A method for improving lateral resolution and reducing imaging distortion of optical subtraction microscopy is pro-posed. First, an azimuthally polarized (AP) light is modulated by an annular aperture. Then, an image with higher lat-eral resolution is obt
We have proposed and experimentally demonstrated a novel scheme for efficient mid-infrared difference-frequency generation based on passively synchronized fiber lasers. The adoption of coincident seeding pulses in the nonlinear conversion process could su
A novel MEMS variable optical attenuator (VOA), which has completely different attenuation mechanism from those in literatures, is proposed and demonstrated in this paper. The basic operation principle is that the optical power coupled between two initial