Pyroelectric biosensors generate an electric current as a result of a temperature change.  This differential induces a polarization in the substance, producing a dipole moment in the direction of the temperature gradient.  The result is a net voltage across the material.  This net voltage can be calculated by the following equation.
where V = Voltage,
ω = angular frequency of the modulated incident,
P = pyroelectric coefficient,
L = film thickness,
ε = film dielectric constant,
A = area of film,
r = resistance of the film,
C = capacitance of the film,
τE = electrical time constant of the detector output.