The temperature stability of optical reference cavities is significant in state-of-the-art ultra-stable narrow-linewidth laser systems. In this paper, the thermal time constant and thermal sensitivity of reference cavities are analyzed when reference cavities respond to environmental perturbations via heat transfer of thermal conduction and thermal radiation separately. The analysis as well as simulation results indicate that a reference cavity enclosed in multiple layers of thermal shields

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... larger mass, higher thermal capacity and lower emissivity is found to have a larger thermal time constant and thus a smaller sensitivity to environmental temperature perturbations. The design of thermal shields for reference cavities may vary according to experimentally achievable temperature stability and the coefficient of thermal expansion of reference cavities. A temperature fluctuation-induced length instability of reference cavities as low as 6 × 10 −16 on a day timescale can be achieved if a two-layer thermal shield is inserted between a cavity with the coefficient of thermal expansion of 1 × 10 −10 /K and an outer vacuum chamber with temperature fluctuation amplitude of 1 mK and period of 24 hours. , "A narrow linewidth and frequency-stable probe laser source for the 88 Sr + single ion optical frequency standard," Appl. Phys. B 95(1), 43-54 (2009). 22. J. Alnis, A. Matveev, N. Kolachevsky, Th. Udem, and T. W. Hansch, "Subhertz linewidth diode lasers by stabilization to vibrationally and thermally compensated ultralow-expansion glass Fabry-Perot cavities," Phys. Rev. A 77, 053809 (2008). "Contribution of thermal noise to frequency stability of rigid optical cavity via hertz-linewidth lasers," Phys. Rev. A 73, 031804(R) (2006).