Application to the Gas Metrology of CO 2 H 2 O and N 2 O Adam J Fleisher David A Long Joseph T Hodges Material Measurement Laboratory National Institute of Standards amp Technology ID: 628540
Download Presentation The PPT/PDF document "Precision Cavity-enhanced Dual-comb Spec..." is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
Slide1
Precision Cavity-enhanced Dual-comb Spectroscopy:
Application to the Gas Metrology of CO2, H2O, and N2O
Adam J. Fleisher,
David A. Long, Joseph T. Hodges
Material Measurement Laboratory
National Institute of Standards & TechnologyGaithersburg, MD 20899, USASlide2
Quantitative CE-DCSElectro-optic frequency combs are an agile laser platform for rapid spectroscopy from 0.4 – 2.0 µm.
To perform quantitative cavity-enhanced dual-comb spectroscopy (CE-DCS), we require an accurate model of the complex multiheterodyne signal.
D.A. Long et al.,
Opt. Lett. 39, 2688 (2014).A. J. Fleisher et al.,
Opt. Express 24, 10424 (2016).Slide3
Electro-optic frequency combs
Utilize two EOFCs originating from the same CW laser to perform DCS
PD
EC
ECDL
FS
FS
EOM
LO
EOM
probe
AOM
LO
Sample
FC
FC
FL
FL
FA
Local Oscillator + Probe
or
Local Oscillator + Reference
D.A. Long et al.,
Opt. Lett.
39
, 2688 (2014).
A. J. Fleisher et al.,
Opt. Express
24
, 10424 (2016).Slide4
Cavity-enhanced DCS
A.J. Fleisher et al., in preparation.
Cavity locked to
HeNe (dither)CW laser locked to cavity (PDH)fAOM phase locked to RF reference (Cs clock)
EO comb spacing phase locked to RF reference (Cs clock)CW laser frequency measured against stabilized OFC (Cs clock)Slide5
Ideal case: frep = FSR
f
rep
=
FSR
1
2
3
−3
−2
−1
0
qSlide6
Mode mismatch I
1
Δ
2
Δ
3
Δ
−3
Δ
−2
Δ
−1
Δ
PDH
f
rep
− FSR= +
ΔSlide7
Mode mismatch II
molecular absorber
±1
Δ
±2
Δ
±3
Δ
±3
Δ
±2
Δ
±1
Δ
PDH
f
rep
− FSR= +
Δ
f
rep
− FSR= −
ΔSlide8
Model of CE-DCS
A.J. Fleisher et al, in preparation.
A.
Foltynowicz
et al.,
Appl. Phys. B
110
, 163 (2013).
L
= 74 cm
F
= 18,500
L
eff
= 4.4 km
FSR
= 203 MHz
δ
cav
= 10 kHz
R
+
T
+
= 1
q
= mode order (-M/2 … 0 … M/2)
Δ = mode spacing offset
δ
0
= PDH lock offset
Slide9
Carbon dioxide (12C16O
2)A.J. Fleisher et al., in preparation.
30012 Band of
12C16O2 at
cm
−1
R16e line at
cm
−1
Slide10
Carbon dioxide (12C16O
2)
Fit transition frequencies vs. m to obtain upper-state inertial parameters and origin frequency for 30012 band of 12C16O
2Uncertainty in Gv
of 1.9 MHz(
)
CE-DCS inertial parameters and origin frequency are in good agreement with FS-CRDS
A.J. Fleisher et al, in preparation.
D.A. Long et al.,
JQSRT
161
, 35 (2015).
30012 Band of
12
C
16
O
2
at
cm
−1
Slide11
Water (H216O)
A.J. Fleisher et al., in preparation.
040
000
10
1,10
9
0,9
and
040
000
6
2,5
6
1,6
Obs. − Calc. ≤ 0.01
rms
in 1 s
Pressures of 2.68, 4.50, and 6.20
Torr
Slide12
Water (H216O)
Deviations from HITRAN12 are as large as 20
MHz.
Absolute transition frequencies for H
2O measured by CE-CRDS agree with highly accurate FS-CRDS experiments.
A.J. Fleisher et al., in preparation.
040 Band of H
2
16
O from
= 6300 - 6335 cm
−1
Slide13
Nitrous Oxide (14N216
O)A.J. Fleisher et al., in preparation.
Analysis of the 4200 band of N2
O currently in progress65 transitions at low pressureP = 0.55 TorrSlide14
Performance and Outlook
Single-element noise-equivalent absorption coefficient
cm
−1
Hz
−1/2
Broadband applications – Octave-spanning EO combs
High-resolution applications – Self-heterodyne read-out to reduce
K. Beha et al,
Optica
4,
406 (2017).
D.A. Long et al.,
Phys. Rev. A
94
, 061801(R) (2016).Slide15
Acknowledgements
MMLDavid Long
Zachary ReedJoseph Hodges
PMLDavid Plusquellic
NIST Greenhouse Gas Measurements and Climate Research ProgramNRC Postdocs opportunities: adam.fleisher@nist.govSlide16
Blank
A.J. Fleisher et al., Opt. Express 24, 10424 (2016)Slide17
Model
A.J. Fleisher et al., in preparation
.Slide18
Model evaluation I
Δ = −2 kHz
δPDH = 2 kHz
P = 13 Pa (0.1
Torr) CO2
ν0 = 6364.750 cm
−1
λ
0
= 1571 nm
G.-W. Truong et al.,
J. Chem. Phys.
138
, 094201 (2013)Slide19
Model evaluation II
Δ = −2 kHz
δPDH = 0
P
= 13 Pa (0.1 Torr) CO
2ν0
= 6364.750 cm
−1
λ
0
= 1571 nmSlide20
Model evaluation III
Δ = +2 kHz
δPDH = 0
P
= 13 Pa (0.1 Torr) CO
2ν0
= 6364.750 cm
−1
λ
0
= 1571 nmSlide21
Carbon dioxide (12C16O
2)A.J. Fleisher et al, in preparation.
D.A. Long et al., JQSRT 161, 35 (2015).
30012 Band of 12C16O
2 at
cm
−1
G
v
B
v
D
v
(10−3)
H
v
(10−9)
11698.469997536
-3.998627717
0.411169933
30012 (CRDS)
190303782.258(59)
11585.62864(39)
-2.94262(69)
15.81(32)
30012 (CE-DCS)
190303781.5(1.9)
11585.62636(69)
-2.9373(21)
14(22)
G
v
B
v
D
v
(10−3)
H
v (10−9)
11698.469997536
-3.9986277170.411169933
30012 (CRDS)190303782.258(59)11585.62864(39)-2.94262(69)15.81(32)
30012 (CE-DCS)190303781.5(1.9)11585.62636(69)
-2.9373(21)14(22)
Spectroscopic constants in MHzSlide22
EOM comb outline
Explore MULTIHETERODYNE (Dual-Comb) using commercially-available low V
π fiber-coupled waveguide electro-optic modulators (EOMs) and tunable CW lasers in the near-IR
Retro-fit to existing CW lasers throughout the laboratory (fiber, DFB, ECDL, etc.)
Interrogate samples using existing optical cavities throughout the laboratory (i.e., no need to construct a cavity of specific FSR)
−
+
6dB
<10 kHz – 18 GHz
Dual-Drive MZM
<4
V
rms
T. Sakamoto et al.,
Opt. Lett
.
32
, 1515 (2007)
Slide23
RF Detuning
Amplitude
Amplitude
Amplitude
Optical Detuning
Optical Detuning
Optical Detuning
Amplitude
Local Oscillator (LO)
f
n,LO
=
nf
mod
+
f
0
Probe
f
n,Probe
=
n(
f
mod
+
δ
f
mod
)
+
f
0
+
f
AOM,
Probe
Heterodyne RF Signal
f
n,RF
=
n
δ
f
mod
+
f
AOM
,Ref
+
n
δ
f
mod
+
f
AOM,
Probe
Reference (Ref)
f
n,Ref
=
n(
f
mod
+
δ
f
mod
)
+
f
0
+
f
AOM
,RefSlide24
Relative phase stabilization
Detector
Phase Frequency Detector
Loop Filter
BPF
VCO
AOM
Laser
Amp
RF Reference
10 MHz Clock
Probe or Ref.
RF Cable
Optical Fiber
Local Oscillator
A.J. Fleisher et al.,
Opt. Express
24
, 10424 (2016)Slide25
Reduction in RF linewidth
t = 10 sRBW = 10 Hzinset:
t = 10 sRBW = 200 mHz
A.J. Fleisher et al.,
Opt. Express 24, 10424 (2016)Slide26
Coherent averaging
A.J. Fleisher et al., Opt. Express 24, 10424 (2016)
Without the AOM phase lock, successively triggered interferograms can not be coherently averaged
With the AOM phase lock, the signal-to-noise on a single comb tooth amplitude improves by
Coherent averaging for more than 2 hours!
6 TB/h
Slide27
Coherent averaging
t
acq = 200 μs
Δfmod = 300 kHzN = 1000noise reduction by
Slide28
Fast acquisition
t
acq = 10 μs
Δfmod = 300 kHzN = 1000noise reduction by
Slide29
Nitrous Oxide (14N216
O)A.J. Fleisher et al, in preparation.R.A. Toth, “
Linelist of N2O Parameters from 500 to 7500 cm−1,” database.
4200 Band of 14N2
16O at
cm
−1
G
v
B
v
D
v
(10−3)
H
v
(10−9)
12561.6338
5.279910
-0.49552
4200e (Toth)
18873277.1
12363.7210
6.472684
122.51
4200e (CE-DCS)
190303781.5(1.9)
11585.62636(69)
-2.9373(21)
14(22)
G
v
B
v
D
v
(10−3)
H
v (10−9)
12561.6338
5.279910-0.49552
4200e (Toth)18873277.112363.72106.472684122.51
4200e (CE-DCS)190303781.5(1.9)11585.62636(69)
-2.9373(21)14(22)
Spectroscopic constants in MHz