\documentclass{scrartcl}
\usepackage{color}
\usepackage{multicol}
\usepackage[final]{graphicx}
\usepackage{pst-plot,pstricks}
	\input{pstplot-logarithmic-axes}
\begin{document}
	\psset{xunit=25cm,yunit=20cm}
	\begin{pspicture}(-0.11,-0.1)(0.11,0.15)
		\psaxes[Dx=10,Dy=0.1]{->}(0,0)(-0.11,-0.01)(0.11,0.15)
		\psplot[plotstyle=curve]{-0.1}{0}{x -1 mul x x mul 1 add sqrt div}
		\psplot[plotstyle=curve]{0}{0.1}{x x x mul 1 add sqrt div}
		\psline[linestyle=dotted](-0.1,0)(-0.1,0.1)
		\psline[linestyle=dotted](0.1,0)(0.1,0.1)
		\rput(-0.1,-0.01){$-\omega_g$}
		\rput(0.1,-0.01){$\omega_g$}
		\rput(0.11,0.01){$\omega$}
		\rput[r](-0.01,0.13){$\left|\underline{H}_a\left(j\omega\right)\right|$}
	\end{pspicture}
\end{document}
