Precision Interferometry with Semiconductor Crystalline Mirrors

Based on previous efforts to minimise mechanical dissipation in highly reflecting micromechanical resonators our group has introduced epitaxial AlGaAs Bragg reflectors as an alternative to conventional dielectric mirror material. The single-crystal heterostructure gives rise to a significant increase in mechanical Q (when compared to dielectrics), while maintaining excellent reflectivity. This is of direct relevance for ultra-high-performance interferometry applications such as gravitational wave interferometers and cavity-based optical frequency standards, where the residual phase noise, also referred to as coating thermal noise, is known to limit the overall system sensitivity. Jointly with the group of Jun Ye et JILA we were able to confirm the dramatically improved thermal noise-performance of this materials system. These findings form the basis for a new technology based on the unique features of single-crystal semiconductor coatings for high-end laser applications. Examples include ultra-low thermal noise for laser precision measurements (e.g. ultra-stable lasers, gravitational wave detectors, etc.), high thermal conductivity for ultrafast- and high-power-lasers, and ultra-low optical losses in the mid-IR regime (2-10 micron) e.g. for cavity based trace-gas sensing.

Publications (selected):

Coherent cancellation of photothermal noise in GaAs/Al0.92Ga0.08As Bragg mirrors
T. Chalermsongsak, E. D Hall, G. D. Cole, D. Follman, F. Seifert, K. Arai, E. K Gustafson, J. R. Smith, M. Aspelmeyer and R. X. Adhikari
Metrologia, Volume 53, Number 2 (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
Optica Vol. 3, Issue 6, pp. 647-656 (2016)

Direct Frequency Comb Measurement of OD + CO -> 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, pp. 444-448 (2016)

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
Optics Express Vol. 24, Issue 10, pp. 10512-10526 (2016)

Sensing earth's rotation with a helium-neon ring laser operating at 1.15  μmK.
U. Schreiber, R. J. Thirkettle, R. B. Hurst, D. Follman, G. D. Cole, M. Aspelmeyer, and J.-P. R. Wells
Optics Letters 40, 1705-1708 (2015)

Reduction of residual amplitude modulation to 1×10-6 for frequency-modulation and cavity-based laser stabilization
W. Zhang, M. J. Martin, C. Benko, J. L. Hall, J. Ye, C. Hagemann, T. Legero, U. Sterr, F. Riehle, G. D. Cole, M. Aspelmeyer
Optics Letters, vol. 39, no. 7, pp. 1980-1983 (2014)

Tenfold reduction of Brownian noise in high-reflectivity optical coatings
G. D. Cole, W. Zhang, M. J. Martin, J. Ye, M. Aspelmeyer
Nature Photonics 7, 644-650 (2013)