Optical systems making use of phase type fresnel zone plates

A Fresnel zone plate comprising:

• a Fresnel patterned surface having a plurality of areas, said plurality of areas including:
• a first area where 0-th order light of a single wavelength of diffracted light generated by an object passes, and
• a second area where said 0-th order light of said single wavelength of said diffracted light generated by said object does not pass;
• said Fresnel patterned surface being blazed such that a diffraction efficiency of said phase type Fresnel zone plate reaches a maximum with respect to a first given order of said single wavelength of said diffracted light generated by said object in said first area;
• and
• said Fresnel patterned surface being blazed such that said diffraction efficiency of said Fresnel zone plate reaches a maximum with respect to a second given order of said single wavelength of said diffracted light generated by said object in said second area, said second given order being different from said first given order.

A Fresnel zone plate comprising:

• a Fresnel patterned surface having a plurality of zones, said plurality of zones including:
• a first zone provided at a position where 0-th order light of light diffracted by an object passes, and
• a plurality of second zones provided at positions where said 0-th order light diffracted by said object does not pass;
• said Fresnel patterned surface being blazed such that a pitch of gratings formed thereon decreases from an optical axis toward a first zonal boundary, is increased past said first zonal boundary from said optical axis, and decreases again from past said first zonal boundary towards a second zonal boundary from said optical axis.

A projection optical system comprising:

• an illumination device emitting a single band of wavelength of light;
• an object illuminated by said single band of wavelengths of light and generating diffracted light therefrom;
• and
• a projection lens system including a Fresnel zone plate, said Fresnel zone plate comprising:
• a Fresnel patterned surface having a plurality of areas, said plurality of areas including:
• a first area where 0-th order light of said diffracted light passes, and
• a second area where said 0-th order light of said diffracted light does not pass;
• said Fresnel patterned surface being blazed such that a diffraction efficiency of said Fresnel zone plate reaches a maximum with respect to a first given order of light diffracted in said first area;
• and
• said Fresnel patterned surface being blazed such that said diffraction efficiency of said Fresnel zone plate reaches a maximum with respect to a second given order of light diffracted in said second area, said second given order being different from said first given order.

A projection optical system comprising:

• an illumination device emitting a single band of wavelength of light;
• an object illuminated by said single band of wavelengths of light and generating diffracted light therefrom;
• and
• a projection lens system including a Fresnel zone plate, said Fresnel zone plate comprising:
• a Fresnel patterned surface having a plurality of zones, said plurality of zones including:
• a first zone provided at a position where 0-th order light of said diffracted light passes, and
• a plurality of second zones provided at positions where said 0-th order light of said diffracted light does not pass;
• said Fresnel patterned surface being blazed such that a pitch of gratings formed thereon decreases from an optical axis toward a first zonal boundary, is increased past said first zonal boundary from said optical axis, and decreases again from past said first zonal boundary towards a second zonal boundary from said optical axis.