Positive/negative phase shift bimetallic zone plate
The invention provides a positive/negative phase shift bimetallic zone plate and production method thereof, wherein the positive/negative phase shift bimetallic zone plate comprises: a first metallic material having a positive phase shift; a second metallic material having a negative phase shift at a working energy point; wherein the first metallic material and the second metallic material are alternately arranged, so that the second metallic material replaces the blank portion in a cycle of a traditional zone plate.
1. A positive/negative phase shift bimetallic zone plate; comprising:
a first metallic material having a positive phase shift;
a second metallic material having a negative phase shift at a working energy point;
wherein the first metallic material and the second metallic material are alternately arranged, so that the second metallic material replaces the blank portion in a cycle of a traditional zone plate.
2. The positive/negative phase shift bimetallic zone plate of claim 1 , wherein the positive/negative phase shift bimetallic zone plate is annular, and the first metallic material and the second metallic material form a structure of alternate rings.
3. The positive/negative phase shift bimetallic zone plate of claim 1 , the first metallic material is selected from nickel, gold, germanium, titanium, vanadium, chromium, manganese, iron, copper, zinc.
4. The positive/negative phase shift bimetallic zone plate of claim 1 , the second metallic material is selected from titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, gallium, germanium, hafnium, tungsten, rhenium and osmium.
5. The positive/negative phase shift bimetallic zone plate of claim 1 , wherein in the case that the positive/negative phase shift bimetallic zone plate has the same thickness as that of a normal monometallic phase zone plate, the diffraction efficiency of the positive/negative phase shift bimetallic zone plate is higher than the diffraction efficiency of the normal monometallic phase zone plate in conventional ranges.
6. The positive/negative phase shift bimetallic zone plate of claim 1 , the positive/negative phase shift bimetallic zone plate is a vanadium-nickel, titanium-nickel, or vanadium-gold bimetallic zone plate.
7. A method of producing a positive/negative phase shift bimetallic zone plate, comprising following steps:
a. depositing a thin film of a first metallic material on a substrate;
b. forming a photoresist having a zone plate structure on the thin film of the first metallic material;
c. transferring the zone plate structure to the thin film of the first metallic material by performing etching via the formed photoresist having the zone plate structure, so as to form a zone plate structure of the first metallic material;
d. depositing the second metallic material at interspaces formed by the etching;
e. removing the photoresist, so as to form a positive/negative phase shift bimetallic zone plate structure.
8. The method of claim 7 , wherein the photoresist is coated by spin coating, and thereafter is subjected to electron beam exposure
or interference lithography, so as to form a photoresist having a zone plate structure.
9. The method of claim 7 , wherein the etching in step d is performed by argon ion etching or reactive ion etching.
10. The method of claim 7 , further comprising:
opening a window on the back side of the positive/negative phase shift bimetallic zone plate structure obtained in step e, to obtain the positive/negative phase shift bimetallic zone plate.