Vibration-resistant interferometer apparatus

A vibration-resistant interferometer apparatus comprising:

• a light source emitting a luminous flux;
• a light divider configured to divide the luminous flux into two divided luminous flues;
• an optical detouring component configured to detour one of said two divided luminous fluxes by a prescribed optical path length relative to the other one;
• an optical recombining component configured to recombine said two divided luminous fluxes into one luminous flux to form an irradiating luminous flux;
• and
• means for producing interference fringes through optical interference between a first luminous flux obtained by reflecting said irradiating luminous flux at a reference surface and a second luminous flux obtained by transmitting said irradiating luminous flux through said reference surface and then reflecting at a sample surface, and then recombining said first luminous flux and said second luminous flux such that the axis of said first luminous flux and the axis of said second luminous flux substantially coincide with one another, wherein
• said light source is a low-coherence light source for which said luminous flux, emitted from said light source, has a coherence length shorter than twice the optical distance between said reference surface and said sample surface, or a wavelength-modulated light source adjusted such that the coherence length is equivalent to the coherence length possessed by such a low-coherence light source when an image of said interference fringes is captured by an imaging element,
• a secondary reference surface that is held such that the relative positional relationship thereof with said reference surface does not change is said light divider and said optical recombining component,
• the luminous flux from the light source and reflected at said secondary reference surface is taken as a first divided luminous flux,
• the luminous flux from the light source that is transmitted through said secondary reference surface, reflected at a secondary sample surface that is held such that the relative positional relationship thereof with said sample surface does not change and faces in the same direction as said sample surface, and then transmitted through said secondary reference surface is taken as a second divided luminous flux, and
• said first divided luminous flux and said second divided luminous flux are recombined into said one luminous flux at said secondary reference surface such that an axis of said first divided luminous flux and an axis of said second divided luminous flux substantially coincide with one another to form said irradiating luminous flux.

A vibration-resistant interferometer apparatus according comprising:

• a light source emitting a luminous flux;
• a light divider configured to divide the luminous flux into two divided luminous fluxes;
• an optical detouring component configured to detour one of said two divided luminous fluxes by a prescribed optical path length relative to the other one;
• an optical recombining component configured to recombine said two divided luminous fluxes into one luminous flux to form an irradiating luminous flux;
• and
• means for producing interference fringes through optical interference between a first luminous flux obtained by reflecting said irradiating luminous flux at a reference surface and a second luminous flux obtained by transmitting said irradiating luminous flux through said reference surface and then reflecting at a sample surface, and then recombining said first luminous flux and said second luminous flux such that the axis of said first luminous flux and the axis of said second luminous flux substantially coincide with one another, wherein
• said light source is a low-coherence light source for which said luminous flux emitted from said light source, has a coherence length shorter than twice the optical distance between said reference surface and said sample surface or a wavelength-modulated light source adjusted such that the coherence length is equivalent to the coherence length possessed by such a low-coherence light source when an image of said interference fringes is captured by an imaging element,
• said irradiating luminous flux is obtained by reflecting a first divided luminous flux out of said two divided luminous fluxes from a secondary reference surface that is held such that the relative positional relationship thereof with said reference surface does not change, and reflecting a second divided luminous flux out of said two divided luminous fluxes from a secondary sample surface that is held such that the relative positional relationship thereof with said sample surface does not change and faces in the same direction as said sample surface, and then recombining said first divided luminous flux and said second divided luminous flux via said optical recombining component into said one luminous flux such that the axis of said first divided luminous flux and the axis of said second divided luminous flux substantially coincide with one another,
• said prescribed optical path length coincides with approximately twice the optical distance between said reference surface and said sample surface within the range of said coherence length of said luminous flux emitted from said light source,
• said secondary reference surface is disposed substantially in the same plane as said reference surface, and/or said secondary sample surface is disposed substantially in the same plane as said sample surface, and
• a hole is formed in a central portion of said sample surface, and said secondary sample surface is disposed inside said hole.

A vibration-resistant interferometer apparatus comprising:

• a light source emitting a luminous flux;
• a light divider configured to divide the luminous flux into two divided luminous fluxes;
• an optical detouring component configured to detour one of the divided luminous fluxes by a prescribed optical path length relative to the other one;
• an optical recombining component configured to recombine said two divided luminous fluxes into one luminous flux to form an irradiating luminous flux;
• and
• means for producing interference fringes through optical interference between a first luminous flux obtained by reflecting said irradiating luminous flux at a reference surface and a second luminous flux obtained by transmitting said irradiating luminous flux through said reference surface and then reflecting at a sample surface, and then recombining said first luminous flux and said second luminous flux such that the axis of said first luminous flux and the axis of said second luminous flux substantially coincide with one another, wherein
• said light source is a low-coherence light source for which said luminous flux, emitted from said light source, has a coherence length shorter than twice the optical distance between said reference surface and said sample surface, or a wavelength-modulated fight source adjusted such that the coherence length is equivalent to the coherence length possessed by such a low-coherence light source when an image of said interference fringes is captured by an imaging element,
• said light divider is said reference surface, and
• a luminous flux reflected at said reference surface is taken as a first divided luminous flux, a luminous flux transmitted through said reference surface, reflected at said sample surface, and then transmitted through said reference surface is taken as a second divided luminous flux, and said first divided luminous flux and said second divided luminous flux are recombined at said reference surface such that the axis of said first luminous flux and the axis of said second luminous flux substantially coincide with one another to form said irradiating luminous flux.