Microbolometer transfer function and impulse response

From Optical Imaging and Spectroscopy (Wiley - OSA 2009)
By David J. Brady
www.opticalimaging.org
Figure 5.16

pa=Plot[1/Sqrt[1 +  4 Pi^2 x^2 ],{x,0,4},Axes->False, Frame->True,FrameLabel->{ντ,(OverBar[h])},PlotStyle->{Black},PlotLabel->"(a)",PlotRange->All]

h[tau_]:=(E^(-tau)) HeavisideTheta[tau];

pb=Plot[h[t],{t,-.1,5},Axes->False, Frame->True,PlotStyle->{Black},PlotRange->All,PlotPoints->200,FrameLabel->{t/τ,h},PlotStyle->{Black},PlotLabel->"(b)"]

Show[GraphicsArray[{pa,pb}]]