laser dye performance a.jaqueline mena university of hawai’i- hilo w.m. keck observatory mentor:...
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Laser Dye Performance
A. Jaqueline Mena University of Hawai’i- Hilo
W.M. Keck ObservatoryMentor: Kenny Grace
Advisor: Jason Chin
Funding provided through the Center of Adaptive Optics, a National Science Foundation Science and Technology Center (STC), AST-987683
Photo Credit: John McDonald, CFHT
Overview• Background
Information:– Laser Guide Star– Dye Laser
• Introduction:– Problem– Purpose– Goal
• Experiment– Set-up/Procedure
• Analysis– Peak-to-Valley Ratios– Spectral Slopes– Dye Concentration
Measurements
• Results and Conclusion
• Acknowledgements
Laser Guide Star (LGS)
589nm Excites sodium layer
Creates an artificial guide star
Allows image correction:
Background Photo: http://www.kaunana.com/Default.aspx?tabid=62Courtesy of W.M.Keck and UCLA
Basic Dye Laser
Layout: Keck’s Laser
DMODye Master Oscillator
6 Yag LasersYttrium Aluminum Garnet
Problem The observatory presently has no method for determining when its laser dye should be changed
to maintain the laser guide star’s performance. Old dye can cause down time on the laser for
several nights.
Old dye……new dye, see our problem?
R2 Perchlorate Dye dissolved and diluted in Ethanol
Old DMO Dye
• Output power was 9 watts
After the dye was replaced…
• Output power was 18 watts
This means…
• The laser is twice as efficient with the new dye
To find consistent characteristics in old dyes’ spectra that will help determine when the dye should
no longer be used.
Purpose
Goal
To create a specific procedure for analyzing laser dye samples, and
to identify the spectral features that change most with dye age
and overexposure .
Steve Doyle holding up a small sample of old dye
Experiment
• Four Dye Samples: New Dye, Dye with 200 hours of use, Old Amplifier (Amp) dye (unknown exposure
time), and Old Dye Master Oscillator (DMO) Dye (unknown exposure time)
• New Dye
• 200 Hr. Dye
• Old Amp Dye
• Old DMO Dye
Peak-to-Valley Subtractions
Subtracted: B-A, B-C, D-E, F-G
A B
C
D
E
FG
-2
0
2
4
6
8
10
12
14
1 2 3 4 5 6 7
DMO Amp 200 Hr New
12
34
S1
0
0.001
0.002
0.003
0.004
0.005
0.006
0.007
0.008
0.009
0.01
Slopes between 253.08-240.03nm
• New Dye• 200 Hr. Dye• Old Amp Dye• Old DMO Dye
Old DMO
Old Amp 200 Hr. New
12
34
S1
-0.001-0.0005
00.0005
0.0010.0015
0.002
0.0025
0.003
0.0035
0.004
Slopes between 284.39-269.08nm
•New Dye•200 Hr. Dye•Old Amp Dye•Old DMO Dye
11%
127%89%
Concentration Measurements
• New Dye: 0.22678
• 200 Hr. Dye: 0.226780%
• Old Amp Dye: 0.1385839%
• Old DMO Dye: 0.1488734%
•Dye should be changed when the bar graph of the peak-to-valley subtraction calculations changes in pattern compared to the new dye.
-2
0
2
4
6
8
10
12
14
1 2 3 4 5 6 7
•Dye should be changed when the slope changes by more than 30% of the original.
•Dye should be changed when the concentration drops by 30%
•Dye should be changed when the graph’s peak at 546.69nm drops by 30%
Acknowledgments Center for Adaptive Optics
Sarah Anderson
Lisa Hunter
Scott Seagroves
Hilary O’Bryan
Internship short course staff
My internship peers
Everyone at W.M. Keck Observatory
Taft Armandroff
Kenny Grace
Ron Mouser
Kathy Muller
Steve Shimko
Jason Chin
University of Hawai’i at Hilo
Institute for Astronomy
Thank YOU for your time and support!
Funding provided through the Center of Adaptive Optics, a National Science Foundation Science and Technology Center (STC), AST-987683
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