  We propose and demonstrate a passively biased 2 by 2 thermo-optic switch with
high power efficiency and fast response time. The device benefits from the
highly concentrated optical field of a slot waveguide mode and the strong
thermo-optic effect of a nematic liquid crystal (NLC) cladding. The NLC fills
the nano-slot region and is aligned by the subwavelength grating inside. The
measured power consumption and thermal time constant are 0.58 mW and 11.8
microsecond, respectively, corresponding to a figure-of-merit of 6.8. The
proposed silicon-organic hybrid device provides a new solution to design
thermo-optic actuators having lower power consumption and fast operation speed.
