Crystalline Mirror Solutions


Ultralow loss mid-IR optics
ppm-level optical losses

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    Center wavelength

    2 µm

    5 µm

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    Optical losses

    < 10 ppm (scatter + absorption)

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    200 nm FWHM

    400 nm FWHM



Optical transmission
Tunable, per customer request
Coating material
Single-crystal GaAs/AlGaAs
Substrate material
Typically single-crystal silicon, other materials possible
Substrate diameter
0.5 - 1 inch (12.7 - 25.4 mm), other sizes available
Radius of curvature (ROC)
>0.1 m
Surface flatness
<0.10 wave P-V measured @ 633 nm
Surface quality
<5 Å RMS micro-roughness
Similar to fused silica, cleaning instructions provided on request

Trace Gas Sensing

The potential for unprecedentedly low optical losses in the MIR spectral regime open the way to completely new capabilities of MIR laser systems and applications, including medical and environmental monitoring. The latter is of significant interest as many large molecules for atmospheric science, medicine, and national security have fundamental vibrational transitions in this region, making it ideal for trace detection efforts. Cavity enhanced detection methods provide the best sensitivity and low-loss optical systems based on crystalline mirror technology will be able to generate a significant impact for such MIR sensing applications. Even without dedicated development efforts, the first crystalline MIR cavity ringdown prototype mirrors already show an optical performance on par with the best coatings present on the commercial market.

Relevant publications

  • Direct frequency comb measurement on OD + CD -> DOCO kinetics

    B. J. Bjork, T. Q. Bui, O. H. Heckl, P. B Changala, B. Spaun, P. Heu, D. Follman, C. Deutsch, G. D. Cole, M. Aspelmeyer, M. Okumura, J. Ye

    Science, Vol. 354, Issue 6311, 444-448, 28 Oct 2016

  • High-performance near- and mid-infrared crystalline coatings

    G. D. Cole, W. Zhang, B. J. Bjork, D. Follman, P. Heu, C. Deutsch, L. Sonderhouse, J. Robinson, C. Franz, A. Alexandrovski, M. Notcutt, O. H. Heckl, J. Ye, M. Aspelmeyer

    “High-performance near- and mid-infrared crystalline coatings”, Optica, Vol. 3, No. 6, 647-656, June 2016.