以皮秒雷射脈衝及濕蝕刻技術製作光束整形擴散之微透鏡陣列

在光學領域中，雷射因有其獨特的高指向、同調、單色等特性，得以使其在光學領域研究中佔有一席之地。常見雷射光能量是以一高斯分佈(Gaussian distribution)形成，而若能將雷射之高指向性與高斯分佈特性作為一可控制且能使光均勻分散，即可應用於不同之雷射照明領域系統之開發。本研究擬透過製作微透鏡陣列(Microlens array, MLA)作為雷射的光學散射元件。因此利用Light Tools光學模擬追跡軟體進行單一微透鏡之光學模擬，並以軟體內建之貝茲曲線(Bezier curve)進行微透鏡參數設計，找尋其輪廓對於光強分佈趨勢，後續將其結構以不同排列與間距變化，進行模擬與分析光形與光強度分佈影響。接續以模擬中得到之結果，進行皮秒雷射微加工於矽酸鹽玻璃表面，通過不同雷射功率、脈衝發數、加工排列與濕蝕刻技術結合，最終可形成不同排列與深寬比之微透鏡陣列。在後續光學系統分析中發現與模擬相同，當不同的排列與微透鏡輪廓皆會影響光形的變化，而將本實驗成果進行光學量測可得到散射角度29°至62°之方形微透鏡陣列，並且產生六邊形、長矩形等不同光形之微透鏡陣列之光學散射元件。

關鍵字

皮秒雷射加工；濕蝕刻技術；雷射整束；微透鏡陣列

並列摘要

Laser has unique characteristics for its high directionality, coherence, and monochromaticity, which make it can be applied in many fields of optics. The fundamental mode of laser light is Gaussian spatial distribution. If the high directionality and Gaussian distribution characteristics of the laser light can be adjusted to different spatial uniformity and light shaping, which can be applied to the laser illumination systems. In this study, optical software Light Tools was used to simulate the optical behavior of laser light passes through the single micro-lens. We used Bezier curve theory to adjust the profile of microlens. The microlens profile, space between the microlenses and pattern distribution of the microlenses would influence the intensity distribution and light pattern. Following the results obtained in the simulation, we used picosecond laser to do the micromachine on the surface of the glass. The different arrangements and aspect ratios of microlenses were formed through different laser machining parameter such as laser power, laser pulses number, laser scanning pattern and wet etching process. From the optical measurement, different arrangements and microlens profiles would affect the laser light shaping. The results show that square, rectangular and hexagonal shape can be obtained successfully. The divergent angle square light pattern can be controlled 29° to 62°.

並列關鍵字

Picosecond Laser ； Wet Etching Process ； Beam Shaping ； Microlens Arrays

參考文獻

[1]維基百科, Ruby laser, https://en.wikipedia.org/wiki/Ruby_laser

Google Scholar

[2]H. P. Kuo, M. Y. Chuang, C. C. Lin, “Design correlations for the optical performance of the particle-diffusing bottom diffusers in the LCD backlight unit”, Power Technology, Vol. 192, 116-121, 2009