Apurv Chaitanya N, Chaitanya Kumar S, Devi Kavita, Samanta G K, Ebrahim-Zadeh M
Opt Lett. 2016 Jun 15;41(12):2715-8. doi: 10.1364/OL.41.002715.
We report on the generation of ultrafast vortex beams in the deep ultraviolet (DUV) wavelength range at 266 nm, for the first time to our knowledge. Using a Yb-fiber-based green source in combination with two spiral phase plates of orders 1 and 2, we were able to generate picosecond Laguerre-Gaussian (LG) beams at 532 nm. Subsequently, these LG beams were frequency doubled by single-pass, second-harmonic generation in a 10 mm-long β-BaBO crystal to generate ultrafast vortex beams at 266 nm with a vortex order as high as 12, providing up to 383 mW of DUV power at a single-pass, green-to-DUV conversion efficiency of 5.2%. The generated picosecond UV vortex beam has a spectral width of 1.02 nm with a passive power stability better than 1.2% rms over >1.5 h.
据我们所知，我们首次报道了在266nm深紫外（DUV）波长范围内产生超快涡旋光束。通过将基于镱光纤的绿色光源与两个1阶和2阶螺旋相位板相结合，我们能够产生532nm的皮秒拉盖尔 - 高斯（LG）光束。随后，这些LG光束在一块10mm长的β - BaBO晶体中通过单程二次谐波产生进行倍频，以产生高达12阶涡旋的266nm超快涡旋光束，单程提供高达383mW的深紫外功率，绿光到深紫外的转换效率为5.2%。所产生的皮秒紫外涡旋光束的光谱宽度为1.02nm，在超过1.5小时的时间内，无源功率稳定性优于均方根值1.2%。
