Extreme Ultraviolet Polarization Vortex Beam Based on High Harmonic Generation

Polarization is a property of vector beam that is widely used in many areas of science and technology. And vector beam is also called polarization vortex beam. Radially polarized beam and azimuthally polarized beam are the paradigm of vector beam. Extreme ultraviolet (EUV) vector beam could be applied in many fields such as diffractive imaging, Extreme Ultraviolet Lithography (EUVL), or ultrafast control of magnetic properties. In our experiments, a home-made EUV spectrometer was used to generate a tunable ultrafast EUV coherent light source based on high-order harmonic generation (HHG) by intense femtosecond laser. The apparatus features by using the plane grating in conical diffraction. The radially polarized vector beam and Gaussian beam with 800 nm, 35 fs laser pulses were applied to interact with Argon atoms, respectively. The high harmonic spectrums with a polarization singularity and a Gaussian distribution were observed. The experimental results demonstrate that the EUV vector beam could be transfered from


实验装置
本研究用于产生和探测强激光场诱导的高次谐波光谱仪和单色仪在我们之 前的研究 [29][30][31]  为了实现对产生的极紫外短波涡旋结构观测，通过使用 Czerny-Turner 方案 设计的单色仪将 HHG 光谱进行单色分光成像探测，如图 1 下半部光路所示。单 色仪具体实现方案 [32]  外波段 [20]     Polarization is a property of vector beam that is widely used in many areas of science and technology.And vector beam is also called polarization vortex beam.Radially polarized beam and azimuthally polarized beam are the paradigm of vector beam.Extreme ultraviolet (EUV) vector beam could be applied in many fields such as diffractive imaging, Extreme Ultraviolet Lithography (EUVL), or ultrafast control of magnetic properties.In our experiments, a home-made EUV spectrometer was used to generate a tunable ultrafast EUV coherent light source based on high-order harmonic generation (HHG) by intense femtosecond laser.
The apparatus features by using the plane grating in conical diffraction.
The radially polarized vector beam and Gaussian beam with 800 nm, 35 fs laser pulses were applied to interact with Argon atoms, respectively.
The high harmonic spectrums with a polarization singularity and a Gaussian distribution were observed.The experimental results demonstrate that the EUV vector beam could be transfered from

最 新 录 用
near-infrared driven laser during the highly nonlinear interaction.The short-wavelength radiation with a polarization singularity can reach a photon flux of 10 8 per second.And the harmonic orders produced by Gaussian beam are significantly higher than that of vector field.The mechanism of macroscopic phase matching was discussed.It indicates that the phase matching for vector harmonic yields is similar with that driven by a Gaussian beam.In this case, EUV vector beam through HHG has been obtained, which provides one important method for attosecond vector pulses and opens new possibilities for exploring and manipulating the time-dependent evolution of quantum states in atom and molecule.
Keywords: high-order harmonic generation, extreme ultraviolet polarization vortex field, phase matching, polarization singularities

Fig. 2 .
Fig. 2. Part of the HHG spectrum of Ar atoms at 90 torr irradiated by a 800 nm, 35 fs linearly polarized and radially polarized driving laser field with laser energy of 1.0 mJ: (a) Part of the HHG spectrum produced by a Gaussian driving beam; (b) The corresponding integrated HHG intensity; (c) Part of the HHG spectrum produced by a radially polarized driving beam; (d) The corresponding integrated HHG intensity.The x-order of the harmonics are labeled as Hx in the figure.

3. 2
Fig. 3. Far-field intensity distributions of EUV light with the orders of 21st generated with Gaussian beam and radially polarized beam: (a) EUV generated by Gaussian beam; (b) EUV vortex generated by radially polarized beam.

19 图 5 .Fig. 5 .
Fig. 5. Yield of the modes as a function of the gas pressure and laser energy for the harmonic and vortex harmonic: (a) Harmonic with the orders of 19th; (b) Harmonic with the orders of 23rd.基于单色仪实验测量过程中，由于优选单色波长采用的是光栅的非经典安装 Moses J, Huang S W, Granados E, Keathley P, Bhardwaj S,