
Students will design (using FilmStar software) then fabricate a QWOT multilayer dielectric mirror on 'Sparky', a 13kW eBeam deposition system. The resulting coating will be analyzed spectrographically.
PRELAB must be submitted to the lab instructor at least one-hour prior to the lab


... or ...

Lab 6 - Advanced Antireflective Coatings (Sputtering Deposition)
Students will design (using FilmStar software) then fabricate a multilayer antireflective coating on the newly rebuilt Lesker PVD-75 sputtering deposition system. The resulting coating will be analyzed spectrographically.
PRELAB must be submitted to the lab instructor at least one-hour prior to the lab


The lab schedule is subject to change based on availability of laboratory equipment

Course Notes and Links

• The TurboPump System system diagram and instructions for using the turbomolecular pumping facility in V12
  
• The Ocean Optics Spectrometer a brief intro to the spectrometer used in gas discharge experiments in V12.
• NIST eBook of spectral data - Required for many labs in this course.
• Gauges - Supplementary Notes on roughing gauges from class
  
• Ion Gauges
  
• Yeagle Technology Inc includes information on sources and interpreting RGA data (fragmentation)
• Application Notes: Using Q and S applying throughput and speed to a real system (examples)
  
• Notes On Pressure Reduction and gas composition as required for the gas laser reprocessing lab
  
• Kurt J. Lesker Company company site containing tutorials on Vacuum Basics including RGAs (Technical Info -> Vacuum Basics). Specific pages of interest:
• Vacuum Technology Fundamentals basic physics of gases, behaviour of vacuum systems (e.g. outgassing), and an excellent tutorial on how RGAs work and how results are interpreted. Required reading.
• Helix Technologies / CTI Cryogenics Cryopump fundamentals.
• High Vacuum Systems High Vacuum Systems - Summary of Operation, Valves&Flanges, and Leak Detection (from class)

• Notes On Loading Source Filaments how to calculate the amount of evaporant required for a particular deposition BEFORE the chamber is pumped down!
  
• Center for Applied Microtechnology at the University of Washington which features a cleanroom like ours. Specific pages of interest:
• Process Tutorials including vacuum systems and cleanroom operations
• CVC Vacuum Evap System standard operating procedures. This machine is similar to our CVC (Bendix) evaporator.
• Society of Vacuum Coaters Specific pages of interest:
• History Of Vacuum Coating a (large) article by Donald Mattox outlining essentially all coating technologies from a historical perspective. Required reading.
• Thin Film Applet allowing the exploration of how an antireflective coating works.
• Melles Griot Optics Guide covering the basics of optical coatings (required reading)
• Optical Structures 1 - Antireflective Coatings
• Optical Structures 2 - MDM Filters
• Optical Structures 3 - V Coatings
• Optical Structures 4 - Dielectric Reflectors
• What Is Sputtering? from AJA International, including animations.
• MFC Fundamentals from Advanced Energy
• Ellipsometry Tutorial from J.A. Woolam (manufacturer of spectroscopic ellipsometers)
• Deposition class notes on deposition technologies
• Reactive Sputtering class notes on this technique and mass flow control

• Final Review Questions

Lab Equipment used in this course

• The TurboPump System system diagram and instructions for using the turbomolecular pumping facility in V12 used for evacuating and filling gas discharge tubes as well as mass spectroscopy experiments.
• The Ocean Optics Spectrometer a brief intro to the spectrometer used in gas discharge experiments in V12.
• The Bendix High-Vacuum Deposition System details of system components including pumps, gauges, and valves. See also the page from U.Washington above which features operating procedures.
• The Alcatel TurboPump System system diagram and instructions for using the second turbomolecular pumping facility in V12 used for research and projects.

Contacts:

For the Photonics Technician/Technology programs ...
Program Coordinator Alexander McGlashan
Telephone (905) 735-2211 x.7513
E-Mail:

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