Structure of optical singularities in coaxial superpositions of Laguerre-Gaussian modes.
We investigate optical singularities in coaxial superpositions of two Laguerre-Gaussian (LG) modes with a common beam waist from the viewpoints of a general formulation of phase structure, experimental generation of various superposition beams, and evaluation of the generated beams' fidelity. By applying a holographic phase-amplitude modulation scheme using a phase-modulation-type spatial light modulator, output fidelity beyond 0.960 was observed under several typical conditions. Additionally, an elliptic-type folded singularity, which provides a different class of phase structures from familiar helical singularities, was predicted and observed in a superposition involving two LG modes of both radially and azimuthally higher orders.
Hamamatsu Photonics K.K., Central Research Laboratory, 5000 Hirakuchi, Hamamatsu-City 434-8601, Japan. taro@crl.hpk.co.jp
Taro
T
Ando
Naoya
N
Matsumoto
Yoshiyuki
Y
Ohtake
Yu
Y
Takiguchi
Takashi
T
Inoue