  In the present work I analyze the factors that affect signal generation in
the measurement of photothermal expansion with an atomic force microscopy
probe. I discuss the general properties of the signal transduction mechanism
considering two forms of light excitation, progressive and impulsive, and I
derive guidelines for performance optimization of the measurement. I also
provide a general framework to analyze the thermomechanical processes that
underlie signal generation in terms of a thermodynamic engine cycle and I
discuss the relationship between signal generation and efficiency of the
mechanism. The work has been subdivided into sections for the sake of clarity.
