Opt Lett. 2018 Jul 1;43(13):3029-3032. doi: 10.1364/OL.43.003029.
We propose and experimentally demonstrate a novel experimental scheme to generate high on-axis peak intensity, segmented, smooth, zero-order quasi-Bessel beams with tunable ranges. Illuminating the axicon with hollow Gaussian beams (HGBs) of different orders, we have generated Bessel beams of varying ranges at different positions away from the axicon. The presence of a dark core at the center of the HGBs removes the effect of imperfection in the axicon tip. As a result, the entire power of the input beam is transformed into a zero-order Bessel beam without any on-axis intensity modulation. We observe the decrease in range and increase in on-axis peak intensity of the zero-order Bessel beam with the order of HGBs. Controlling the superposition of the HGBs of different orders to the axicon, we have demonstrated the increase in the range of the Bessel beam. The current technique can also produce Bessel beams of different intensity distributions, including single-peak or multiple-peak Bessel beams. Using single-pass second-harmonic generation in nonlinear crystals of different lengths, we have further verified the increase of on-axis peak intensity of the Bessel beam with the order of the HGBs and the increase in the range of the Bessel beam due to the superposed HGBs.
我们提出并实验验证了一种新颖的实验方案，用于产生具有可调范围的高轴上峰值强度、分段、平滑、零阶准贝塞尔光束。用不同阶数的空心高斯光束（HGB）照射轴棱锥，我们在远离轴棱锥的不同位置生成了具有不同范围的贝塞尔光束。HGB 中心的暗核消除了轴棱锥尖端不完美的影响。因此，输入光束的全部功率都转换为零阶贝塞尔光束，而没有任何轴上强度调制。我们观察到零阶贝塞尔光束的范围减小和轴上峰值强度增加与 HGB 的阶数成正比。通过控制不同阶数的 HGB 对轴棱锥的叠加，我们演示了贝塞尔光束范围的增加。当前的技术还可以产生具有不同强度分布的贝塞尔光束，包括单峰或多峰贝塞尔光束。使用不同长度的非线性晶体中的单次通过二次谐波产生，我们进一步验证了随着 HGB 阶数的增加，贝塞尔光束的轴上峰值强度增加，以及由于叠加的 HGB 导致贝塞尔光束范围的增加。
