## Abstract

Two photon transitions from the 5 $^{2}$P$_{\frac{1}{2}}^{0}$ and $^{2}$P$_{\frac{3}{2}}^{0}$ states of In have been observed to high lying $^{2}$P$^{0}$ and $^{2}$F$^{0}$ states. Extended series corresponding to P$^{0}$ $\rightarrow $ $n$P$^{0}$ and P$^{0}$ $\rightarrow $ $n$F$^{0}$ transitions are seen to $n=23$ and $n=31$ respectively. A hybrid resonance through intermediate states of In$_{2}$ gives rise to a series 6s $^{2}$S $\rightarrow $ $n$p $^{2}$P$^{0}$ which can be followed to $n=42$. Resonant enhancement of the 5 $^{2}$P$_{\frac{3}{2}}^{0}$ $\rightarrow $ $n$p $^{2}$P$^{0}$ series occurs because of an intermediate $^{2}\text{S}$ state. This produces a singularity in the cross section for this transition. Possible two photon transitions to autoionizing states of In are also seen.