12 th International User Meeting on Cavity Enhanced Spectroscopy 13 June 2017 1A12 Charles R Markus Jefferson E McCollum Thomas S Dieter Philip A Kocheril and Benjamin J McCall ID: 636109
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Slide1
CAVITY-ENHANCED SPECTROSCOPY OF MOLECULAR IONS IN THE MID-INFRARED WITH UP-CONVERSION DETECTION AND BREWSTER-PLATE SPOILERS
12
th
International User Meeting on Cavity Enhanced Spectroscopy, 13 June, 20171A12
Charles R. Markus
, Jefferson E. McCollum, Thomas S. Dieter, Philip A.
Kocheril
, and Benjamin J. McCallSlide2
NICE-OHVMS technique
DescriptionLimitations Removing parasitic etalonsMechanism of detectionBrewster-Spoiler plate
Up-conversion detectionDesignResultsFuture directionsOverviewSlide3
Astrochemistry
H
HHOver 190 molecules identified in the interstellar medium (ISM)Reactions must overcome cold and diffuse environment
Ion-neutral reactions dominate chemistry of ISMAleman, et al., A&A,2014, 566, A79.www.nasa.gov/mission_pages/hubblem
m
Slide4
Benchmark Molecular Systems
H
2+H2HeH+H3+
~10-5 cm-1 (~300 kHz)~2 x 10-4 cm-1 (~6 MHz)~0.01 cm-1 (~300 MHz)0.001 – 0.1 cm-1
(~30 MHz - 3
G
Hz)
V.
Korobov
,
Phys. Rev. A.
,
77
022509, (
2008)
G.D. Dickenson,
et al., Phys. Rev. Lett.
,
110
,
193601
, (2013)
K.
Pachucki
, and J.
Komasa
,
J. Chem. Phys.
,
137
,
204314, (
2012)
M.
Pavanello
,
et al.
,
J. Chem. Phys.
,
136
, 184303, (2012
)
&Slide5
Ion Spectroscopy
Ions are orders of magnitude less abundant than neutral speciesSlide6
NICE-OHVMS
Noise Immune Cavity Enhanced Optical Heterodyne Velocity Modulation Spectroscopy
B. M. Siller, et al., Opt. Express,2011, 19, 24822-7.Slide7
NICE-OHVMS
Noise Immune Cavity Enhanced Optical Heterodyne Velocity Modulation Spectroscopy
Increased Signal and PrecisionB. M. Siller, et al., Opt. Express,2011,
19, 24822-7.Slide8
NICE-OHVMS
Noise Immune Cavity Enhanced Optical Heterodyne Velocity Modulation Spectroscopy
Increased Signal and Precision
Improved SensitivityB. M. Siller, et al., Opt. Express,2011, 19, 24822-7.Slide9
NICE-OHMS
fheterodyne = nFSR
J.Ye
,
et al
.,
J. Opt. Soc. Am. B,
1998,
15, 6.
-1 MHz 0 MHz 1 MHzSlide10
NICE-OHVMS
Noise Immune Cavity Enhanced Optical Heterodyne Velocity Modulation
SpectroscopyIncreased Signal and Precision
Improved SensitivityIon-Neutral DiscriminationB. M. Siller, et al., Opt.
Express,
2011,
19
,
24822-7
.Slide11
Velocity Modulation
Velocity
C. S.
Gudeman
,
et al
.,
J. Chem. Phys.,
1983,
78, 5873.Slide12
Lock-in
Amplifier
Velocity Modulation
-
+
-
+
Velocity
C. S.
Gudeman
,
et al
.,
J. Chem. Phys.,
1983,
78, 5873.Slide13
Lock-in
Amplifier
Velocity Modulation
-
+
-
+
Velocity
B. M.
Siller
,
et al
.,
Opt. Lett.,
2010,
35, 1266.Slide14
Lock-in
Amplifier
Velocity Modulation
-
+
-
+
Lock-in
Amplifier
Referenced at
B. M.
Siller
,
et al
.,
Opt. Lett.,
2010,
35, 1266Slide15
NICE-OHVMS Spectrometer
YDFL
EOM
FSR
n
idler
=
n
pump
-
n
signal
4
0
kHz
OPO
PZT
ν
W
avemeter
Crabtree
,
et al
., Chem. Phys. Lett.,
2012,
551, 1-6.
A
OM
To optical frequency comb
PZTSlide16
Frequency Comb Calibration
AOM
OPO
Beat Detection & Offset LockingSlide17
NICE-OHVMS Spectrometer
YDFL
EOM
Lock-In Amplifier
X & Y Channels
Lock-In Amplifier
X & Y Channels
FSR
90
o
Phase Shift
2xf
=
80
kHz
n
idler
=
n
pump
-
n
signal
4
0
kHz
OPO
Lock Box
PZT
Slow
Fast
~9
MHz
W
avemeter
A
OM
To optical frequency comb
PZT
Crabtree
,
et al
., Chem. Phys. Lett.,
2012,
551, 1-6.Slide18
2
40 kHz
Lock-in 1
Lock-in 2
0
o
90
o
0
o
90
o
NICE-OHVMS Results
FSR
90
o
Mixer 1
Mixer 2
H
3
+
81720377.29(86) MHz
Slide19
Saturation Spectroscopy
Velocity (m/s)
(MHz)
Slide20
Saturation Spectroscopy
Velocity (m/s)
(MHz)
Slide21
Saturation Spectroscopy
Velocity (m/s)
(MHz)
Slide22
Saturation Spectroscopy
Velocity (m/s)
(MHz)
Slide23
Saturation Spectroscopy
Velocity (m/s)
(MHz)
Slide24
(MHz)
Saturation Spectroscopy
Velocity (m/s)Slide25
2
40 kHz
Lock-in 1
Lock-in 2
0
o
90
o
0
o
90
o
NICE-OHVMS Results
FSR
90
o
Mixer 1
Mixer 2
H
3
+
81720377.29(86) MHz
Slide26
Parasitic Etalons
H
3+ Slide27
Parasitic Etalons
FSR =
Slide28
Parasitic Etalons
FSR =
Webster
., J. Opt. Soc. B.,
1985,
2
, 1464-1470.Slide29
Spoiling Parasitic Etalons
Galvo
S/N (best channel)Off125On2000H3+ 2725.898 cm-1
GalvoS/N (best channel)Off125Markus, et al., Opt. Express.,2017, 25, 3709-3721.Slide30
Parasitic Etalons
H
3+
H3+ 80051601.4(23) MHz Slide31
Detector
Coverage (
μm) NEP (W Hz-1/2)3 dB BW (MHz)PVM-10.62.5 – 114.8160
DetectorCoverage (μm) NEP (W Hz-1/2)3 dB BW (MHz)PVM-10.62.5 – 11160DetectorCoverage (μm) NEP (W Hz-1/2)
NEP
eff
(W Hz
-1/2
)
3 dB BW (MHz)
PVM-10.6
2.5 – 11
4.8
4.8
160
PVI-4TE-6
2.8 – 6.5
1.7
6.8
700
Detector
Coverage (
μ
m)
NEP (W Hz
-1/2
)
NEP
eff
(W Hz
-1/2
)
3 dB BW (MHz)
PVM-10.6
2.5 – 11
160
PVI-4TE-6
2.8 – 6.5
700
Detector
Coverage (
μ
m)
NEP (W Hz
-1/2
)
NEP
eff
(W Hz
-1/2
)
3 dB BW (MHz)
PVM-10.6
2.5 – 11
4.8
4.8
160
PVI-4TE-6
2.8 – 6.5
1.7
6.8
700
DET025A
0.35 – 1.1
9.3
2.2
2000
Detector
Coverage (
μ
m)
NEP (W Hz
-1/2
)
NEP
eff
(W Hz
-1/2
)
3 dB BW (MHz)
PVM-10.6
2.5 – 11
160
PVI-4TE-6
2.8 – 6.5
700
DET025A
0.35 – 1.1
2000
Detection schemes
PVI
PVM
DPSS
= 6.7
/W
DET
532 nm, 6.4 W
PPLNSlide32
Up-conversion Results
Allan-Werle
plot5.9cm-1 Hz-1/2 Crabtree, et al
., Chem. Phys. Lett.,2012, 551, 1-6.Slide33
Mid-IR detector
Up-conversion detection
SNR: 17,000SNR: 3,000Up-conversion ResultsH3+ 2725.898 cm-1 Slide34
Heterodyne Detection
= 20% FWHM
Overlapping sub-Doppler features= 100% FWHMOptimized signal
Slide35
Up-conversion Results
H
3+ 2725.898 cm-1 Crabtree, et al., Chem. Phys. Lett.,2012,
551, 1-6.Slide36
Conclusion and Future Directions
Removed parasitic etalons with Brewster-plate spoiler
Improved sensitivity with up-conversion detectionH3+ 2670.2342 cm-1
Apply up-conversion to survey of H3+ Measure fundamental band (3 – 4.5 m)
Hotband
transitions
Implement SFG to cover overtone transitions (1.9 – 2.1
m)
Discipline idler completely to frequency comb
Slide37
Acknowledgments
Advisor: Ben McCall
Special thanks to:
Phil KocherilThomas DieterJeff McCollumAdam PerryJames Hodges