Focal varying microlens array

Abstract

We report a novel microlens array with different curvature unit lenses (MLADC) fabricated with femtosecond laser direct writing technology. The MLADC consisted of hexagonal hyperboloid unit microlenses, which have different heights and curvatures from others. The unique optical performance of imaging and focusing capability were demonstrated. An object was imaged at different positions from the MLADC by unit lenses, as the ability of adjusting the curvature of the image plane for overall MLADC. In addition, the experiment had a good agreement with simulation results, which was based on the analysis of the finite element method. The novel MLADC will have important applications in improving the performance of optical systems, especially in field curvature correction and real-time three-dimensional imaging.

Apodization‐Assisted Subdiffraction Near‐Field Localization in 2D Phase Diffraction Grating

“…If the gap between the phase steps increases, the waveguide mode in the grating becomes more leaky and the resonances shifts toward shorter wavelengths . Thus, because the DGs considered here possess sufficiently large fill‐factor κ > 0.5, the Fano resonances observed in our simulations are not sharp (quality factor less than 10 2 ) in contrast to the previous works where the fill‐factor was lower, κ<< 1.…”

“…Of considerable interest are the DGs with high fill‐factor> 0.5, when the optical field is concentrated mainly near the grating stripes and the regions with high spatial localization of radiation (photonic jets) arise. In these conditions, the DG can be considered as an optical focusing element similar to a lenslet array with a short focal length …”

Progress in femtosecond laser fabrication of artificial compound eye

“…. 激光光 图 1 (网络版彩色)飞秒激光双光子三维(3D)加工系统示意图 [68,69] Figure 1 (Color online) Schematic of 3D femtosecond laser nanofabrication system via two-photon photopolymerization [68,69] 2 (Color online) Focal varying compound eye lens by femtosecond laser writing [39] . 图 3 (网络版彩色)双光子聚合像素调制制备仿生人工复眼 [40] .…”

Single-pulse writing of a concave microlens array

“…Microlens arrays (MLAs) have been proven to be important and irreplaceable optical devices due to their capability of integration, small volume, low cost, and distinctive optical performance in expanding the number of applications in microfabrication [1,2], 3D displays [3], beam shaping [4,5], and integrated optofluidic microchips [6]. Various methods have been proposed for fabrication of MLAs, such as laser direct writing (LDW) [7,8], thermal photoresist reflow [9], droplet inkjet [10], grayscale lithography [11], and multi-beam interference [12]. However, these methods are suitable only for soft materials, which limits the usage of MLAs in extreme environments.…”