An infrared imaging lens that produces beams with long focal depth while preserving the entire aperture for full light capturing and high transverse resolution is presented. Based on the conjugate-gradient algorithm, a diffractive optical lens with four times depth of focus improvement at the 10.6-µm wavelength has been designed and fabricated. ZEMAX simulation has confirmed the designed lens performance showing legible images over an extended image range. Through laser direct-write photoresist patterning and subsequent reactive ion etching on a germanium substrate, we have realized a diffractive lens with four times depth of focus improvement over a conventional infrared lens of the same numerical aperture. The extended depth of focus lens should yield a variety of applications in focus-free imaging without reducing lens aperture.
Partially conjugated PPV derivatives as an emitting material were prepared in order to control the emitting color. According to the control of the conjugation length of the PPV emitters by using the conjugation interrupt atoms such as nitrogen (N-PPV) or silicon (Si-PPV) in their polymer backbone, various emitting PPV derivatives have been obtained. Highly efficient bright white emitter can be realized through simple mixing of various PPV derivatives.
An infrared imaging lens that produces beams with long focal depth whilst preserving the entire aperture for full light capturing and high transverse resolution is presented. It is a diffractive optical element that generates a long range of pseudo-non-diffractive rays. The design technique is based on the conjugate-gradient algorithm. The surface relief pattern was generated on a thick film photoresist and then the pattern was transferred to germanium substrate. Preliminary experimental results demonstrated four times improvement in depth of focus at 10.6 μm wavelength.
We report on the non-lithographic laser writing fabrication of polymer waveguide fanout on a newly developed 4'-
hydroxy-4-nitroazobenzene dye functionalized polymer film. It can avoid the time consuming costly error correction re-fabrication in conventional optical waveguide fabrication by lithographic techniques when encountering error due to imperfect fabrication. The laser writing correction of power splitting ratio on waveguide directional coupler and y-branch fanouts has been demonstrated.