Crystalline Mirror Solutions


Thermally optimized optics

Active and passive semiconductor structures combined with high-conductivity substrates

  • cms_products_custom_assets_2

    Center wavelength

    900 nm

    5000 nm

  • cms_products_custom_assets_9

    Optical losses

    < 5ppm (scatter + absorption)

  • cms_products_custom_assets_12

    Coating thermal conductivity

    > 30 W / (m · K)



Optical transmission
Tunable, per customer request
Coating material
Single-crystal GaAs/AlGaAs
Substrate material
Diamond, SiC, or other materials possible
Coating area
200 mm diameter maximum, custom geometries possible
Surface flatness
<0.10 wave P-V measured @ 633 nm
Radius of curvature (ROC)
>0.1 m
Surface quality
<5 Å RMS micro-roughness, surface overcoat optional
S2 surface
AR coated for transmissive optics, super-polished, rough-cut, or metal coatings also available
Similar to fused silica, cleaning instructions provided on request

High-Power Lasers

xtal therm is our crystalline supermirror solution for high-power and ultrafast laser systems. With a thermal conductivity >30× higher than traditional sputtered coatings, these mirrors offer superior thermal management in harsh environments and are typically integrated with high-performance SiC or diamond substrates. Active functionality (e.g. saturable absorption) may also be realized in these structures.

Relevant publications

  • 16 W DBR-free membrane semiconductor disk laser with dual-SiC heatspreader

    Z. Yang, D. Follman, A. R. Albrecht, P. Heu, N. Giannini, G. D. Cole, and M. Sheik-Bahae.

    "16 W DBR-free membrane semiconductor disk laser with dual-SiC heatspreader," Electronics Letters, vol. 54, no. 7, pp. 430-432, 5 April 2018.

    A record output power of 16.1 W with a direct-bonded dual-SiC-heatspreader distributed Bragg reflector (DBR)-free active region at 10.5 °C coolant temperature is reported. A comparison in laser performance confirms the dual-heatspreader DBR-free configuration dissipates heat more effectively than the single-heatspreader geometry.

  • Optimized SESAMs for kilowatt-level ultrafast lasers

    A. Diebold, T. Zengerle, C. G. E. Alfieri, C. Schriber, F. Emaury, M. Mangold, M. Hoffmann, C. J. Saraceno, M. Golling, D. Follman, G. D. Cole, M. Aspelmeyer, T. Südmeyer, and U. Keller.

    "Optimized SESAMs for kilowatt-level ultrafast lasers,” Opt. Express 24, issue 10, 10512-10526, May 2016.

    We present a thorough investigation of surface deformation and thermal properties of high-damage threshold large-area semiconductor saturable absorber mirrors (SESAMs) designed for kilowatt average power laser oscillators. We compare temperature rise, thermal lensing, and surface deformation of standard SESAM samples and substrate-removed SESAMs contacted using different techniques. We demonstrate that for all cases the thermal effects scale linearly with the absorbed power, but the contacting technique critically affects the strength of the temperature rise and the thermal lens of the SESAMs (i.e. the slope of the linear change). Our best SESAMs are fabricated using a novel substrate-transfer direct bonding technique and show excellent surface flatness (with non-measureable radii of curvature (ROC), compared to astigmatic ROCs of up to 10 m for standard SESAMs), order-of-magnitude improved heat removal, and negligible deformation with absorbed power. This is achieved without altering the saturation behavior or the recovery parameters of the samples. These SESAMs will be a key enabling component for the next generation of kilowatt-level ultrafast oscillators.