Electro-optical interferometric microdensitometer system

Electro-optical apparatus comprising:

• laser and beam expander means for generating a wide, thin substantially pure Gaussian beam of light;
• means for holding a specimen to be examined in the light beam at a first location;
• and
• an array of photo-detectors at a second location spaced from the first location for receiving a pattern of interfering light waves coming from the specimen, the photo-detectors being capable of generating electrical signals in accordance with the pattern of interfering light waves, such that ultra fine elements of the specimen are characterized even though an individual photo-detector is substantially larger than an individual element of the specimen.

Apparatus for measuring the optical characteristics of a sample located along an optical axis, said apparatus comprising:

• a coherent light source for producing a beam of light along said optical axis;
• optical means for receiving said beam of light from said light source and for producing a narrow and elongated beam on said sample at a focal plane of said optical means;
• and
• means for detecting light transmitted through said sample and for producing an electrical signal proportional thereto.

A system for optically examining and characterizing ultra small details of elements of a specimen comprising:

• laser means for generating a substantially pure Gaussian narrow beam of light at a desired wavelength;
• beam expander means for expanding the Gaussian beam into a much wider beam of light and for projecting it along an optical axis;
• means for holding a specimen to be examined at a first location along the optical axis of the wider light beam;
• and
• light detector means for detecting the pattern of light waves from a specimen and for generating electrical signals therefrom, said detector means having a width commensurate with the width of the wider light beam, the detector means being located along the optical axis at a suitable distance from the first location such that ultra small details of elements of a specimen are indicated by the light waves from the specimen are characterized in the form of electrical signals generated by the detector means.

A method of optically examining a specimen by interferometric patterns of light comprising the steps of:

• generating a wide substantially pure Gaussian beam of light;
• illuminating a specimen with the beam of light to produce a "far-field" interferometric pattern of light waves at a "far-field" distance from the specimen;
• and
• detecting and converting into electrical signals the "far-field" interferometric pattern of light waves to characterize ultra fine details of the specimen over a part of its width.

A method of examining a specimen by patterns of light comprising the steps of:

• generating a substantially pure Gaussian beam of light;
• expanding the beam of light into a very much wider beam of light having substantially parallel rays;
• illuminating a specimen with the beam of light to produce a "far-field" pattern of interfering light waves;
• and
• converting into electrical signals the "far-field" pattern of light waves to characterize details of the specimen such that details having sizes on the order of the wavelength of the light beam are characterized.

Apparatus comprising:

• means for generating a Gaussian beam of light having a thickness which is substantially smaller than the width thereof;
• means for directing the beam of light so as to cause it to impinge upon an object whose physical characteristics are to be determined;
• and
• detector means for directing interferometric light waves from the object and for generating electrical signals representative of the physical structure of the object.