Phase modulation device, phase modulation device fabrication method, crystallization apparatus, and crystallization method

Abstract

A phase shifter which modulates the phase of incident light has a light-transmitting substrate such as a glass substrate, and a phase modulator such as a concavity and convexity pattern which is formed on the laser beam incident surface of the light-transmitting substrate and modules the phase of incident light. A light-shielding portion which shields light in the peripheral portion where the optical intensity distribution decreases of the phase modulator is formed on the laser beam incident surface or exit surface of the phase shifter, thereby shielding the peripheral light in the irradiation surface of the incident laser beam.

1 . A phase modulation device including a light-transmitting substrate, and a concavity and convexity pattern which is formed on the light- transmitting substrate and modulates a phase of incident light, comprising:
 a light-shielding member which is formed on at least one of an incident surface and an exit surface of the light-transmitting substrate, and shields the incident light which enters a predetermined peripheral portion of the concavity and convexity pattern and a peripheral portion of the light-transmitting substrate.   
     
     
         2 . A device according to  claim 1 , wherein the light-shielding member is at least one of a reflector, an absorber, a scatterer and a thin film. 
     
     
         3 . A device according to  claim 1  or  2 , wherein the light-shielding member is at least one of aluminum, an aluminum alloy, and chromium. 
     
     
         4 . A device according to  claim 3 , wherein the aluminum alloy is an Al—Si alloy. 
     
     
         5 . A device according to  claim 1 , wherein a film thickness of the light-shielding member is 30 to 2,000 nm. 
     
     
         6 . A device according to  claim 1 , wherein when the light-shielding member is aluminum, a film thickness of the light-shielding member is 50 to 2,000 nm. 
     
     
         7 . A device according to  claim 1 , wherein when the light-shielding member is an Al—Si film, a film thickness of the light-shielding member is 80 to 2,000 nm. 
     
     
         8 . A method of fabricating a phase modulation device including a light-transmitting substrate, and a modulator which is formed on the light-transmitting substrate and modulates a phase of incident light, comprising:
 forming, on the light-transmitting substrate, light-shielding means for shielding peripheral light in an irradiation surface of the incident light to the light-transmitting substrate.   
     
     
         9 . A method of fabricating a phase modulation device including a light-transmitting substrate, and a concavity and convexity pattern which is formed on the light-transmitting substrate and modulates a phase of incident light, comprising:
 forming, on one of an incident surface and an exit surface of the light-transmitting substrate, a light-shielding member which shields the incident light to a predetermined peripheral portion of the concavity and convexity pattern and an outer peripheral portion of the light-transmitting substrate.   
     
     
         10 . A method according to  claim 9 , further comprising forming a through hole portion in a central portion of the light-shielding member by wet etching.