  Two-mode coupling is very common and basic in optics. Recently, a lot more
works are focusing on the optical mode coupling with gain and loss due to its
tighter link to actual world. For a couple between one gain and one loss mode,
by adjusting the coupling constant, the mode in the spectrum will at first stay
then move after the constant passing some critical point. This phase transition
can be explained by non-Hermitian PT phase transition theory.However, only few
works research the spontaneous emission adjustment based on this procedure. It
has a lot of promising utilization in on chip optic systems if we can adjust
spontaneous emission. We look more deeply in this mode coupling process using
metallic nanorods, find the Exceptional Point, show the phase transition
between PT symmetry and PT broken regime, and show the adjustment to quantum
dot emission. Our work not only promote the understanding of multi-mode system,
but also bring up with a new way to adjust high enhancement of spontaneous
emission, tamping the foundation for future on chip nano photonics.
