CN-117222089-B - Method for generating selectable frequency EUV light source by using slab waveguide with periodic square groove structure

Abstract

A method for generating a selectable frequency EUV light source by using a slab waveguide with a periodic square groove structure belongs to the field of laser physics, and Extreme Ultraviolet (EUV) and soft X-ray light radiation are generated by using the interaction of femtosecond laser and a gaseous medium. The invention comprises a slab waveguide with a periodic square groove structure, a bracket or a device required for adjusting the slab waveguide with the periodic square groove structure, a platform or a guide rail system for precisely controlling the position movement, a base or a supporting structure for stabilizing and fixing equipment or components, and a gas supply system for filling gas into the slab waveguide with the periodic square groove structure and using inert gas to push experiments. The periodic square groove structure is used as a gas carrier, so that the conversion efficiency of extreme ultraviolet and soft X-ray light radiation can be effectively improved, and the harmonic order with the highest conversion efficiency can be changed by adjusting the period of the square groove structure, thereby adjusting and controlling the wavelength distribution of higher harmonic emission and realizing the frequency-selective output of the extreme ultraviolet light source.

Inventors

• SONG HAIYING
• ZHANG WEI
• AN WENYUAN
• LIU SHIBING

Assignees

• 北京工业大学

Dates

Publication Date

20260512

Application Date

20230816

Claims (3)

1. 1. A method for generating a selectable frequency EUV light source by using a slab waveguide with a periodic square groove structure is characterized by adopting the slab waveguide with the periodic square groove structure as an air-borne device of an air-filled gas, wherein the device comprises a glass block (1-1) stacked below and a glass block (1-10) stacked above, a first thin glass sheet (1-4), a second thin glass sheet (1-5), a third thin glass sheet (1-6) and a fourth thin glass sheet (1-7), the thicknesses of the first thin glass sheet, the second thin glass sheet, the third thin glass sheet and the fourth thin glass sheet are 0.2-1mm, and the method comprises the following specific manufacturing steps: Step 1, manufacturing a glass block with a periodical square groove structure and a groove structure serving as a gas inlet, wherein a first periodical square groove structure (1-2) is manufactured on the upper surface of a glass block (1-1) stacked below, a second periodical square groove structure (1-3) is manufactured on the lower surface of a glass block (1-10) stacked above, a first groove structure (1-8) forming the gas inlet is manufactured on the edge of the glass block (1-1) stacked below, a second groove structure (1-9) forming the gas inlet is manufactured on the edge of the glass block (1-10) stacked above, a third groove structure (1-13) forming the gas inlet is manufactured on the edge of the glass block (1-10) stacked above, and a fourth groove structure (1-14) forming the gas inlet is manufactured on the edge of the glass block (1-10) stacked above; Step 2, manufacturing thin glass sheets, namely, according to the sizes of the glass sheets (1-1) stacked below and the glass sheets (1-10) stacked above and the structures manufactured on the surfaces of the glass sheets, which are processed in the step 1, processing the first thin glass sheet (1-4), the second thin glass sheet (1-5), the third thin glass sheet (1-6) and the fourth thin glass sheet (1-7), aligning the processed thin glass sheets along the edges of the four right angles and two sides of the glass sheets (1-1) stacked below respectively, forming a cross shape in the area, which is not occupied by the thin glass sheets, of the upper surface of the glass sheets (1-1) stacked below, and adjusting the space between the second thin glass sheet (1-5) and the fourth thin glass sheet (1-7), and the space between the first thin glass sheet (1-4), and the third thin glass sheet (1-6), and adjusting the space between the fourth thin glass sheet (1-7), and the space between the second thin glass sheet (1-5) and the third thin glass sheet (1-6), and adjusting the space between the gas inlets; And 3, assembling the slab waveguide with the periodic square groove structure, and aligning and placing the upper surface of the glass block (1-1) stacked below and the lower surface of the glass block (1-10) stacked above from bottom to top according to the manufactured periodic square groove structure I (1-2), periodic square groove structure II (1-3) and groove structure I (1-8) used for forming a gas inlet, groove structure II (1-9) forming a gas inlet, groove structure III (1-13) forming a gas inlet and groove structure IV (1-14) forming a gas inlet, so as to sandwich the thin glass sheet I (1-4), the thin glass sheet II (1-5), the thin glass sheet III (1-6) and the thin glass sheet IV (1-7) from bottom to top, and assembling by using vacuum glue.
2. 2. A method according to claim 1 for producing a selectable frequency EUV light source using a periodic square groove structured slab waveguide, characterized in that in order to modulate the EUV spectrum produced by the periodic square groove structure in the slab, a waveguide adjusting device is used, which is composed of a stage or rail system (3-1) for precisely controlling the position movement, a base or support structure (3-2) for stabilizing and fixing the apparatus or component, a slab waveguide device (3-3) with the periodic square groove structure, a gas supply system (3-4) for filling the slab waveguide with the periodic square groove structure with a gas and using an inert gas propulsion experiment, a bracket or device (3-5) required for adjusting the slab waveguide with the periodic square groove structure is used, and the specific installation adjusting steps are as follows: Step 1, a flat waveguide device (3-3) with a periodic square groove structure is arranged on a bracket or a device (3-5) required by adjusting the flat waveguide with the periodic square groove structure, and the longitudinal angle of the flat waveguide device is adjusted by adjusting the bracket or the device required by the flat waveguide with the periodic square groove structure; Step 2, installing a bracket or a device (3-5) required by adjusting the slab waveguide with the periodic square groove structure on a platform or a guide rail system (3-1) for precisely controlling the position movement, and adjusting the up-down positions of the bracket or the device required by the slab waveguide with the periodic square groove structure and the upper waveguide device by adjusting the platform or the guide rail system for precisely controlling the position movement; Step 3, mounting a platform or a guide rail system (3-1) for precisely controlling the position movement on a base or a supporting structure (3-2) for stabilizing and fixing equipment or components, adjusting the transverse angle of the whole device by rotating the base or the supporting structure for stabilizing and fixing the equipment or components, and adjusting the front-back and left-right positions of the whole device by translating the base or the supporting structure for stabilizing and fixing the equipment or components; Step 4, filling gas into the slab waveguide with the periodic square groove structure, and connecting and sealing the gas supply system (3-4) for the inert gas propulsion experiment with the slab waveguide device (3-3) with the periodic square groove structure; Step 5. Adjusting the up and down position of the slab waveguide device (3-3) with the periodic square groove structure by adjusting the stage or guide rail system (3-1) for precisely controlling the position movement so that the slab waveguide port is at the same height as the femtosecond laser, adjusting the front and back, left and right positions of the base or support structure (3-2) for stabilizing and fixing the apparatus or component so that the laser is aligned to the slab waveguide port and the focus is located inside the waveguide, rotating the base or support structure (3-2) for stabilizing and fixing the apparatus or component and adjusting the bracket or device (3-5) required for adjusting the slab waveguide with the periodic square groove structure so that the transverse and longitudinal angles of the slab waveguide with the periodic square groove structure can pass through the slab waveguide, and then fixing the base or support structure for stabilizing and fixing the apparatus or component in the vacuum target chamber.
3. 3. A method of producing a selectable frequency EUV light source using a slab waveguide of a periodic square groove structure as claimed in claim 1, wherein: The mixed beam of the femtosecond laser and the higher harmonic wave is emitted out of a flat waveguide outlet with the periodic square groove structure and enters a spectrometer vacuum chamber, only extreme ultraviolet radiation is left after the femtosecond laser is filtered by a filter, and finally, the extreme ultraviolet radiation is collected by a spectrometer after being split by a grating element.

Description

Method for generating selectable frequency EUV light source by using slab waveguide with periodic square groove structure Technical Field The invention relates to a novel scheme for generating Extreme Ultraviolet (EUV) soft X-ray light radiation by utilizing the interaction of femtosecond laser and a gaseous medium and regulating and controlling the emission and wavelength distribution of the extreme ultraviolet soft X-ray light radiation, belonging to the field of laser physics. Background With the continuous progress of laser technology, further obtaining a stable light source with shorter wavelength and stronger radiation is a goal that scientists continuously pursue. At present, EUV radiation has become an important point of research due to its important application value in the fields of physics, biochemistry, materials, chip manufacturing and the like. The main modes of generating EUV (10-120 nm) light radiation are by synchrotron radiation light sources, discharge plasma (DPP), laser plasma (LPP), and higher (secondary and higher) harmonic radiation (HHG), etc. The EUV light source generated by DPP and LPP is mainly applied to the field of extreme ultraviolet lithography, the emission wavelength of the EUV light source depends on the property of a target, and the higher harmonic wave generated by ultra-short pulse drive has the unique properties of narrow radiation band, adjustable wavelength and the like, is an extremely effective way for generating ultra-short pulse width, high space and time coherent EUV and soft X-rays, has a wider spectrum range (covering infrared to ultraviolet), and has a wavelength as short as a 'water window' wave band (2.3-4.4 nm), and the EUV light source obtained by HHG radiation has the characteristics of high cost performance, easy acquisition, good coherence and the like, so that the EUV light source has greatly developed in the aspect of desk-top equipment processing. However, the problems of low conversion efficiency of coherent EUV and soft X-ray sources obtained from higher harmonic radiation severely limit their further applications and conventional methods are difficult to produce tunable EUV radiation. Therefore, the focus is on obtaining a tunable high power EUV light source that can be applied in practical engineering. The problem of serious phase mismatch exists in the generation of HHG in free space, so that a quasi-phase matching mechanism is generated, and the core thought is that the higher harmonic phase is compensated in a plurality of in-phase areas, so that higher harmonic signals can be coherently enhanced, therefore, researchers propose a plurality of quasi-phase matching methods, namely a periodic arrangement and alternate arrangement gas box scheme, a reverse transmission light pulse scheme, a polychromatic field scheme, a microelectrode modulation scheme, an inner diameter periodic variation hollow capillary scheme and the like, but because the obtaining of extreme ultraviolet light usually requires the whole device to be in a high vacuum state, the periodic arrangement and alternate arrangement gas box scheme can cause the severe variation of the vacuum degree of a vacuum chamber to influence the emission of the extreme ultraviolet radiation, and the reverse transmission light pulse, the polychromatic field and the microelectrode modulation scheme can introduce additional instruments and equipment to make the whole device more complex, and the hollow capillary scheme with the periodic variation of the inner diameter has the problem of manufacturing difficulty. Disclosure of Invention Aiming at the problems faced by the regulation and control of EUV and extreme ultraviolet radiation, the invention provides a novel method for improving the conversion efficiency of higher harmonic waves and realizing the frequency-selective output of EUV radiation. In order to achieve the above object, the present invention proposes an experimental solution for modulating EUV radiation using a slab waveguide with a periodic square groove structure. The scheme mainly comprises a flat waveguide with a periodical square groove structure, a bracket or a device required by adjusting the flat waveguide with the periodical square groove structure, a platform or a guide rail system for precisely controlling position movement, a base or a supporting structure for stabilizing and fixing equipment or components, and a gas supply system for filling gas into the flat waveguide with the periodical square groove structure and using inert gas to push an experiment. A method for generating a selectable frequency EUV light source by using a slab waveguide with a periodic square groove structure is characterized by adopting the slab waveguide with the periodic square groove structure as an air-borne device of inflation gas, wherein the device comprises a glass block (1-1) stacked below and a glass block (1-10) stacked above, a first thin glass sheet (1-4), a second thin glass sheet (