Astigmatic Multipass Absorption Cells

Light-weight Astigmatic Multipass Absorption Cell – AMAC-36LW

A new lightweight (1.25 kg) 36 meter (0.3 liter volume) Astigmatic Multipass Absorption Cell, the AMAC-36LW uses the same high-efficiency multipass optical design as our AMAC-36, but with less than half the mass. A similar lightweight cell is also available with 76 meter path length, 0.5 liter volume, the AMAC-76LW.


  AMAC-36 AMAC-76
Path length 36 (18) m 76 (55)
Base path 0.20 m 0.32 m
Number of passes 182 (90) 238 (174)
Volume 0.3 liters 0.5 liters
Mirror diameter 3.8 cm 3.8 cm
Optical axis height 6.4 cm 6.4 cm
In-out half-angle 5.1 degrees 3.2 degrees
Input hole diameter 4.3 mm 4.3 mm
Dimensions exterior
30 cm
7.6 cm
4.1 kg
42 cm
7.6 cm
4.4 kg
Optical Design Astigmatic two-mirror system with central coupling hole.
Mirrors Nickel plated aluminum with broad-band dielectric coating.
Wavelength range 3 to 11 µm (actual range may be broader).
Reflectivity 99.2 %
Window material BaF2
Body materials Nickel plated aluminum, stainless steel end flanges, Pyrex tube.



Dual quantum cascade laser trace gas instrument with astigmatic Herriott cell at high pass number, J. B. McManus, M S. Zahniser, D. D. Nelson, Appl. Opt., 50, A74-A85, 2011.

Application of quantum cascade lasers to high-precision atmospheric trace gas measurements, J. B. McManus, M. S. Zahniser, D. D. Nelson, Jr., J. H. Shorter, S. Herndon, E. Wood, R. Wehr, Opt. Eng. 49, 111124, 2010.

Paraxial Matrix Description of Astigmatic and Cylindrical Mirror Resonators with Twisted Axes for Laser Spectroscopy, B. McManus,  App. Optics, 46, 472-482, (2007).

Astigmatic mirror multipass absorption cells for long-path-length spectroscopy, J.B. McManus, P.L. Kebabian, and M.S. Zahniser, Applied Optics, 34, 3336-3348 (1995).

Measurement of Trace Gas Fluxes Using Tunable Diode Laser Spectroscopy, M.S. Zahniser, D.D. Nelson, J.B. McManus and P.L. Kebabian. Phil. Trans. Roy. Soc. Lond. A., 351, 371-382 (1995).


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