Cavity locking with spatial modulation of optical phase front for laser stabilization

We study optical cavity locking for laser stabilization through spatial modulation of the phase front of a light beam. A theoretical description of the underlying principle is developed for this method and special attention is paid to residual amplitude modulation (RAM) caused by experimental imperfections, especially the manufacture errors of the spatial phase modulator. The studied locking method owns the common advantages of the Pound-Drever-Hall method and the tilt-locking one, and it can provide a more artful way to eliminate RAM noise in phase modulation for the ultimate stability of lasers. In situations where cost and portability are a practical issue, the studied method allows one to realize compact laser stabilization systems locked to Fabry-P$\acute{\mbox{e}}$rot cavities without use of expensive bulky devices, such as signal generators and electro-optic modulators.