\[\sigma\left(z\right)=\frac{2\omega_{1}}{\pi}\exp\left(\frac{\eta_{1}z^{2}}{2%
\omega_{1}}\right)\sin\left(\frac{\pi z}{2\omega_{1}}\right)\prod_{n=1}^{%
\infty}\frac{\sin\left(\pi(2n\omega_{3}+z)/(2\omega_{1})\right)\sin\left(\pi(2%
n\omega_{3}-z)/(2\omega_{1})\right)}{{\sin}^{2}\left(\pi n\omega_{3}/\omega_{1%
}\right)}.\]