We describe the design of a soldered sapphire optical viewport, which is useful for spectroscopic applications of samples at high temperatures and high pressures. The sapphire window is bonded via active soldering to a metal flange with a structure of two c-shaped rings made of different metallic materials in between, so as to mitigate thermally induced stress. A spectroscopic cell equipped with two of the optical viewports has been successfully operated with alkali metals in a noble gas environment at temperatures in the range of 20–450 °C at noble gas pressures from 10−6 mbar to 330 bars. In the upper pressure range, we observe a leakage rate smaller than our readout accuracy of 30 mbar per day.
REFERENCES
1.
S.
Svanberg
, “Laser-spectroscopic applications
,” in Atomic and Molecular Spectroscopy
(Springer
, 2004
), pp. 389
–460
.2.
S.
Khalafinejad
, C.
Von Essen
, H. J.
Hoeijmakers
, G.
Zhou
, T.
Klocová
, J. H. M. M.
Schmitt
, S.
Dreizler
, M.
Lopez-Morales
, T.-O.
Husser
, T. O. B.
Schmidt
et al., “Exoplanetary atmospheric sodium revealed by orbital motion-narrow-band transmission spectroscopy of HD 189733b with UVES
,” Astron. Astrophys.
598
, A131
(2017
).3.
G. G.
Hammes
, Spectroscopy for the Biological Sciences
(John Wiley & Sons
, 2005
).4.
M.
Leenen
, G.
Welp
, R.
Gebbers
, and S.
Pätzold
, “Rapid determination of lime requirement by mid-infrared spectroscopy: A promising approach for precision agriculture
,” J. Plant Nutr. Soil Sci.
182
, 953
–963
(2019
).5.
M. J.
Pelletier
et al., Analytical applications of Raman spectroscopy
(Blackwell Science Oxford
, 1999
), Vol. 427.6.
M.
Takeo
et al., “Broadening and shift of spectral lines due to the presence of foreign gases
,” Rev. Mod. Phys.
29
, 20
(1957
). 7.
S.
Christopoulos
, P.
Moroshkin
, L.
Weller
, B.
Gerwers
, R.
Forge
, T.
Ockenfels
, F.
Vewinger
, and M.
Weitz
, “Rubidium spectroscopy at high-pressure buffer gas conditions: Detailed balance in the optical interaction of an absorber coupled to a reservoir
,” Phys. Scr.
93
, 124006
(2018
).8.
T.
Vogler
and P.
Vöhringer
, “Probing the band gap of liquid ammonia with femtosecond multiphoton ionization spectroscopy
,” Phys. Chem. Chem. Phys.
20
, 25657
–25665
(2018
).9.
R. M.
Spearrin
, C. S.
Goldenstein
, J. B.
Jeffries
, and R. K.
Hanson
, “Quantum cascade laser absorption sensor for carbon monoxide in high-pressure gases using wavelength modulation spectroscopy
,” Appl. Opt.
53
, 1938
–1946
(2014
).10.
S. B.
Hansen
, R. W.
Berg
, and E. H.
Stenby
, “High-pressure measuring cell for Raman spectroscopic studies of natural gas
,” Appl. Spectrosc.
55
, 55
–60
(2001
).11.
D.
Sarkisyan
, D.
Bloch
, A.
Papoyan
, and M.
Ducloy
, “Sub-Doppler spectroscopy by sub-micron thin Cs vapour layer
,” Opt. Commun.
200
, 201
–208
(2001
).12.
J. M.
Alberigs
and J. M. L.
Penninger
, “An improved window seal for high temperature-pressure spectroscopic flow cells
,” Rev. Sci. Instrum.
45
, 460
–461
(1974
).13.
M. T.
Duignan
, D. J.
Gerhardt
, and W. T.
Whitney
, “Metal C ring window seal
,” Rev. Sci. Instrum.
60
, 3537
–3539
(1989
).14.
S.-Y.
Chang
, Y.-H.
Huang
, and L.-C.
Tsao
, “Active solders and active soldering
,” in Fillers-Synthesis, Characterization and Industrial Application
(IntechOpen
, 2019
).15.
16.
W. M.
Yim
and R. J.
Paff
, “Thermal expansion of AlN, sapphire, and silicon
,” J. Appl. Phys.
45
, 1456
–1457
(1974
).17.
Technical Datasheet CarTech®Kovar® Alloy, CRS Holdings, Inc., 1990, cRS Holdings, Inc. is a subsidiary of Carpenter Technology Corporation.
18.
S.
Mishra
, A.
Sharma
, D. H.
Jung
, and J. P.
Jung
, “Recent advances in active metal brazing of ceramics and process
,” Met. Mater. Int.
26
, 1087
–1098
(2020
).© 2021 Author(s). Published under an exclusive license by AIP Publishing.
2021
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