Abstract: Example radar systems, optical detectors, vehicles, and optical detection methods are provided. An example radar system includes a laser device and an optical detector. The optical detector can include a first polarization scanner and a photosensitive device. The laser device can be configured to emit detection laser. The first polarization scanner can be configured to refract an echo signal of the detection laser, where a refractive index of the first polarization scanner is variable. The photosensitive device can be configured to sense the echo signal refracted by the first polarization scanner.

Abstract: A method of fabricating a field-effect transistor in which a native oxide layer is removed prior to etching a gate recess. The cleaning step ensures that the etch of the gate recess starts at the same time across an entire sample, such that a uniform gate recess depth and profile can be achieved across an array of field-effect transistors. This results in a highly uniform switch-off voltage for the field-effect transistors in the array.

Abstract: A method of fabricating a field-effect transistor in which a native oxide layer is removed prior to etching a gate recess. The cleaning step ensures that the etch of the gate recess starts at the same time across an entire sample, such that a uniform gate recess depth and profile can be achieved across an array of field-effect transistors. This results in a highly uniform switch-off voltage for the field-effect transistors in the array.