Laser scanning optical system and laser scanning optical apparatus

Claim 1

A method for obtaining a high resolution three-dimensional microscopic image of a sample having a three-dimensional thickness, comprising the steps of: emitting a parallel rays pulsed laser beam, said laser beam having a pulse duration of several ten to several hundred fs and a repetitive frequency of several ten to several hundred MH z ; shaping said laser beam into a cylindrical and annular cross-sectional ray bundle, by providing first and second convex axicon prisms which are disposed such that apexes thereof are opposed one to the other and said apexes are separated by a distance one from the other and optical axes thereof are coincident with each other and which are made of respective materials having substantially the same refractive index and shaped with a same apical angle; causing said laser beam to enter said first prism and then, after passing through said first prism, to enter said second prism; and adjusting a diameter of said ray bundle by adjusting said beam diameter either before said beam enters said first axicon prism or after said beam exits said second axicon prism; converging said shaped laser beam to produce a Bessel beam; changing a shape of three-dimensional intensity distribution of said Bessel beam by setting a ratio β of an outer diameter α of said ray bundle to an inner diameter α 1 (namely β=α/α 1 ) by adjusting said distance; irradiating said sample with said Bessel beam; detecting fluorescence light emitted by said sample responsive to irradiation by said Bessel beam; generating output signals corresponding to said detected light; and producing said microscopic image based on said output signals wherein said detecting step comprises the steps of: a) first detecting said fluorescence emitted from a surface side of said sample, and b) second detecting said fluorescence emitted from a back side of said sample; and wherein producing said microscopic image based on addition of output signals corresponding to said detected fluorescence.

Claim 2

A method for obtaining a high resolution three-dimensional microscopic image of a sample having a three-dimensional thickness, comprising the steps of: emitting a parallel rays pulsed laser beam, said laser beam having a pulse duration of several ten to several hundred fs and a repetitive frequency of several ten to several hundred MH z ; shaping said laser beam into a cylindrical and annular cross-sectional ray bundle, by providing first and second convex axicon prisms which are disposed such that apexes thereof are opposed one to the other and said apexes are separated by a distance one from the other and optical axes thereof are coincident with each other and which are made of respective materials having substantially the same refractive index and shaped with a same apical angle; causing said laser beam to enter said first prism and then, after passing through said first prism, to enter said second prism; and adjusting a diameter of said ray bundle by adjusting said beam diameter either before said beam enters said first axicon prism or after said beam exits said second axicon prism; converging said shaped laser beam to produce a Bessel beam; changing a shape of three-dimensional intensity distribution of said Bessel beam by setting a ratio β of an outer diameter α of said ray bundle to an inner diameter α 1 (namely β=α/α 1 ) by adjusting said distance; irradiating said sample with said Bessel beam; detecting fluorescence light emitted by said sample responsive to irradiation by said Bessel beam; generating output signals corresponding to said detected light; and producing said microscopic image based on said output signals wherein said detecting step comprises the steps of: a) first detecting said fluorescence emitted from a surface side of said sample, and b) second detecting said fluorescence emitted from a back side of said sample; and wherein producing said microscopic image based on addition of output signals corresponding to said detected fluorescence.

Claim 4

A method for obtaining a high resolution three-dimensional microscopic image of a sample having a three-dimensional thickness, comprising the steps of: emitting a parallel rays pulsed laser beam, said laser beam having a pulse duration of several ten to several hundred fs and a repetitive frequency of several ten to several hundred MH z ; shaping said laser beam into a cylindrical and annular cross-sectional ray bundle, by providing first and second convex axicon prisms which are disposed such that apexes thereof are opposed one to the other and said apexes are separated by a distance one from the other and optical axes thereof are coincident with each other and which are made of respective materials having substantially the same refractive index and shaped with a same apical angle; causing said laser beam to enter said first prism and then, after passing through said first prism, to enter said second prism; and adjusting a diameter of said ray bundle by adjusting said beam diameter either before said beam enters said first axicon prism or after said beam exits said second axicon prism; converging said shaped laser beam to produce a Bessel beam; changing a shape of three-dimensional intensity distribution of said Bessel beam by setting a ratio β of an outer diameter α of said ray bundle to an inner diameter α 1 (namely β=α/α 1 ) by adjusting said distance; labeling said sample with a predetermined fluorescent dye; irradiating said sample with said Bessel beam; detecting fluorescence light emitted by said sample responsive to irradiation by said Bessel beam; generating output signals corresponding to said detected light; and producing said microscopic image based on said output signals wherein said detecting step comprises: a) first detecting said fluorescence emitted from a surface side of said sample, and b) second detecting said fluorescence emitted from a back side of said sample; and wherein producing said microscopic image based on addition of output signals corresponding to said detected fluorescence.

Claim 5

A method for obtaining a high resolution three-dimensional microscopic image of a sample having a three-dimensional thickness, comprising the steps of: emitting a parallel rays pulsed laser beam, said laser beam having a pulse duration of several ten to several hundred fs and a repetitive frequency of several ten to several hundred MH z ; shaping said laser beam into a cylindrical and annular cross-sectional ray bundle, by providing first and second convex axicon prisms which are disposed such that apexes thereof are opposed one to the other and said apexes are separated by a distance one from the other and optical axes thereof are coincident with each other and which are made of respective materials having substantially the same refractive index and shaped with a same apical angle; causing said laser beam to enter said first prism and then, after passing through said first prism, to enter said second prism; and adjusting a diameter of said ray bundle by adjusting said beam diameter either before said beam enters said first axicon prism or after said beam exits said second axicon prism; converging said shaped laser beam to produce a Bessel beam; changing a shape of three-dimensional intensity distribution of said Bessel beam by setting a ratio β of an outer diameter α of said ray bundle to an inner diameter α 1 (namely β=α/α 1 ) by adjusting said distance; labeling said sample with a predetermined fluorescent dye; irradiating said sample with said Bessel beam; detecting fluorescence light emitted by said sample responsive to irradiation by said Bessel beam; generating output signals corresponding to said detected light; and producing said microscopic image based on said output signals wherein said detecting step comprises: a) first detecting said fluorescence emitted from a surface side of said sample, and b) second detecting said fluorescence emitted from a back side of said sample; and wherein producing said microscopic image based on addition of output signals corresponding to said detected fluorescence.