Thermal Analysis of Optics
Temperature variations impact the performance of optical systems due to thermoelastic effects that cause positional and dimensional changes in optical elements and thermooptic effects that change the index of refraction of optical materials. Temperature changes can also cause structural failures in lens elements, flexures, and bonds. The use of passive and active thermal control techniques are employed to maintain temperatures within their operational and nonoperational levels to meet performance and structural integrity requirements. Thermal models are used to perform design trades and predict the resulting temperature distribution over the optical system which can be used for both thermoelastic and thermooptic analyses. The flow of data for a typical design is shown in Figure 13.1. Several challenges involving the interaction and data flow are also addressed in this chapter. For complex systems with demanding performance and environmental requirements, integrated thermal–structural–optical models are beneficial to quantitatively assess thermal management strategies relative to optical performance. Analogies for adhesive curing and hygroscopicity are also discussed.